🔩 Determination of tensile strength, modulus of elasticity, Poisson’s ratios and the stress–strain relationship of composites with thermoplastic or thermosetting matrix (including prepregs) unidirectionally reinforced with carbon, glass, aramid or similar fibres — according to the principles of ISO 527-1, type A specimen (along the fibres, width 15 mm, thickness 1 mm) or type B (transverse to the fibres, 25 mm, 2 mm), length at least 250 mm, distance between end tabs 150 mm, tabs 0,5–2 mm, micrometer 0,01 mm, PN-EN ISO 527-5

Materials and NDT PN-EN ISO 527-5

Overview

WHAT THE STANDARD COVERS. We read the text of the standard in the iTeh sample of ISO 527-5:2021 (English text): from the title page through the contents, foreword and Clauses 1–5 to 6.4 (checking the specimens) on page 7 inclusive. Outside the sample remain the number of specimens (7), conditioning (8), test procedure (9: atmosphere, dimensions, clamping, prestresses, extensometers and strain gauges, speed, recording), calculation (10), precision (11), test report (12) and Annexes A (alignment of specimens), B (unbonded tabs and tab-less specimens) and C (preparation of type A and B specimens, normative).

ACCORDING TO THE TEXT OF ISO 527-5:2021 (foreword, Clauses 1–6.4). The standard was prepared by ISO/TC 61 “Plastics”, Subcommittee SC 13 “Composites and reinforcement fibres”, in collaboration with CEN/TC 249 “Plastics” (Vienna Agreement). The third edition replaces the second (ISO 527-5:2009) as a technical revision; main changes: the gripping force or pressure (e.g. via torque or manometer, depending on the gripping system) has been adjusted, and a new Annex B (unbonded tabs and conditions for gripping tab-less specimens using fine grip faces) has been added. Scope (1): conditions for determining the tensile properties of unidirectional fibre-reinforced plastic composites, based on the general principles of ISO 527-1; according to the note isotropic and orthotropic reinforced materials are covered by ISO 527-4; the methods are used to investigate the tensile behaviour of specimens and to determine strength, modulus of elasticity, Poisson’s ratios and other aspects of the stress–strain relationship; the method is suitable for all polymer matrix systems reinforced with unidirectional fibres which meet the requirements of the document, including failure mode; it covers thermoplastic and thermosetting matrices, including prepregs, carbon, glass, aramid and similar fibres, unidirectionally aligned fibres and rovings, and unidirectional fabrics and tapes; it is not normally suitable for multidirectional materials composed of unidirectional layers at different angles (ISO 527-4). References (2): ISO 527-1:2019, ISO 1268 (all parts — production of test plates), ISO 2818 (preparation of specimens by machining), ISO 16012 (linear dimensions of specimens). Terms (3, mostly from ISO 527-1:2019): gauge length L0, thickness h, width b1, test speed (rate of separation of the jaws, mm/min), stress σ (σ1 for type A specimens, σ2 for type B), strength σm, strain ε and strain at strength εm, modulus of elasticity in tension — slope of the σ(ε) curve between ε′ = 0,05 % and ε″ = 0,25 %, calculated as chord modulus or as the slope of a regression line (E1 for type A, E2 for type B; according to the note the definition does not apply to films), Poisson’s ratio μ — negative ratio of the strain change in a normal axis to the strain change in the direction of extension in the linear portion of the curve (μ12 — major, for type A specimens; μ21 — minor, for type B), specimen axes: “1” — parallel to the fibres (0°, longitudinal direction), “2” — perpendicular to them in the plane of the fibres (90°, transverse direction). Principle (4): according to ISO 527-1:2019, Clause 4. Apparatus (5): according to ISO 527-1:2019, Clause 5, except that the micrometer (ISO 16012:2015, 5.5) shall read to 0,01 mm or better, with a ball-ended anvil on irregular surfaces and a flat anvil on smooth ones; grip pressure shall only prevent the specimen slipping up to failure, since excessive pressure may crush the specimen because of the low transverse strength of these materials; hydraulic grips with constant grip pressure are preferred; with strain gauges bonded to the specimen the error from the transverse effect on the transverse gauge is generally much larger for anisotropic composites than for metals, and accurate measurement of Poisson’s ratio requires correction for this effect; alignment of the specimen and loading train is recommended to be checked according to Annex A. Specimens (6): type A — testing along the fibres, type B — transverse, both with end tabs; both types may also be used with unbonded tabs or without tabs using fine grip faces and careful control of the gripping force (Annex B); to decide whether to use bonded tabs, specimens are first tested without them, and only if almost all break in the grips are specimens with bonded end tabs used; if the material cannot be made in the recommended thickness for unavoidable reasons (e.g. higher area weight, pultrusion), the nearest possible thickness is chosen. Dimensions (Figure 3): overall length ≥ 250 mm, distance between tabs 150 ± 1 mm, width 15 ± 0,5 mm (type A) and 25 ± 0,5 mm (type B), thickness 1 ± 0,2 mm (type A; 2 ± 0,2 mm for specimens from filament-wound plates) and 2 ± 0,2 mm (type B), extensometer gauge length recommended 50 ± 1 mm, nominal grip distance 136 mm, tab length > 50 mm, tab thickness 0,5–2 mm; sides of each specimen parallel to within 0,2 mm; for specimens from filament-wound plates according to ISO 1268-5 a length of 200 mm with 25 mm tabs is acceptable. Preparation (6.2): test plate according to the relevant part of ISO 1268 or another agreed procedure, from which specimens or groups of specimens are cut (Annex C); from finished products — from flat areas; specimen axis within 0,5° of the mean fibre axis; machining parameters according to ISO 2818; specimen ends are reinforced with end tabs, preferably of cross-ply or fabric glass-fibre/resin laminate with fibres at ±45° to the specimen axis, thickness 0,5–2 mm, tab angle 90° (not tapered); other arrangements (tabs of the material under test, mechanically fastened, unbonded tabs of rough materials, e.g. emery paper, fine grip faces without tabs) are permissible if shown before use to give at least equal strength and no greater coefficient of variation than the recommended tabs; for untabbed specimens the grip distance shall be the same as the tab distance, and the contact at the edge of the grip faces needs care; tabs are bonded with a high-stretch adhesive according to Annex C. Gauge marks (6.3) and checking of specimens (6.4) — according to ISO 527-1:2019.

