ISO/TC 61/SC 13/WG 2 - Laminates and moulding compounds

This document specifies methods for determining the compressive properties, in directions parallel to the plane of lamination, of fibre-reinforced plastic composites, based on thermosetting or thermoplastic matrices. The compressive properties are of interest for specifications and quality-control purposes. The test specimens are machined from a flat test plate, or from suitable finished or semi-finished products. Two loading methods and two types of specimen are described. The loading methods are: — Method 1: provides shear loading of the specimen (gauge length unsupported) — Method 2: provides combined loading of the specimen (gauge length unsupported) NOTE For tabbed specimens loaded using method 2, load is transferred through a combination of end-loading and shear-loading through the tabs. The specimen designs are: — Type A specimen: rectangular cross-section, fixed thickness, end-tabbed (mainly for aerospace style preimpregnates (~ 0,125 mm ply thickness) — Type B specimen: rectangular cross-section, range of thicknesses, untabbed or end-tabbed, two specimen sizes are available (B1 and B2). The Type A specimen is used for unidirectionally or biaxially reinforced materials tested in the fibre direction, where the fibres are normally either aligned continuous or aligned long (>7,5 mm) discontinuous. The Type B1 and B2 specimens are used for multi-directional aligned; mat, fabric and other multi-directionally reinforced materials where the fibre structure is more complex and/or coarser. This document gives criteria for checking that the combination of test method and specimen design result in valid failures. It is noted that alternative test method/specimen combinations will not necessarily give the same result. The methods specify required dimensions for the specimen. Tests carried out on specimens of other dimensions, or on specimens that are prepared under different conditions, can produce results that are not comparable. Other factors, such as the speed of testing, the support fixture used and the conditioning of the specimens, can influence the results.

This document specifies a method for determining the compressive properties in the pultruded fibre reinforced plastic (FRP) using full-section compressive tests. It is applicable to pultruded FRP profiles. The scope is not limited to types of fibres and resins.

This document specifies methods for determining the through-thickness properties (i.e. strength, modulus of elasticity, Poisson’s ratio and strain-to-failure) of fibre-reinforced plastic composites using either rectangular prism and/or waisted block specimens. The methods are suitable for use with a variety of aligned and non-aligned, continuous, and discontinuous fibre formats, with both thermoset and thermoplastic matrices, ranging from 20 mm to 40 mm in thickness. Three specimen types are described in this document. These are: — Type I - fixed rectangular cross-section along length of specimen. It is the preferred specimen for determining elastic properties. — Type II - waisted rectangular cross-section, variable cross-section along length of specimen. It is only suitable for determining tensile strength values and is the preferred specimen for highly anisotropic and thermoplastic materials. — Type III - waisted rectangular cross-section, fixed cross-section along the gauge-length of specimen. It is used to provide both elastic and strength property data and is the preferred specimen for generating a full stress-strain response. Specimen types I and II are also suitable for use with unreinforced plastics but are unsuitable for use with rigid cellular materials and sandwich structures containing cellular materials. Two testing modes are covered: — Method A – Tension — Method B – Compression

This document specifies the test conditions for the determination of the tensile properties of isotropic and orthotropic fibre-reinforced plastic composites, based upon the general principles given in ISO 527-1. NOTE 1 Unidirectional reinforced materials are covered by ISO 527-5. The methods are used to investigate the tensile behaviour of the test specimens and for determining the tensile strength, tensile modulus, Poisson's ratios and other aspects of the tensile stress-strain relationship under the defined conditions. The test method is suitable for use with the following materials: — fibre-reinforced thermosetting and thermoplastic composites incorporating non-unidirectional reinforcements such as mats, woven fabrics, woven rovings, chopped strands, combinations of such reinforcements, hybrids, rovings, short or milled fibres or preimpregnated materials (prepregs); NOTE 2 Injection moulded specimens are covered by ISO 527-2. — combinations of the above with unidirectional reinforcements and multidirectional reinforced materials constructed from unidirectional layers, provided such laminates are symmetrical; NOTE 3 Materials with completely or mainly unidirectional reinforcements are covered by ISO 527-5. — finished products made from materials mentioned above. The reinforcement fibres covered include glass fibres, carbon fibres, aramid fibres and other similar fibres.

