April 2019
CR Classification Society
FOUNDED 1951
RULES AND REGULATIONS FOR THE
CONSTRUCTION AND CLASSIFICATION OF SHIPS OF FIBREGLASS REINFORCED
PLASTICS 2019
CR
April 2019
CR Classification Society
FOUNDED 1951
CR
RULES AND REGULATIONS FOR THE
CONSTRUCTION AND CLASSIFICATION OF SHIPS OF FIBREGLASS REINFORCED
PLASTICS 2019
RULES AND REGULATIONS FOR THE
CONSTRUCTION AND CLASSIFICATION OF SHIPS OF FIBREGLASS REINFORCED
PLASTICS 2019
PART I – GENERAL REQUIREMENTS
April 2019
RULES AND REGULATIONS FOR THE
CONSTRUCTION AND CLASSIFICATION OF SHIPS OF FIBREGLASS REINFORCED PLASTICS
PART I GENERAL REQUIREMENTS 2019
PART II HULL CONSTRUCTION 2019
PART III EQUIPMENT AND FITTINGS 2019
PART IV MACHINERY INSTALLATIONS 2019
PART V ELECTRICAL INSTALLATION 2019
List of major changes in Part I from 2017 edition
1.1.2 Amend No.1
RULES AND REGULATIONS FOR
THE CONSTRUCTION AND CLASSIFICATION OF SHIPS OF FIBREGLASS REINFORCED PLASTICS
2019
PART I
GENERAL REQUIREMENTS
CONTENTS
Chapter 1 General ... 1
1.1 Application... 1
1.2 Classification and Survey of FRP Ships ... 1
1.3 Definitions ... 3
1.4 Regulations ... 3
Chapter 2 Materials ... 5
2.1 General ... 5
2.2 Definitions ... 5
2.3 Fibreglass Reinforcement ... 6
2.4 Resins ... 7
2.5 Core Materials... 7
2.6 FRP Strength Tests ... 8
2.7 Testing Procedures for Fibreglass Reinforcements ... 9
2.8 Test Procedures for Resins for Laminating ... 17
2.9 Test Procedures for Core Material for Sandwich Constructions ... 25
2.10 Test Procedures of FRP Strength Tests ... 30
Chapter 3 Works ... 35
3.1 General ... 35
3.2 Storage of Raw Materials ... 35
3.3 Moulding Shops ... 35
3.4 Quality Control ... 36
Chapter 4 Moulding ... 37
4.1 General ... 37
4.2 Environmental Conditions of Moulding Shops ... 37
4.3 Gel Coats ... 37
4.4 Manual Lamination ... 37
4.5 Spray Moulding ... 38
4.6 Sandwich Construction ... 38
4.7 Curing and Mould Releasing ... 38
Chapter 5 Connection and Fastening ... 39
5.1 General ... 39
5.2 Matting-in Connection ... 39
5.3 Mechanical Fastening ... 40
5.4 Attachment of Metal Fittings ... 40
1.1 Application
Chapter 1 General
1.1 Application
1.1.1 The Rules for the construction and classification of ships for fibreglass reinforced plastics (hereinafter referred to as the Rules) apply to the design, material, construction and equipment for ships of fibreglass reinforced plastics (hereinafter referred to as "FRP ships") intended to be assigned and registered classification with CR Classification Society (hereinafter referred to as the Society).
1.1.2 Unless otherwise specified, the requirements in the Rules are framed for FRP ships, with a designed speed not exceeding 3.70.1667 (m/s) ( = displacement in m3 corresponding to the load line defined in 1.3.6) other than oil tankers, of normal form and proportion, less than 35 meters in length, intended for unrestricted service. Special considerations will be given to large ships, ships for restricted service, ships of unusual form or proportion, novel design and arrangement, or ships intended for the carriage of special cargoes, the requirements for construction, equipment and scantlings may be properly modified.
1.1.3 The requirements in the Rules are applied to ships having structures of single skin laminates with stiffeners or sandwich constructions, moulded by hand lay-up method or spray lay-up method, using fibreglass reinforcements and unsaturated polyester resins.
1.1.4 Reinforcement materials other than fibreglass and resins other than polyester may be accepted based upon testing and approval in each individual case. Alternative constructing method, structural arrangement, equipment and scantlings are to be considered to the Society's satisfaction that they are equivalent to the requirements of the Rules.
1.2 Classification and Survey of FRP Ships
1.2.1 The classification and register of FRP ships are also to be in accordance with the applicable provisions in Part I of the "Rules for the Construction and Classification of Steel Ships" (hereinafter referred to as "the Steel Ship Rules
").
1.2.2 FRP ships with their class approved by the Society are to be recorded in the Register, and assigned a descriptive notation (FRP Hull) affixed to the classification symbols.
1.2.3 Except specified otherwise in this Chapter, The classification surveys of FRP ships are generally to comply with the requirements in Part I of the Steel Ships Rules. Plan review and surveys during or after construction are to be conducted by the Society to verify that the construction, material, equipment, machinery and electrical installation are in compliance with the Rules.
1.2.4 When FRP ships intended to be built under classification survey during construction, Plans or documents showing the following details are to be submitted and approved before the work is commenced:
(a) General arrangement
(b) List and data for raw materials (c) Midship section
(d) Construction profile and deck plan (e) Scantling calculation
(f) Laminating procedure and details of joint connections (g) Watertight and oiltight bulkhead
1.2 Classification and Survey of FRP Ships
(h) Superstructure and deckhouse (i) Fore and aft construction (j) Shaft strut
(k) Rudder and steering gear
(l) Main engine and auxiliary machinery foundations (m) Hatch and closing appliances
(n) Opening construction on weather deck
(o) Arrangement and details of hull port, door and window (p) Arrangement and details of fire safety appliances and systems (q) Machinery arrangement
(r) Propeller and shafting, or propulsion system (s) Piping systems
(t) Electrical systems
(u) Automatic and remote control systems of machinery, if CAS, CAU or CAB applied (v) Main engine, deck machinery and essential auxiliaries
(w) Other plans and documents deemed necessary by the Society
1.2.5 In addition to those required by 1.2.4, the following plans or documents are to be submitted for reference, when FRP ships are intended to be built under classification survey during construction:
(a) Specifications (b) Lines and body plan (c) Capacity plan
(d) Certificates of the FRP material tests
(e) Submission of plans and documents other than those specified above may be required where deemed necessary by the Society.
1.2.6 In the classification survey during construction, inspections are to be carried out covering all stages of work from its commencement until completion. The presence of the Surveyor is required at the following stages of work:
(a) Designated by the Society during commencement of moulding, curing and mould releasing (b) Test of FRP materials specified in Chapter 2 of Part I
(c) Connection of mouldings (e.g., deck to shell)
1.3 Definitions
(f) Test of main and auxiliary machinery (g) Sea trail
The stages for which the Surveyor's inspection required may be modified according to the actual status of facilities, technical abilities and quality control system of the works.