STATUS (as of 03.10.2026). The PKN search (term “PN-EN ISO 527-5”, 03.10.2026) shows PN-EN ISO 527-5:2022-06 (English version, “Introduces: EN ISO 527-5:2021 [IDT], ISO 527-5:2021 [IDT]”) without a withdrawal note and the withdrawn PN-EN ISO 527-5:2010 (Polish version, replaced by PN-EN ISO 527-5:2022-06), PN-EN ISO 527-5:2009 (English version) and PN-EN ISO 527-5:2000 (Polish version). In the iTeh catalogue (read on 03.10.2026) ISO 527-5:2021 has the status “Published”, stage 60.60 (standard published) since 24.11.2021.

HOW MANY LABORATORIES AND IN WHAT FORM (copy of the accreditation scope database, load up to 17.09.2026, read on 03.10.2026). The number 527-5 appears in 6 records at 5 laboratories: AB 001, AB 005, AB 067, AB 163, AB 1490. In the current PCA documents (read on 03.10.2026, issues from 17.12.2025 to 27.07.2026) the number appears in 6 rows: one each at AB 001, AB 005, AB 067 and AB 1490 and two at AB 163 (strength, yield point and elongation; modulus of elasticity); in each of the five documents the number of page markers equals the number of PDF pages, without repetitions; a search of all 1291 PCA documents downloaded from BIP on 03.10.2026 found no laboratories outside the database copy (17 laboratories on the list have no link to a scope document on BIP). The form “PN-EN ISO 527-5:2022-06” (AB 001, AB 005, AB 067, AB 163) and “PN-EN ISO 527-5” without year (AB 1490); always in one cell with other parts of PN-EN ISO 527. None of these items is suspended. The “Laboratories” tab (term “PN-EN ISO 527-5”) shows 3 laboratories: AB 001, AB 067 and AB 163; AB 005 and AB 1490 are under “PN-EN ISO 527-1”, because that designation comes first for them — checked with tab queries on the production server labcoda.pl on 03.10.2026.