This document specifies the test conditions for the determination of the tensile properties of unidirectional fibre-reinforced plastic composites, based upon the general principles given in ISO 527-1. NOTE Isotropic and orthotropic reinforced materials are covered by ISO 527-4. The methods are used to investigate the tensile behaviour of the test specimens and for determining the tensile strength, tensile modulus, Poisson's ratios and other aspects of the tensile stress-strain relationship under the conditions defined. The test method is suitable for all polymer matrix systems reinforced with unidirectional fibres and which meet the requirements, including failure mode, set out in this document. The method is suitable for composites with either thermoplastic or thermosetting matrices, including preimpregnated materials (prepregs). The reinforcements covered include carbon fibres, glass fibres, aramid fibres and other similar fibres. The reinforcement geometries covered include unidirectional (i.e. completely aligned) fibres and rovings and unidirectional fabrics and tapes. The method is not normally suitable for multidirectional materials composed of several unidirectional layers at different angles (see ISO 527-4).

This document specifies a thermogravimetric method for the determination of fibre weight content by weight percent, of carbon fibre reinforced composites. This method applies to pre-products, such as, prepregs, parts and products of carbon fibre reinforced composites.

This document specifies accelerated moisture absorption properties and supersaturated conditioning by moisture for fibre-reinforced plastics) using sealed pressure vessel at higher temperature than 100 °C with saturated water vapour at used heating temperature. The purpose of this moisture absorbing procedure is to screen test specimens with moisture by mechanical or thermal properties. This document applies to carbon-fibre materials and their products with either thermoset or thermoplastic matrices, with a Tg greater than 150 °C. This document can also apply to materials reinforced with other fibres (e.g. glass-fibres) with a Tg greater than 150 °C.

This document specifies a method for the determination of the mass per unit area. It also specifies five methods (Method A to Method E) for the determination of the fibre mass per unit area of moulding compounds and prepregs. The five methods are as follows: — Method A: Extraction by Soxhlet; — Method B: Extraction by immersion in solvent in a beaker; — Method C: Decomposition by loss ignition; — Method D: Extraction by wet combustion; — Method E: Method by calculation. This document is applicable to the following types of materials: — moulding compound and preimpregnated unidirectional sheet, tape, fabric and mats; — prepregs in which any type of reinforcement (aramid, carbon, glass, etc.) and any type of matrix (thermosetting or thermoplastic) has been used. Typically, reinforcement fibres are coated with sizing or finishes. These normally dissolve with the resin and are, therefore, included in the resin content. This document is not applicable to the following types of prepregs: — those containing reinforcements which are soluble (or partly soluble) in the solvents used to dissolve the resin.

1.1 This document specifies a procedure for the initial qualification of composite materials in order to allow quality control, material selection and preliminary design to be undertaken. It provides a single procedure allowing quicker and lower cost qualification compared to multiple bi-lateral qualification against different bespoke user needs. This document focuses on developing B-basis design allowables. 1.2 The procedure comprises a standard qualification plan (SQP) that includes the minimum common test requirements for more highly anisotropic composite materials. Further test requirements are encompassed in an extended qualification plan (EQP), which includes options representing specific in-service features. A reduced qualification plan (RQP) scheme, using the same core structure of test plate preparation and test methods as the SQP, is available for less highly anisotropic and tending towards nominally isotropic composite materials. 1.3 The procedure is suitable for fibre-reinforced thermoset, and thermoplastic, based material systems intended for structural or semi-structural applications. Individual test method standards referred to in this document provide more details as to the classes and types of composite materials that are covered in each case. 1.4 Annexes A and B are included to support presentation of the data obtained in a consistent database and to provide statistical procedures for the determination of B-basis design allowables, respectively.