1.2.7 Periodical surveys are generally to be in accordance with the provisions in 1.6 of Part I of the Steel Ships Rules. In addition, the fuel oil tanks made of FRP are to be examined internally at the bottom survey.
1.2.8 In the classification of FRP ships not built under the Society's survey, the actual scantlings of main structure of the ship are to be confirmed by suitable means in addition to the inspection of hull, equipment, machinery, electrical installations, intact safety and fire protection as required for the special survey to the ship's age. Plans and documents required for the classification survey during construction are generally to be submitted for review and records.
1.3 Definitions
1.3.1 Length of ship (L) is the distance in meters on the designed load line defined in 1.3.6, from the fore side of stem to the axis of rudder stock. In case of a ship with a cruiser stern, L is as defined above or 96% of the total length on the load line, whichever is the greater.
1.3.2 Breath of ship (B) is the horizontal distance in meters between outsides of shell laminates measured on the upper surface of upper deck laminates at side at the broadest part of the hull.
1.3.3 Depth of ship (D) is the vertical distance in meters measured at the middle of L, from lower surface of bottom laminates or the intersection of the extension line of lower surface of bottom laminates with the center line of ship (hereinafter referred to as "the base point of D") to upper surface of upper deck laminates at side.
1.3.4 Midship part of ship is the parts for 0.4L amidships unless specified otherwise.
1.3.5 The end parts of ship are the parts for 0.1L from either end of the ship.
1.3.6 Load line is the waterline corresponding to the summer load draught in case of a ship which is required to be assigned with load lines, or the waterline corresponding to the designed maximum draught in case of a ship which is not required to be assigned with load lines.
1.3.7 Load draught (d) is the vertical distance in meters from the base point of D to the load line.
1.3.8 Freeboard deck is the uppermost continuous deck which has permanent means of weathertight closing of all openings in the weather part thereof, and below which all openings in the ship side are fitted with permanent means of watertightly closing. In a ship having a discontinuous freeboard deck, the lowest line of the exposed deck and the continuation of that line parallel to the upper part of the deck is taken as freeboard deck.
1.3.9 Strength deck is the uppermost deck which forms the top of effective hull girder at any part of its length and normally to which the shell laminates extend. In case of superstructures other than a sunken superstructure, which are not considered effective to longitudinal strength, the strength deck is the deck just below the superstructure deck.
1.3.10 Superstructure is an enclosed structure on the main weather deck having side plating as an extension of the side shell, or not fitted inboard of the hull side more than 4% of the breadth.
1.4 Regulations
1.4.1 While the Rules cover the requirements for the classification of FRP ships, owner, designer and builder are strongly recommended to deal with the regulations of governmental and other authorities in addition to the requirements of the Rules.
1.4 Regulations
1.4.2 Where authorized by the Administration whose flag the ship (hereinafter refer to as the administration) is entitled to fly, and upon request of owners or builders of the ship, the Society is to review plans, survey and certify the new or existing ship for compliance with the provisions of relevant International Conventions or Codes.
2.1 General
Chapter 2 Materials
2.1 General
2.1.1 The requirements in this chapter apply to raw materials for FRP structure and FRP laminates. Materials other than plastics, such as metallic materials, are to be in accordance with requirements in Part XI of the Steel Ships Rules.
2.1.2 Details of the fibreglass reinforcements, resins and sandwich core materials proposed to be used for FRP ships are to be submitted for approval before construction is commenced. The materials are to be accepted on the basis of a detailed description confirming the information given by the manufacturer with inspection and test results to the satisfaction of the surveyor.
2.1.3 At the request of manufacturers for type approval of materials, the Society is to examine the manufacturing process, inspection standards and quality control system of the works. Inspections and approval tests of materials from current production are to be carried out in the presence of the surveyor.
2.1.4 The following materials are subject to type approval:
(a) Fibreglass reinforcements, (b) Polyester products,
(c) Core materials for sandwich construction.
The type approval for each material grade is valid for a period of 5 years and will be published in the Society's list of type approved products. The approval may be withdrawn or revoked if the manufacturing process and/or material conditions at the time of approval no longer are fulfilled. The renewal of type approval certificate is to be normally assessed by checking of production control records, random inspection and sample testing.
2.2 Definitions
2.2.1 ResinResin is a reactive synthetic normally unsaturated polyester for laminating and gelcoat which is a liquid in initial stage but transformed into solid upon activation with adding substances.
(a) Polyester resin is a thermosetting resin that is formed by combining saturated and unsaturated organic acids such as orthophthalic and isophthalic acids.
(b) Vinylester resin is a thermosetting resin that consists of a polymer chain and an acr ylate or methacrylate termination.
(c) Epoxy resin is a resin that contains one or more of the epoxide groups.
(d) Accelerator is a material that, when mixed with resin, speed the cure time.
(e) Additive is a added substance usually to improve resin properties, such as plasticizers, initiators, light stabilizers and flame retardants.
(f) Catalyst is a material that is used to activate resin, causing it to harden.
(g) Cure time is the time required for resin to change from a liquid to a solid after a c atalyst has been added.
(h) Gel time is the time required to change a flowable, liquid resin into a non-flowing gel.
2.3 Fibreglass Reinforcement
(i) Exothermic heat is the heat given off as the result of the action of a catalyzed resin.
(j) Inhibitor is a material that retards activation or initiation of resin, thus extending shelf life or influencing exothermic heat or gel time.
(k) Pot life is the length of time that a catalyzed resin remains workable.
(l) Shelf life is the length of time that an uncatalyzed resin maintains its working properties while stored in a tightly sealed opaque container.
2.2.2 Reinforcement
Reinforcement is a material bonded into the plastic to improve its strength, stiffness and impact resistance.
Reinforcements are usually fibers of glass, or other material such as aramid or carbon fiber.
(a) Chopped strand mat is a fibreglass of blanket type in uniform thickness with strands of non -alkali fibreglass cut in proper length randomly oriented and held together with binder.
(b) Woven roving is a coarse fabric fibreglass woven in plain with parallel strands or rovings made of non-alkali fibreglass.
(c) Strand is a bundle of continuous filaments combined in a single, compact unit.
(d) Roving is a band or ribbon of parallel strands grouped together.
(e) Yarn is a twisted strand or strands suitable for weaving into a fabric.
(f) Binder is a polyester applied in small quantities to hold fibers together in mat form.
(g) Cloth is a fabric woven from yarn.
2.2.3 Laminate
Laminate is a material composed of successive bonded layers, or piles, of resin and fiber or other reinforced substances.
(a) Gel coat is the first resin applied to mould when fabricating a laminate to provide a smooth protective surface for laminate.