WHAT THE LABORATORIES TEST (items in PCA). Object: plastics, plastic composites (AB 001), plastics, polymer composites, rubber, plastic pipes (AB 005), electrotechnical materials and products (AB 067), pipes, fittings and other plastic products (AB 163), composites (AB 1490, item in the flexible scope of accreditation). Characteristics: yield point, stress at break, tensile strength, relative elongation at yield and at break, modulus of elasticity in the load range (0,02–400) kN (AB 001); tensile strength and relative elongation at break, modulus of elasticity in tension, maximum load 300 kN, elongation up to 800 % (AB 005); mechanical tensile, compressive and flexural strength at (20–250) °C, tension and compression up to 100 kN (AB 067); tensile strength, yield point, relative elongation and modulus of elasticity in tension, maximum load 100 kN (AB 163); tensile strength, Young’s modulus, Poisson’s ratio in the force range (0–200) kN and temperatures from −55 °C to +149 °C, static tensile test, also of open-hole specimens (AB 1490, together with ASTM D3039/D3039M and ASTM D5766/D5766M).

WHERE A SEEMINGLY CORRECT RESULT IS EASY TO GET. With the choice of specimen: type A only along the fibres, type B only transverse; specimen axis within 0,5° of the fibre axis (6.1, 6.2). With clamping: excessive grip pressure crushes the specimen, too little causes slipping (5). With tabs: first tests without bonded tabs, and alternative tabs only after showing equal strength and no greater scatter (6.1.1, 6.2). With thickness: 1 mm for type A, 2 mm for type B and for specimens from filament-wound plates (6.1). With Poisson’s ratio: bonded strain gauges require correction for the transverse effect (5). With the modulus: strain interval 0,05–0,25 % (3.7). With the material: multidirectional laminates of unidirectional layers are tested according to ISO 527-4, not this part (1).

WHAT WE DO NOT GIVE. We did not read the number of specimens, conditioning, the test procedure (including speed), formulae, precision or the content of the report (Clauses 7–12), nor Annexes A–C. We do not give strength values for particular composites.

Method principle

A rectangular specimen of unidirectional fibre composite — type A cut along the fibres or type B transverse, with ends reinforced by tabs — is stretched in a tensile testing machine according to the principles of ISO 527-1, recording force and strain. From the stress–strain curve the strength, strain at strength, modulus of elasticity (slope between 0,05 % and 0,25 %) and — when transverse strain is measured — Poisson’s ratio μ12 or μ21 are determined.

Applications

• Composites with thermoplastic and thermosetting matrix, including prepregs, unidirectionally reinforced with carbon, glass, aramid or similar fibres (1)
• Unidirectionally aligned fibres and rovings, unidirectional fabrics and tapes; specimens from test plates according to ISO 1268 and from flat areas of finished products (1, 6.2)
• Plastics, composites, plastic products and electrotechnical materials — items in the accreditation scopes of 5 laboratories in PCA

Key parameters

Standard

Standard number

PN-EN ISO 527-5:2022-06

Title (PL)

Tworzywa sztuczne — Oznaczanie właściwości przy rozciąganiu — Część 5: Warunki badania kompozytów tworzywowych wzmocnionych jednokierunkowo włóknem

Title (EN)

Plastics — Determination of tensile properties — Part 5: Test conditions for unidirectional fibre-reinforced plastic composites

Step-by-step procedure

1. Plate and specimens

   Plate according to ISO 1268 or an agreed procedure; cutting type A or B specimens, axis within 0,5° of the fibres (6.2). PN-EN ISO 527-5:2022-06 without a withdrawal note (03.10.2026).

2. End tabs

   First tests without bonded tabs; if almost all specimens break in the grips — bonded tabs according to Annex C (6.1.1, 6.2.3).

3. Measurement and checking

   Dimensions with a 0,01 mm micrometer, gauge marks and checking of specimens according to ISO 527-1 (5, 6.3, 6.4).

4. Tensile loading

   Clamping without slipping or crushing, recording of force and strain; procedure according to Clause 9 (not read).

5. Result

   Strength, strain, modulus from the 0,05–0,25 % interval, Poisson’s ratio; calculation and report according to Clauses 10–12 (not read).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Brittle failure of the composite under load — fragments and fibres; guards and eye protection
• Cutting and grinding composites — fibre dust; extraction and respiratory protection

Frequently asked questions