This document specifies a method using a shear test apparatus for measuring the in-plane shear stress/shear strain response, shear modulus and shear strength of continuous-fibre-reinforced plastic composite materials with fibre orientations of 0° and 0°/90°. This method is applicable to thermoset and thermoplastic matrix laminates made from unidirectional layers/non-woven fabrics and/or fabrics including unidirectional fabrics, with the fibres oriented at 0° and 0°/90° to the specimen axis, where the lay-up is symmetrical and balanced about the specimen mid-plane. The method is suitable for determining shear properties in both the linear and nonlinear load-deformation range even at shear strains greater than 5 %. Short and long fibre-reinforced plastic composites can also be tested using this document.

This document specifies a flexural test method for determining the through-thickness (out-of-plane) tensile properties of laminated carbon fibre-reinforced plastic (CFRP) composites, including strength, fracture strain, and modulus. This document is applicable to unidirectional CFRP (UD-CFRP) laminates. In addition, the calculation of effective volume is also described due to size effects of the through-thickness tensile strength.

ISO 30012:2016 specifies test methods for measurement of the size and aspect ratio of crushed carbon-fibre-reinforced plastics (CFRP), especially for recycling purpose. In this International Standard the shape of crushed CFRP, the fragment, is treated as a rectangular shape, and the measurement of the long and short sides of the shape is described. It applies to fragments of the following average dimensions: - length of the long side: 5 mm to 50 mm; - width of the short side: 1 mm to 10 mm. ISO 30012:2016 provides three measuring methods, two methods are manual methods using microscope and scale and the third method is an automatic method using a measuring apparatus. Crushed CFRP obtained from thermosetting or thermoplastic resin matrices are covered by this International Standard. NOTE If the crushed CFRP contain a lot of small fragments and fine particle, it is intended to screen out by a sieve of 1 mm size before the measurement.

ISO 15114:2014 specifies a method for the determination of mode II shear load delamination resistance. GIIC, (critical energy release rate), of unidirectional fibre-reinforced plastic composites using the calibrated end-loaded split (C-ELS) test. It is applicable to carbon-fibre and glass-fibre reinforced thermosets and thermoplastics. The scope is not necessarily limited to these fibres and lay-ups, but for laminates with other types of fibres or lay-ups, no recommendations for specimen dimensions and fibre volume content are currently available.

ISO 12817:2013 specifies the test method to determine the open-hole compressive strength of laminated fibre-reinforced plastic composites. The laminate is intended to be a balanced and symmetrical lay-up or be otherwise homogeneous through the thickness. ISO 12817:2013 applies to all textile diameter fibre types (carbon, glass, aramids, etc.) and matrices (e.g. thermoset, thermoplastic) that meet its requirements. ISO 12817:2013 includes three methods: method 1 (short specimen with support fixture); method 2 (short specimen without support fixture); method 3 (long specimen with support fixture as in ASTM D 6484M-09, methods A and B).

This International Standard specifies a procedure for determining the plain-pin bearing strength of fibre-reinforced plastic composites. The method described in this International Standard is applicable to fibre-reinforced plastic composites with either thermoset or thermoplastic matrices.

ISO 18352:2009 specifies a method for determining the residual compression strength of multidirectional polymer matrix composite laminate plates that have been damaged by impact prior to the application of in-plane compressive loading. The test method is suitable for continuous-fibre-reinforced polymer matrix composites. Application of the method is limited to fibre-reinforced plastic laminates with multidirectional reinforcements manufactured from unidirectional prepreg tapes/fabrics or woven fabrics. The test method is referred to as the compression-after-impact (CAI) test when used to determine the residual compression strength of an impacted plate. It can be used to obtain data for material specification, material evaluation, research and development, or construction of a composite database.

ISO 14127:2008 specifies methods for calculating the resin, fibre and void contents of a carbon-fibre-reinforced composite from the densities of the resin, the fibre and the composite and the mass of fibre in the composite (method A) and for calculating the fibre content from the thickness of the composite (method B). Method A specifies three different resin removal procedures for the determination of the mass of fibre in the composite (viz a combustion procedure, a procedure by digestion in nitric acid and a procedure by digestion in a mixture of sulfuric acid and hydrogen peroxide). The selection of the procedure to be used is made by considering the combustibility of the resin used in the composite, its ability to decompose and the type of resin concerned. It should be noted that method A is only of limited applicability when filled resins are present that could prevent complete dissolution and/or combustibility of the resin. Method B (thickness measurement method) is only applicable to laminates moulded from prepregs of known fibre mass per unit area.