(b) Lay-up is the process of applying to a mould the layers of resin and reinforcing materials that make up a laminate. These materials are then compressed or densified with a roller or squeegee to eliminate entrapped air and to spread resin evenly.
(c) Peel ply is a partially impregnated, lightly bonded layer of fibreglass used to protect a laminate in anticipation of secondary bonding providing a cleaned fresh bonding surface.
(d) Primary bonding is the practice of bonding between two laminated surfaces when the resin on both surfaces has not yet cured.
(e) Secondary bonding is the practice of bonding fresh materials to a cured or partially cured laminate.
(f) Post cure is the act placing a laminate in higher temperature to assist in the cure cycle of the resin.
2.3 Fibreglass Reinforcement
2.4 Resins
(b) Weight per unit area and its maximum deviation, (c) Ratio in weight of residual binders or knitting agents, (d) Tensile strength of fibreglass, in case of woven rovings,
(e) Tensile strength and modulus of tensile elasticity obtained from laminated test specimens, (f) Bending strength and modulus of bending elasticity obtained from laminated test specimens.
2.3.2 Test results are to meet manufacturer's specifications and to verify the properties used in design of laminates.
Moisture content in reinforcement is to be observed.
2.3.3 Where coupling agents are used, they are to be of the saline compound or complex chromium compound which are compatible with the laminating resins.
2.3.4 For roving which will be applied by spraying, a demonstration is to be made showing that the roving is suitable for this kind of application.
2.3.5 The glass is to be of E-quality. Fibers made of other glass qualities, S or R glass, carbon or aramid fibers may be used subject to special agreement and provided that their mechanical properties and water resistance are equal or better.
2.4 Resins
The properties of a resin are to be of final form actually used in laminating with all additives and fillers included. The following properties of resins in liquid condition, cured condition and curing characteristics are to be provided.
2.4.1 Liquid properties ( at 25 °C) (a) Viscosity and thixotropic index (b) Acid value
(c) Gel time, indicate initiator (catalyst) and activator (promoter) content %, the minimum cure time and Peak exothermic temperature.
2.4.2 Cured properties of resin casting
(a) Load deflection temperature of resin casting (b) Water absorption of resin casting
(c) Barcol hardness of resin casting
(d) Tensile strength and modulus of laminated test specimens (e) Bending strength and modulus of laminated test specimens
2.5 Core Materials
2.5.1 Core materials used for sandwich construction such as honeycomb, rigid plastic foam, balsa wood are to be of sufficient tensile, compressive and shear strength which are to be verified by test for use in the design. If the core materials are manufactured into formable sheets of small blocks, the open weave backing material and adhesive are to be compatible and soluble with the laminating resin.
2.5.2 Following properties of core materials are to be examined:
2.6 FRP Strength Tests
(a) Specific gravity (b) Water absorption
(c) Tensile strength and modulus (d) Compressive strength and modulus (e) Shear strength, modulus and elongation
2.5.3 Rigid plastic foams are to be compatible with the resin system, have stable aging property, resistant to water and oils. The construction methods and procedures using foam cores are to be in accordance with manufacturer's recommendation.
2.5.4 Balsa woods are to be end grained, treated against fungal and insect attack and dried to have an average moisture content of 12%.
2.5.5 Plywood and timbers used in conjunction with plastic construction are to be seasoned, free from knots, shakes and other defects, of water resistance and suitably treated so as to have good adhesion to reinforced plastics.
2.6 FRP Strength Tests
2.6.1 The FRP strength tests are to be carried out upon completation of laminate works of FRP Ships and in case where scantling are modified according to the requirements specified in 1.2.2 of Part II before plans being submitted for approval and construction.
2.6.2 The test specimens for FRP material tests are to be cut from the laminates and sandwich laminates taken from the actual laminates or the laminates and sandwich laminates equivalent thereto. The test specimens are to be tested and inspected as follows:
(a) FRP laminates (including FRP laminates of outer skin of sandwich laminates), (i) Thickness of moulding
(ii) Barcol hardness (iii) Glass content (iv) Bending strength
(v) Modulus of bending elasticity (vi) Tensile strength
(vii) Modulus of tensile elasticity (b) Sandwich laminates
(i) Thickness of moulding of sandwich laminates
(ii) Tensile strength of sandwich laminates, only in case where the cores are born a load in the scantling calculation. In this case, the test specimens involving joints of cores are to be included.
(iii) Shearing strength of sandwich laminates, in case where the cores are reckoned in the bending strength, the test specimens involving joints of cores are to be included.
2.6.3 The FRP strength tests are to be carried out, at least on the structural members specified as follows:
(a) Bottom shell laminates (b) Side shell laminates
2.7 Testing Procedures for Fibreglass Reinforcements
2.6.4 The results of FRP strength tests specified as follows are to be submitted to the Society.
(a) Names of fibreglass reinforcements, resins for laminating and cores for sandwich construction (b) Names and amount of application of fillers
(c) Names and amount of application of sclerotics and accelerators (d) Procedures and conditions of moulding
(e) Direction of selection of test specimens (f) Dates of moulding and tests of test specimens
(g) Place of tests and environmental condition of the site of tests (h) Types of testing machines
(i) Form and dimensions of test specimens (j) Test results
2.6.5 The five test specimens are to be subjected to the FRP strength tests, unless specially specified, and the arithmetical mean of the smaller three values obtained from the five specimens is to be taken as the test result.
2.7 Testing Procedures for Fibreglass Reinforcements
2.7.1 Shape and selection of test specimens(a) The shape and selection of test specimens used for tests of fibreglass reinforcements are to be in accordance with Table I 2-1.
(b) The manufacturing methods of laminated sheet used for tests (excluding rovings for spray -up laminating) are to be in accordance with the following:
(i) The laminated plate used for tests is to have a sufficient size to arrange all the required laminated test specimens by itself after trimming away a 30 mm breadth of its edges.
(ii) The laminate constitution and glass content are to be as the following table.
Laminate constitution Glass content
Chopped mat 3-ply 30 3 (%)
Woven Roving 4-ply 50 3 (%)
(iii) The ambient temperature while laminating is to be within the temperature range stated in the specifications.
(iv) The laminating operation is to be completed within 50% of the gel time of resins for the ambient temperature.
(v) After completion of laminating operation, the laminated plate is to be left for 24 hours at a temperature of 20 5 °C, and to be subjected to curing for 16 hours in air bath at a temperature of 40 °C. The laminated plate may be cut up in proper sizes for the after cure.
(c) The manufacturing method of laminated plate used for the test of rovings for spray-up are to be in accordance with the following:
(i) The size of test specimens is to be as specified in the preceding 2.7.1(b)(i) (ii) The thickness of the test specimen is to be not less than 3mm.
(iii) The glass content is to be 30 3%.
2.7 Testing Procedures for Fibreglass Reinforcements
(iv) The after cure is to be in accordance with the preceding 2.7.1(b)(v) 2.7.2 Test Procedures
The procedure of the tests given in 2.3.1 is to be in accordance with the following:
(a) Design weight per unit area or unit length and the maximum deviation.
(i) The test samples are to be in accordance with Table I 2-1.
(ii) The weight of the test sample is to be measured to the accuracy of 0.1g.
(iii) The deviation is to be of the value obtained from the following formulae.
(1) Chopped mats and woven roving - For test sample of 1 m2
|M1− W|
W × 100 (%)
- For test sample of 300×300 m2
|M2
0.09 − W|
W × 100 (%) where:
M1 = Weight of test sample of 1 m2, in g
M2 = Weight of test sample of 300×300 mm2, in g
W = Weight of test sample per 1 m2 intended to be stated in the specification, in g (2) Rovings
|1000M
𝑙 − W|
W × 100 (%)
where:
l = Length of test sample, in m
W = Weight per 1,000 m to be stated in specification, in g M = Weight of test sample, in g
(b) Ratio in weight of binder (including sheafing agents)
(i) The test specimen are to be in accordance with Table I 2-1
(ii) Each test specimen is to be heated in a heating furnace (625 25°C) for about 10 minutes to burn out the binder or sheafing agent, then to be taken out from the furnace and left it to cool down to the room temperature.
(iii) The test sample in (ii) above is to be weighed to the accuracy of 0.1 g.
(iv) The ratio in weight of binders (including sheafing agent) is to be of the value obtained from the following formula.
W0− W1
W0 × 100 (%) where:
W0 = Weight before heating, in g W1 = Weight after cooling, in g
2.7 Testing Procedures for Fibreglass Reinforcements
(iii) When the test specimen failed or slipped at the grip of the testing machine, the measured value of this test sample is to be judged unacceptable. In such a case, an additional test specimen is to be taken for test.
(iv) The breaking load is to be taken as the tensile strength of fibreglass.
(d) Bending strength and modulus of bending elasticity obtained from laminates (i) The test specimen is to be in accordance with Table I 2-1.
(ii) The test is to be carried out after keeping the test specimen in the standard condition for 20 hours or more.
(iii) The testing arrangement of three point bending is to be in accordance with Fig. I 2-5.
(iv) The standard loading rate during test is to t/2 mm/min. (t = thickness of the test specimen in mm).
(v) The bending strength is to be of the value obtained from the following formula . 3
2∙ P𝑙
bt2 N/mm2 where:
P = Breaking load, in N l = Gauge length, in mm
b = Breadth of test specimen, in mm t = Thickness of test specimen, in mm
(vi) The modulus of bending elasticity is to be of the value obtained from the following formula.
𝑙3 4bt3∙dP
dy N/mm2 where:
(dP/dy) = Gradient of the straight portion of load-deflection curve, in N/mm y = Deflection at mid point of gauge length, in mm
l, b and t = As specified in (v) above
(e) Tensile strength and modulus of tensile elasticity obtained from laminates.
(i) The test specimens are to be in accordance with Table I 2-1.
(ii) The tests are to be carried out after keeping the test specimen in the standard condition for 20 hours or more.
(iii) The standard tensile speed is to be 5 mm/min.
(iv) When the test specimen failed outside the gauge length, the measured values of the test specimen are to be judged unacceptable. In such a case, an additional test specimen is to be taken for test.
(v) The tensile strength is to be of the value obtained from the following formula.
P
A N/mm2 where:
P = Breaking load, in N
A = Sectional area of test specimen at its mid point, in mm2
(vi) The modulus of tensile elasticity is to be of the value obtained from the following formula.
𝑙 A(dP
d𝑙) N/mm2 where:
2.7 Testing Procedures for Fibreglass Reinforcements
l = Original gauge length, in mm
A = Sectional area at mid point of test specimen, in mm2
(dP/dl) = Gradient of the straight portion of load-deflection curve, in N/mm dl = Elongation of the distance between gauge marks
2.7 Testing Procedures for Fibreglass Reinforcements
Table I 2-1
Fibreglass Reinforcements
Paragraph 2.7.2 Shape and size of test specimen Quantity Sampling procedure, etc.
(a) Deviation type1
type2
(in mm) A=1 m2 300
× 300
type 1 ... 5 pcs type 2 ... 10 pcs
Discard 30 mm from one longitudinal end and 30 mm from both transverse ends, and take a test sample of 1 m2 continuously in the longitudinal direction (See Fig. I 2-1) After measuring weight of test sample (type 1), take a square (300×
300) test specimen therefrom. (See Fig. I 2-2)
Rovings for spray-up are to have a length equivalent to approximately 15 g.
5 pcs
(b) Ratio in weight of binders
Same as type 2 in (a) 5 pcs
(c) Tensile strength of fibreglass
30 250 (in mm)
warp direction ... 5 pcs weft direction ... 5 pcs
Test specimens are to be taken in warp and weft direction,
respectively. (See Fig. I 2-3)
Finish it in the shape as shown in Fig. I 2-4
(d)
&
(e)
Bending strength obtained from laminates
250.5
t = original thickness. (in mm)
Not less than t 80
5 pcs In woven roving, 5 pieces of test specimens are to be taken in warp and weft direction, respectively.
Finish the cutout section smoothly.
(f) Tensile strength obtained from laminates
R W
G
F t t = original thickness
F = 60 0.5 (mm) G = 50 0.5 (mm) W = 25 (mm) or more R = 60 (mm) or more
standard condition ... 5 pcs
In woven roving, 5 pieces of test specimens are to be taken from warp and weft direction respectively.
Finish the cutout section smoothly.