ISO 1268-4:2005 describes the preparation of test plates from layers of preimpregnated unidirectional fibre or fabric (prepregs) under pressure and temperature in various types of equipment (for example, autoclave, bladder press, hydraulic press or vacuum bag equipment). It applies to all reinforcements and resins. This method is applicable to reinforcements preimpregnated either with a partially cured thermosetting resin or with a thermoplastic resin. The test plate is formed by stacking layers of the preimpregnated material in the required sequence and orientation, followed by compaction and final consolidation under pressure/vacuum at a temperature above ambient. The prepared test plates are subsequently machined into the required test specimens. Standard plates prepared in this manner may be used either for evaluating the components, i.e. the reinforcement, finish, resin, etc., or for verifying the overall quality of the finished product.

ISO 1268-10:2005 specifies the general principles to be followed while injection moulding test specimens of bulk moulding compound (BMC) and gives details of mould designs for preparing one type of specimen for use in establishing reproducible moulding conditions. Where appropriate, this part of ISO 1268 may be applied to sheet moulding compound (SMC) formulated for injection moulding. Its purpose is to promote uniformity in describing the main parameters of the moulding process and also to establish uniform practice in reporting moulding conditions. The particular conditions required for the reproducible preparation of test specimens which will give comparable results will vary for each material used. These conditions are given in the International Standard for the relevant material or are to be agreed upon between interested parties.

ISO 1268-11:2005 specifies two two-cavity moulds, designated the type D1 and type D2 ISO moulds, for the injection moulding of small plates measuring 60 mm by 60 mm with preferred thicknesses of 2 mm (type D1) or 4 mm (type D2) which can be used for a variety of tests. The moulds may additionally be fitted with inserts for studying the effects of weld lines on the mechanical properties.

ISO 1268-8:2004 specifies the general principles and procedures for the compression moulding of test plates from two types of fibre-reinforced thermosetting moulding compound: sheet moulding compound (SMC) and bulk moulding compound (BMC). Two different methods are given for preparing the mould charge: method A for moulding without the material flowing in the mould and method B for moulding so that the material flows in the mould.

ISO 13003:2003 defines the general procedures for fatigue testing of fibre-reinforced plastic composites under cyclic loading conditions of constant amplitude and constant frequency.

ISO 3597-4:2003 specifies a method for determining the apparent interlaminar shear strength of composite rods of circular cross-section made of roving-reinforced resin. The test may be carried out on "as-moulded" rods, or on rods that have been pretreated by immersion in boiling water (or another medium) for a specified time. The test is intended for inspection and quality control of rovings or for evaluating their suitability for use in a resin system. The results obtained are not intended for the generation of design data.

ISO 3597-3:2003 specifies a method for determining the compressive strength of composite rods of circular cross-section made of roving-reinforced resin. The test may be carried out on "as-moulded" rods, or on rods that have been pretreated by immersion in boiling water (or another medium) for a specified time. The test is intended for inspection and quality control of rovings or for evaluating their suitability for use in a resin system. The results obtained are not intended for the generation of design data.

ISO 3597-2:2003 specifies a method for determining the flexural strength of composite rods of circular cross-section made of roving-reinforced resin. The test may be carried out on "as-moulded" rods, or on rods that have been pretreated by immersion in boiling water (or another medium) for a specified time. The test is intended for inspection and quality control of rovings or for evaluating their suitability for use in a resin system. The results obtained are not intended for the generation of design data.

ISO 3597-1:2003 provides general information and specifies a method for preparing specimens (rods) intended to be used for tests specified in the other parts of ISO 3597.

ISO 17771:2002 specifies a method for determining the degree of wetting of the reinforcement in a sheet moulding compound (SMC). It is applicable to quality control by the user of the SMC, as well as to process control during SMC production.