2.7 Testing Procedures for Fibreglass Reinforcements
b b
b b
b
A A A
A
a
a a
A = approx. 1 m2
a = 30 mm b = 300 mm
Fig. I 2-1
Selection of Test Specimens from Fibreglass Reinforcements
Fig. I 2-2
Selection of Test Specimens from
Fibreglass Reinforcements
2.7 Testing Procedures for Fibreglass Reinforcements
a
b
A B b
a
A: the test specimen in the direction of warp B: the test specimen in the direction of weft a = approx. 30 mm
b = approx. 250 mm
Fig. I 2-3
Selection of Tensile Test Specimen from Woven Roving Reinforcements
Grip
approx. 250 mm approx. 150 mm
25 mm approx. 30 mm
Grip
Fig. I 2-4
Tensile Test Sample of Woven Roving
t
l = 1 5 t ~ 1 7 t R 3 . 2 m m
o r m o r e R 3 . 2 m m o r
m o r e R 5 m m o r m o r e P
Fig. I 2-5
Testing Arrangement of Three Point Bending
This part of fibre is to be removed, and the breadth of finished specimen is to be 25 mm
2.7 Testing Procedures for Fibreglass Reinforcements
Table I 2-2
Acceptance Criteria for Fibreglass Reinforcements
Test item Acceptance criteria
Deviation Chopped mat 1m2 ... Not greater than 10% for each specimen 300 mm × 300 mm .... Not greater than 20% for each specimen Woven Roving 1m2 ... Not greater than 3% for each specimen
300 mm × 300 mm .... Not greater than 5% for each specimen Rovings 15g ... Not greater than 10% for each specimen Ratio in weight of
residual binders
Chopped mat Mean value ... Not greater than 10%
Test results of at least 4 test specimens are not to be greater than 10%
Woven Roving Mean value ... Not greater than 1%
Test results of at least 4 test specimens are not to be greater than 1%
Rovings Mean value ... Not greater than 3%
Test results of at least 4 test specimens are not to be greater than 3%
Tensile strength of fibreglass of glass woven roving
Mean value ... Not less than 0.35W (kg) W: the stated weight (g)
Test results of at least 4 test specimens in 5 test specimens of respective warp and weft directions are not to be less than 0.35W (kg)
Chopped mat Roving
Bending strength Mean value ... Not less than 160 N/mm2
Test results of at least 4 test specimens are not to be less than 157 N/mm2 Modulus of
bending elasticity
Mean value ... Not less than 7000 N/mm2
Test results of at least 4 test specimens are not to be less than 7000 N/mm2 Woven Roving Bending strength Mean value ... Not less than 280 N/mm2
Test results of at least 4 test specimens are not to be less than 280 N/mm2 Modulus of
bending elasticity
Mean value ... Not less than 12900 N/mm2
Test results of at least 4 test specimens are not to be less than 12900 N/mm2 Chopped mat
Roving
Tensile strength Mean value ... Not less than 85 N/mm2
Test results of at least 4 test specimens are not to be less than 85 N/mm2 Modulus of tensile
elasticity
Mean value ... Not less than 7500 N/mm2
Test results of at least 4 test specimens are not to be less than 7500 N/mm2 Woven Roving Tensile strength Mean value ... Not less than 190 N/mm2
Test results of at least 4 test specimens are not to be less than 190 N/mm2 Modulus of tensile
elasticity
Mean value ... Not less than 1600 N/mm2
Test results of at least 4 test specimens are not to be less than 1600 N/mm2
2.8 Test Procedures for Resins for Laminating
2.8 Test Procedures for Resins for Laminating
2.8.1 Shapes and Selection of Test Specimens(a) The shape and selection of test specimens used for the tests of resins for laminating are to be in accordance with Table I 2-3.
(b) The manufacturing methods of resin casting test specimens are to be in accordance with the following:
(i) The sclerotics and accelerators are to be as specified by the manufacturer of the resins.
(ii) The size of cast sheet is to be such that all test specimens required in Table I 2 -3 for the resin casting test specimen can be cut out of the sheet.
(iii) The cure time, temperature and after cure are to be as specified by the manufacturer of resins.
(c) The manufacturing procedures of laminates used for tests are to be in accordance with the following : (i) The laminating arrangements is to be of chopped mat with weight per unit area of 450 g/m2 in 3-ply
and the glass content is to be 30 3% in weight.
(ii) For other procedures, apply to the requirements in 2.7.1(b) correspondingly.
2.8.2 Test Procedures
The procedures for the tests given in 2.4 are to be in accordance with the following:
(a) Viscosity and thixotropy
(i) The test resins are to be as given in Table I 2-3.
(ii) Brookfield viscometer is to be used.
(iii) The rotor and guard (or sleeve guard) chosen according to the predicted viscosity of the liquid sample are to be mounted on the viscometer.
(iv) The test liquid resins (25 0.5 °C) after being stirred well are to be filled into the beaker to a depth so that the reference mark on the rotor may be equal to the liquid level.
(v) After leaving still for approximately 5 minutes and then turning the rotor at a rotational speed of 60 rpm for 3 minutes, the reading of the scale is to be taken. The viscosity is to be obtained by multiplying the reading by a coefficient determined according to the type of rotor used an d rotational speed.
(vi) After keeping still for another 5 minutes and then turning the rotor at a rotational speed of 6 rpm for 3 minutes, the reading is to be taken for obtaining the viscosity.
(vii) The thixotropy index is to be obtained by dividing the viscosity determined at the rotor run of 6 rpm by the viscosity at 60 rpm.
(viii) The operations shown in (v) and (vi) above are to be repeated for two times or more and the respective mean values are to be regarded as the "viscosity" and "thixotropy inde x".
(b) Gel time, minimum cure time and peak exothermic temperature.
(i) The test resins are to be given in Table I 2-3.
(ii) The testing apparatus for hardening characteristics at room temperature is to be fixed in a thermostatic water bath (25 0.5 °C). (See Fig. I 2-6)
(iii) The test resins are to be dipped in the thermostatic water bath and then the specified amount of sclerotics is to be added thereto when the temperature of the test resins reached 25 0.5 °C, and the mixture is to be stirred evenly.
(iv) The test resins added with sclerotics are to be filled into a test tube of 18 mm in diameter to a depth of 100 mm.
(v) The 18 mm dia. test tube is to be fixed in a test tube of 30 mm in diameter so that the top surface of the test resins assumes approximately 10 mm below the liquid surface of the thermostatic water bath.
2.8 Test Procedures for Resins for Laminating
(vi) The welded junction of thermocouple is to be placed at half the depth of the test resins and to be fixed at the centre of the test tube. However, a thermocouple ensleeved in a pro tection tube or a thermister may be used in place of the above thermocouple.
(vii) The time in minutes required for the test resins to reach a temperature of 30 °C from the time when the sclerotic are mixed is to be taken as the gel time, and the time in minutes required to reach the highest temperature after adding the sclerotics is to be taken as the minimum cure time, and the temperature indicated as the maximum temperature of the test resin is to be taken as the peak exothermic temperature (°C).
30
18
9 50
50
100
Air mantle Test tube
Test tube for thermal insulation
Welded junction of thermocouple
Test resin Bath liquid Stoppers
Adhesive tape
Approx. 10
165
Fig. I 2-6
Testing Apparatus for Hardening Characteristics at Room Temperature
2.8 Test Procedures for Resins for Laminating
(viii) Measurements are to be taken for two or more times, and the respective mean values are to be regarded as the "gel time", "minimum cure time" and "peak exothermic temperature".
(ix) The types and amounts of the sclerotics and accelerators are to be recorded.
(c) Acid value
(i) Take 1 g of the test resins, add it to about 10 ml of mixed solvent［mixture of 7 parts by mass of toluene (reagent) and 3 parts by mass of methyl alcohol (reagent)］, and stir the mixture well.
(ii) Add the mixed indicator and titrate the solution with 0.1 mole/l ethyl alcoholic potassium hydroxide solution.
(iii) When the colour of the solution turns from green into pale violet, take it as a point of termination.
(iv) The acid value is to be of the value obtained from the following formula.
5.61υf S where:
υ = Consumption of 0.1 mole/l ethyl alcoholic potassium hydroxide, in ml f = Factor of 0.1 mole/l ethyl alcoholic potassium hydroxide
S = Mass of test resins, in g
The mixed indicator is the reagent obtained by adding 20 ml of distilled water to 0.1 g of finely ground bromthymol blue and 0.1 g of phenol red, and adding further 0.1 mole/l ethyl alcoholic potassium hydroxide solution thereto to the discolouring range while stirring it well, and by diluting it further with distilled water to a volume of 200 ml.
(d) Water absorption rate of cast test specimens
(i) The test specimens are to be in accordance with Table I 2-3.
(ii) Put a filter paper on an asbestos board (thickness: approximately 10 mm), place the test specimen thereon, and heat the test specimen in a thermostatic air oven (50 2 °C) for 24 1 hours.
(iii) Cool the test specimen subjected to heating process in (2) above in a desiccator and measure the weight.
(iv) Immerse the test specimen in a container with a lid filled with sufficient volume of distilled water, leave the container in a thermostatic water bath (25 1 °C) for 24 hours, and then take the test specimen out, wipe the surface water and measure the weight. During immersion in distilled water, the test specimens are to be hold not to be brought in contact with each other.
(v) The water absorption rate is to be of the value obtained form the following for mula.
W1− W0
W0 × 100 (%) where:
W0 = Weight of test specimen after heating, in g
W1 = Weight of test specimen after immersion in water, in g (e) Barcol hardness of cast test specimens
(i) Use the Barcol hardness tester.
(ii) Hold the hardness tester in such a manner that the point contacts at right angles with the testing surface of the test specimen which is placed on a hard base.
(iii) Apply 4.5 kg to 6.8 kg of an impact pressure and read out the maximum indication on the hardness tester.
(iv) Ensure that the measuring point is 3 mm or more apart from the periphery of test specimen and other measuring points, and that those measuring points clear the areas from which other test specimens are taken.
2.8 Test Procedures for Resins for Laminating
(v) Take measurements at least 10 points.
(f) Tensile elongation and tensile strength of the cast test specimens.
(i) The test specimens are to be in accordance with Table I 2-3.
(ii) The standard tensile speed is to be 5 mm/min.
(iii) When the test specimen failed outside the place between gauge points, the measured value of such a test specimen is to be judged unacceptable, and a new test specimen is to be taken for additional test.
(iv) The tensile elongation is to be obtained from the following formula.
Elongation of the gauge length at failure
Initial gauge length × 100 (%)
(v) The tensile strength is to be obtained from the following formula.
P
A N/mm2 where:
P = Breaking load, in N
A = Sectional area of test specimen at mid point, in mm2 (g) Load deflection temperature of cast test specimens
(i) The test specimens are to be in accordance with Table I 2-3.
(ii) The testing apparatus is to be as shown in Fig. I 2-7.
(iii) The weight of balance weight is to be of the value obtained from the following formula.
0.123 ∙th2
𝑙 − Q kg where:
t = Thickness of test specimen, in mm h = Height of test specimen, in mm l = Distance between supports, in mm
Q = Weight, in kg, obtained by adding the load reading on a dial gauge to the weight of loading rod including the weight pan.
(iv) Fix the testing apparatus with the test specimen in an oil bath, apply load and leave it from the initial temperature of 25 1 °C for 5 minutes.
(v) Raise the temperature of the oil bath at a rate of 2.0 0.2 °C /min.
(vi) The temperature when the deflection reaches 0.26 mm is to be taken as the load deflection temperature.
(h) Barcol hardness of the laminate test specimens
The requirements in (e) above are to apply correspondingly.
(i) Bending strength and modulus of bending elasticity obtained by laminate test specimens (i) The test specimens are to be in accordance with Table I 2-3.
(ii) The testing procedures are to be in accordance with 2.7.2(d).
2.8 Test Procedures for Resins for Laminating
(k) High temperature characteristics obtained by laminate test specimens.
(i) Barcol hardness
Leave the test specimen at 60 1 °C for 24 hours and carry out the test specified in (e) above within one minute.
(ii) Bending strength and modulus of bending elasticity
Leave the test specimen at a temperature of 60 1 °C for 24 hours and then carry out the test specified in (i) above at a temperature of 60 2 °C.
2.8 Test Procedures for Resins for Laminating
h
T e s t s p e c i m e n s u p p o r t i n g b a s e l 1
l2 l 2
R R
R
t T e s t c
s p e c i m e n I n d e n t e r
L o a d r o d
l 1 = 100 2.0 (mm) l 2 = 50 1.0 (mm) R = 3.0 0.2 (mm)
t = thickness of test specimen (mm) h = height of test specimen (mm) c = to be 13 mm or more
Unit: mm
Metal frame Metal support 100 2
Metal support
Stirrer 13 or
more
Test specimen 2 or less
Test specimen Thermometer gauge
Dial
Balance weight
Fig. I 2-7
Load Deflection Temperature Measuring Arrangement
2.8 Test Procedures for Resins for Laminating
Table I 2-3
Resins for Laminating (Unit: mm)
Paragraph 2.8.2 Shape and size of test specimen Quantity Selection of test specimen, etc.
(a) Viscosity and thixotropy index
Resins As required When resins are sampled, the
contents of vessel are to be stirred well to make them homogeneous, and take test resins into a suitable dry and clean vessel of two times the necessary volume for test and a light-proof plug is to be provided
(b) Gel time, minimum cure time and peak exothermic temperature
Resins 501g
(Note)
(c) Acid value Resins 1 g
(d) Water
absorption rate 501
501 30.2
5 cast test specimens
(e) (h)
Barcol hardness Cast test specimens Laminate test specimens (g) Load deflection
temperature 12.70.2
Not less than 110 6.40.2
3 cast test specimens
(f) (j)
Tensile strength R W
G
F t Cast test specimens
t = 3 0.2 (mm) F = 60 0.5 (mm) G = 50 0.5 (mm) W = 12.5 (mm) or more R = 60 (mm) or more Laminate test specimens t = original thickness F = 60 0.5 (mm) G = 50 0.5 (mm) W = 25 (mm) or more R = 60 (mm) or more
5 cast test specimens
5 laminate test specimens
(i) Bending strength of laminated test specimens
250.5
Not less than 180
5
(k) High temperature characteristics of laminated test specimens
The same as in (h) and (i)
Note: In the case of no-accelerated resins, the specified amount of accelerators is to be added and stirred according to the weight of the resins.