ISO 1268-9:2003 specifies a method for preparing test plates by compression moulding of reinforced thermoplastic sheet (GMT/STC) to be used for the preparation of test specimens to determine the mechanical and physical properties of the laminate. The proposed method is applicable to laminates made from a thermoplastic matrix reinforced with glass, carbon, aramid or other reinforcing fibres, alone or in combination and in any form suitable for compression moulding.

This part of ISO 1268 specifies a pultrusion-moulding method for preparing reinforced plastics test plates to be used for the preparation of test specimens to determine the mechanical and physical properties of the laminate. The method is applicable to laminates made from thermosetting or thermoplastic resins reinforced with glass, carbon or aramid fibres alone or in combination and in any form suitable for the pultrusion process (continuous rovings, tows, mats, fabrics or combinations of these). This part of ISO 1268 is intended to be read in conjunction with ISO 1268-1.

The various parts of ISO 1268 (see the foreword) describe methods used to prepare reinforced-plastics plates from which test specimens can be cut. This allows the properties of a composite, or the constituents of the composite, to be determined. The methods are intended to cover all the main types of reinforcement and resin matrix. The choice of test plate preparation method depends on: a) the reinforcement:  its nature (glass, carbon, aramid, etc.);  its form (roving, mat, woven fabric, etc.);  its orientation with respect to the length, width and thickness of the plate;  its content in the reinforced plastic; b) the matrix (thermosetting or thermoplastic); c) the magnitude expected for the properties; d) the production process that is to be evaluated. Since the mechanical properties of a reinforced plastic are known to be dependent on the process by which the plastic is produced, it is recommended that the test plates be prepared, if possible, by the same method that will be used to produce the plastic. This part of ISO 1268 describes the general requirements common to all the methods.

1.1 This International Standard specifies a method for determining the in-plane shear modulus (G12) of fibrereinforced plastic composites using a standard plate specimen. When applied to isotropic materials, the shear modulus measured is independent of direction. 1.2 The method is used to determine the shear modulus of the test specimens but not to determine the shear strength. It applies to a plate supported on two points on one diagonal and loaded on the other diagonal by the simultaneous movement of two loading points attached to a cross-beam. 1.3 The method is suitable for use with fibre-reinforced plastic composites with both thermoset and thermoplastic matrices. Due to the shear deformation being applied under flexural conditions, for laminated materials with different fibre formats and/or different orientations, the layers of material must be well distributed across the section so that it is approximately "homogeneous" in the through-thickness direction. The principal material axes, if present, must be orientated normal to the plate edges (see 3.8). NOTE This method can be applied to unreinforced polymers and other materials (e.g. metals, ceramics and metal- or ceramic-matrix composites). For material fabricated using unidirectional plies, the shear modulus obtained using a multidirectional specimen (i.e. 0°/90°/_ 45°) is not the same as that obtained for unidirectional or cross-ply (0°/90°) material. 1.4 The method is performed using specimens which may be moulded to the chosen dimensions, machined from test plates or machined from flat areas of products. 1.5 The method specifies preferred dimensions for the specimen. Tests which are carried out on specimens of other dimensions, or on specimens which are prepared under different conditions, may produce results which are not comparable. Other factors, such as the speed of testing and the conditioning of the specimens, can influence the results. Consequently, when comparative data are required, these factors must be carefully controlled and recorded. NOTE The stress-strain response in shear is very non-linear at higher strain levels. This test method determines the modulus within a low strain region and is not applicable to higher strains.

Defines the essential elements which must be present in a method and also those which shall not be included but which the operator must find in other documents, for example, the specification of the product being tested. Also proposes some important definitions in the field of sampling and also in relation to the different results which are generated by the method.

Establishes a list of properties and the corresponding test methods that permit inspection control of thermosetting plastics reinforced with textile glass.

The apparent volatile-matter content is the percentage of matter lost on heating, relative to the initial mass, The principle of the method specified is obtaining it by measuring the change in mass of a test specimen when heated in an air-ventilated oven at a specified temperature for a specified length of time. The method is applicable to all unidirectional and multidirectional fibre-reinforced prepregs and all thermosetting-resin matrices. Does not apply to unimpregnated reinforcement fibres.