2.8.3 Criteria
The acceptable criteria of the test results are to be not less than the value given in Table I 2-4.
2.8 Test Procedures for Resins for Laminating
Table I 2-4
Acceptable Criteria for Resins for Laminating
Test item Acceptable criteria
(a) Viscosity Thixotropy index
1.5 ~ 8 (Poise) 1.2 ~ 4
(b) Gel time
Minimum cure time
Peak exothermic temperature
For reference For reference
Not more than 190 °C
(c) Acid value For reference
(d) Water absorption rate
Cast test specimen Mean value to be not more than 0.25%
(e) (h)
Barcol hardness Cast test specimen Laminate test specimens
Mean value to be not less than 35 Mean value to be not less than 40 (f)
Cast test
Tensile elongation Mean value to be not less than 1.3%
Test results of at least 4 test specimens are to be not less than 1.3%
specimens Tensile strength For reference
(g) Load deflection temperature Mean value to be not less than 60 °C
Test results of at least 2 test specimens are to be not less than 60 °C (i) Bending strength
Modulus of bending elasticity
Mean value to be not less than 160 N/mm2 Mean value to be not less than 7000 N/mm2 (j)
Laminated test specimens
Tensile strength
Modulus of tensile elasticity
Mean value to be not less than 85 N/mm2 Mean value to be not less than 7500 N/mm2
(k)(1) Barcol hardness Mean value to be not less than 60% of the mean value of test (h) (k)(2) Bending strength
Modulus of bending elasticity
Mean value to be not less than 70% of the mean value of test (i) Mean value to be not less than 50% of the mean value of test (i)
2.9 Test Procedures for Core Material for Sandwich Constructions
2.9 Test Procedures for Core Material for Sandwich Constructions
2.9.1 Shapes and Selection of Test Specimens(a) The shape and selection of test specimens used for the test of core materials for sandwich construction are to be in accordance with Table I 2-5.
(b) The manufacturing methods of sandwich constructions for the test are to be in accordance with the following:
(i) The core material is to be the largest thickness to be used as primary structural members of hull construction.
(ii) On both sides of the core, the M-R-M-R-M laminates are to be applied, where M denotes chop mats (weight per unit area 600 g/m2) and R, woven roving (weight per unit area 810 g/m2).
(iii) The glass content is to be approximately 30% at the portion of chops mats, and approximately 50%
at the portion of woven roving.
(iv) The direction of warp of the woven roving is to be aligned with the longitudinal direction of the test specimen.
(v) In the case of the fibre reinforced plastics foam, test specimens of which longitudinal direction is aligned respectively with the direction of the maximum strength and the direction of the minimum strength of the core material are to be manufactured.
2.9.2 Test Procedures
(a) The test procedures for the hard plastics foam specified in 2.5.2 are to be in accordance with the following:
(i) Specific gravity
(1) The test specimens are to be in accordance with Table I 2-5.
(2) Leave the test specimen in a thermostatic air oven (25 0.5 °C) for about 30 minutes and measure the dimension and weight.
(3) The size of the test specimen is to be measured to an order of 0.1 mm for the thickness, length and breadth.
(4) The weight of the test specimen is to be measured to the order of 0.1 g.
(5) The specific gravity is to be for the value obtained from the following formula.
W/V where:
W = Weight of test specimen, in g
V = Weight of pure water corresponding to the volume of test specimen, in g (ii) Water absorption rate
(1) The test specimens are to be in accordance with Table I 2-5.
(2) The surface skin of the test specimen, if such is the case, is to be removed, and the dimensions are to be measured to the order of 0.1 mm.
(3) The test specimen is to be submerged in fresh water (23 3 °C, 60 mm in depth below the water surface) for 10 seconds.
(4) The test specimens is to be placed on a wire gauze of 3 mm mesh titled at 30 degree to the vertical for 30 seconds, and then the reference weight (Wo) is to be measured to the order of 0.01g.
(5) The test specimens of which reference weight has been measured is to be soaked in fresh water (23 3 °C) for 24 hours with a pressure of 10 N/mm2.
(6) The weight of the test specimen (W1) is to be measured by the same procedure as specified in (4) above.
(7) The water absorption rate is to be obtained from the following formula.
2.9 Test Procedures for Core Material for Sandwich Constructions
W1− W0
A × 100 g/100cm2 where:
W1 = Weight after the final water absorption, in g W0 = Reference weight, in g
A = Surface area of test specimen, in cm2
(iii) Compressive strength and modulus of compressive elasticity.
(1) The test specimens are to be in accordance with Table I 2-5.
(2) The size of the test specimen is to be measured to the order of 0.1 mm.
(3) Compression to be applied in the direction thickness of the product.
(4) The standard compression speed is to be 5 mm/min.
(5) The compressive strength is to be obtained from the following formula.
Pc
A N/mm2 where:
Pc = Load at which 0.2% strain is occurred from the elastic limit, in N A = Pressure bearing area of test specimen, in mm2
(6) The modulus of compressive elasticity is to be obtained t
A∙ (dP
dt) N/mm2 where:
(dP/dt) = Gradient of the straight portion of load-contraction curve, in N/mm (See Fig. I 2-8)
t = Thickness of test specimen
A = Pressure bearing area of test specimen, in mm2 (iv) Softening rate
The modulus of compressive elasticity at a temperature of 60 °C is to be measured by suitable means.
The method specified in 2.8.2(g) may be applied correspondingly.
(v) Tensile strength and modulus of tensile elasticity
(1) The test specimens are to be in accordance with Table I 2-5.
(2) The test procedure is to be in accordance with 2.7.2(f).
(vi) Bending strength and modulus of bending elasticity.
(1) The test specimens are to be in accordance with Table I 2-5.
(2) The testing arrangement of four point bending is to be in accordance with Fig. I 2-9.
(3) The standard loading speed is to be t/2 mm/min.
t = thickness of test specimen, in mm
(4) The bending strength is to be obtained from the following formula.
3PL1
bt2 N/mm2 where:
L1 = Outer span, in mm
b = Breadth of test specimen, in mm
2.9 Test Procedures for Core Material for Sandwich Constructions
Maximum load Pc Load corresponding to elastic limit
Contraction 0.2% contraction
Fig. I 2-8
Load-Contraction Diagram
(5) The modulus of bending elasticity is to be obtained from the following formula.
3 4∙L1L22
bt3 ∙dP
dδ N/mm2 where:
L1 = Outer span, in mm L2 = Mid span, in mm
(dP/d) = Gradient of straight portion of load-deflection at mid point of gauge length
= Deflection at mid point of gauge length, in mm
2.9 Test Procedures for Core Material for Sandwich Constructions
L2 = 100 mm L1 L1
R R
R R
R = 3.2 mm or more
Fig. I 2-9
Testing Arrangement of Four Point Bending
(vii) Shearing strength of sandwich constructions(1) The test specimens are to be in accordance with Table I 2-5.
(2) The testing arrangement of four point bending is to be in accordance with Fig. 2 -9 (3) The standard loading speed is to be t/2 mm/min.
t = thickness of test specimen, in mm
(4) The shearing strength is to be obtained from the following formula.
Pb
2(tf+ tc)b N/mm2 where:
Pb = Breaking load of core material, in N
tf = Mean thickness of inner layer and outer layer of FRP laminates, in mm tc = Thickness of core material, in mm
b = Breadth of test specimen, in mm
(5) The outer span (L1) is to be referred to the value obtained from the following formula.
However, in case where either the outer or inner FRP laminates fails, retest is to be carried out with the smaller outer span.
L1< Z ∙ σf
(tf+ tc)bτc mm where:
Z = Section modulus of test specimen, in mm3 tf = Mean thickness of FRP laminates, in mm tc = Thickness of core material, in mm B = Breadth of test specimen, in mm
σf = Tensile strength of FRP laminates, in N/mm2
τc = Imaginary shearing strength of core material, in N/mm2
(b) The test procedures for balsa are to be in accordance with the following:
2.9 Test Procedures for Core Material for Sandwich Constructions
(ii) Moisture content
(1) After having dried the test specimen in (i) above in the thermostatic air oven to a fixed weight, the weight is to be measured to the order of 0.1g.
(2) The moisture content is to be of the value obtained from the following formula.
W1− W2
W2 × 100 (%) where:
W1 = Weight at the standard condition, in g W2 = Weight after drying, in g
(iii) Compressive strength in fibrous direction and modulus of compressive elasticity.
The test procedure is to be in accordance with 2.9.2(a)(iii). However, Pc shown in (5) is the maximum load (N). In this case, the specific gravity of the test specimen is to have been measured in accordance with (i) above.
(iv) Shearing strength of sandwich constructions.
The test procedure is to be in accordance with 2.9.2(a)(vii).
2.10 Test Procedures of FRP Strength Tests
Table I 2-5
Core Materials for Sandwich Construction (Unit: mm)
Paragraph 2.9.2(a)/(b) Shape and size of test specimen Quantity Selection of test specimen, etc.
(1) Specific gravity Hard plastic foam
100
t: original thickness 100 t
5
Balsa
Product balsa of original thickness
Compression test specimen (3) is to be used
10 5
Product balsa boards (artificially dried balsa boards bonded in the same direction (block) to be cut at right angle to fibrous direction) are to be taken from different lots as far as practicable.
(2) Water absorption The same as in hard plastic foam 5 (2) Moisture content
100
t: original thickness 100 t
10 One each test specimen is to be taken from each product balsa of which the specific gravity was measured.
(3) Compression test
Hard plastic foam a = 50 (mm)
Balsa a = 20 ~ 50 (mm) t = 50 (mm)
Fibre Direction
a
a t
5 Materials for test are to be selected as differently on specific gravity as possible among those forming a block of balsa products, and test specimens are to be taken from those respective materials.
(5) Tensile test R W
G
F t t = original thickness or 20 (mm) F = 600.5 (mm)
G = 500.5 (mm) W = 25 (mm) or more R = 60 (mm) or more
5
(6) Bend test
50
350 or more t
t = original thickness or 20 (mm)
5
(7) Shearing test
500.5
600 or more t
t : to be in accordance with 2.9.1(b)(i)
5
2.10 Test Procedures of FRP Strength Tests
2.10.1 Manufacture of test laminates for FRP laminates and sandwich constructions
2.10 Test Procedures of FRP Strength Tests
T B
B T
T B
60 mm or more 60 mm or more
60 mm or more
Warp direction of roving clothes T denotes tensile test specimen (5 pcs.) B denotes bending test specimen (5 pcs.)
signifies the measuring area of Barcol hardness test or glass content measurement
Fig. I 2-10
Location of Selection of Test Specimens
(a) One each of FRP test laminates or test laminates of sandwich construction which are of the same laminate composition and the same moulding procedures as those for bottom laminates, side shell laminates and upper deck laminates is to be manufactured. However, when either of the bottom laminates, side shell laminates or upper deck laminates has the same laminate composition with the other, one test laminate may be manufactured for those of the same laminate composition.
(b) The size of the test laminates is to be sufficient to cut all the test specimens specified in the following 2.10.2 (See Fig. I-2-10) and 2.10.3.
2.10.2 The selection of test specimens is to be in accordance with the following (a) and (b).
(a) FRP laminates (including the FRP laminates of the inner layer and outer layer of sandwich construction).
(i) The tensile test specimens and bending test specimens are to be cut alternately from the test laminates clearing 60 mm belt from the periphery. (See Fig. I 2-10)
(ii) The test laminates for Barcol hardness and glass content measurement are to be of thos e hatched sections in figure.
(iii) The test laminates of the inner layer and outer layer of FRP laminates of sandwich construction are to be taken by cutting cores out of the moulded sandwich constructions and smoothing their surfaces.
(b) Sandwich constructions
(i) For the selection of the bend test specimens, tensile test specimens and shearing test specimens, the requirements in (a)(i) above apply correspondingly. When the cores are reckoned in strength, a joint is to be provided.
2.10.3 The shape and size of the test specimens are to be in accordance with Table I 2-6.
2.10 Test Procedures of FRP Strength Tests
Table I 2-6
Shape and Size of Test Specimens
Item Test specimen Quantity
FRP laminates Sandwich construction
Thickness of moulding Bend test specimen and tensile test specimen are to be used
Bend test specimen, shearing test specimen and tensile test specimen are to be used Glass content 2g or more for each one
The periphery is to be finished smoothly
3
Bend test specimen and shearing test specimen
Bend test specimen
b
20t or more t
Shearing test specimen
b
l t
Cores
L1 L2 L1
C
Cores Joint
t = original thickness L1 = 100 ~ 200 (mm) L2 = 100 (mm) l = 2L1+L2+60 (mm) C = approx. 10 (mm)
(When the cores are reckoned in strength, a joint is to be provided at the position shown on the drawing.)
5
t (mm) b (mm) t (mm) b (mm)
Not more than 20
Over 20 but not more than 35 Over 35 but not more than 50
30 0.5 50 0.5 80 0.5
Not more than 20
Over 20 but not more than 35 Over 35 but not more than 50
30 0.5 50 0.5 80 0.5 Tensile test specimen R
W
G
F t
t = original thickness F = 600.5 (mm) G = 500.5 (mm) W = 25 (mm) or more R = 60 (mm) or more
R W
G
F t
Joint t = original thickness F = 600.5 (mm) G = 500.5 (mm) W = 25 (mm) or more R = 60 (mm) or more
When the cores are reckoned in strength, a joint is to be provided at the centre of the parallel part.
5
