ISO 18352:2009

Carbon-fibre-reinforced plastics — Determination of compression-after-impact properties at a specified impact-energy level

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.

Plastiques renforcés de fibres de carbone — Détermination des propriétés de compression après impact à un niveau d'énergie spécifié

General Information

• Status: Published
• Publication Date: 06-Aug-2009
• ICS: 83.120 - Reinforced plastics
• Technical Committee: ISO/TC 61/SC 13 - Composites and reinforcement fibres
• Drafting Committee: ISO/TC 61/SC 13/WG 2 - Laminates and moulding compounds
• Current Stage: 9020 - International Standard under periodical review
• Start Date: 15-Jul-2025
• Completion Date: 15-Jul-2025

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 18352
First edition
2009-08-15
Carbon-fibre-reinforced plastics —
Determination of compression-after-
impact properties at a specified
impact-energy level
Plastiques renforcés de fibres de carbone — Détermination des
propriétés de compression après impact à un niveau d'énergie spécifié

Reference number
©
ISO 2009
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©  ISO 2009
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ii © ISO 2009 – All rights reserved

Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Principle. 3
5 Conditioning of specimens and test environment . 4
5.1 Standard conditioning procedure for specimens . 4
5.2 Environmental test chamber for impact and compression tests . 4
6 Test apparatus . 4
6.1 General. 4
6.2 Impact facility. 4
6.3 Support fixture for specimen. 4
6.4 Non-destructive testing instrument. 6
6.5 Compression-testing machine . 6
6.6 Compression-loading fixture. 6
6.7 Measuring apparatus. 7
6.8 Strain gauges . 8
7 Specimens . 8
7.1 Dimensions. 8
7.2 Specimen preparation . 9
7.3 Number of specimens . 10
8 Procedure . 10
8.1 Specimen conditioning . 10
8.2 Measurement of specimen dimensions. 10
8.3 Impact test . 10
8.4 Non-destructive testing (NDT). 11
8.5 Inspection of specimens. 11
8.6 Compression test. 11
9 Validation. 13
10 Calculation of results . 14
10.1 CAI strength . 14
10.2 CAI modulus. 15
10.3 Maximum CAI strain . 15
10.4 Rounding the results. 15
10.5 Standard deviation and coefficient of variation . 15
11 Test report . 16
Annex A (normative) Detailed drawings of the components of the compression-loading fixture . 17
Bibliography . 20

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 18352 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 13, Composites
and reinforcement fibres.
iv © ISO 2009 – All rights reserved

INTERNATIONAL STANDARD ISO 18352:2009(E)

Carbon-fibre-reinforced plastics — Determination of
compression-after-impact properties at a specified
impact-energy level
1 Scope
This International Standard 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.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 291, Plastics — Standard atmospheres for conditioning and testing
ISO 1268-4:2005, Fibre-reinforced plastics — Methods of producing test plates — Part 4: Moulding of
prepregs
ISO 5893, Rubber and plastics test equipment — Tensile, flexural and compression types (constant rate of
traverse) — Specification
ISO 14127, Carbon-fibre-reinforced composites — Determination of the resin, fibre and void contents
1)
ISO 80000-1:— , Quantities and units — Part 1: General

1) To be published. (Revision of ISO 31-0:1992)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
compression-after-impact test
CAI test
in-plane compression test undertaken on a composite laminate loaded in the plane of the laminate, after
applying an out-of-plane concentrated impact load under defined conditions
3.2
specified impact energy
potential energy of the drop-weight, specified by the mass and drop height of the indenter, to which composite
laminate specimens will be subjected, expressed in joules
3.3
barely visible impact damage
BVID
impact damage corresponding to a dent depth of 0,3 mm
3.4
energy to cause BVID
E
BVID
impact energy required to cause BVID, expressed in joules
3.5
compression-after-impact strength
σ
CAI
maximum compressive load sustained by the impacted specimen divided by the initial cross-sectional area of
the specimen, expressed in MN/m
3.6
compression-after-impact modulus
E
CAI
compression modulus of the specimen calculated between 0,05 % and 0,25 % strain, expressed in GN/m
3.7
maximum compressive strain
ε
cmax
maximum value of the compressive strain sustained by the specimen at the maximum compressive load
3.8
dent depth
residual depth of the depression formed by the indenter after the impact event, expressed as the maximum
distance, in millimetres, in a direction normal to the face of the specimen from the lowest point in the dent to
the plane of the undisturbed impact surface
3.9
damage parameters
quantities used to characterize the extent of impact damage, including the maximum diameter of the
delamination and the projected area of the delamination
2 © ISO 2009 – All rights reserved

4 Principle
The CAI test detailed in this International Standard consists of three phases as depicted in Figure 1.
The first phase is to generate barely visible impact damage (BVID), avoiding penetration of the test plate. The
preferred method of introducing BVID is based on a specified level of impact energy applied to one face of a
specimen made of a balanced and symmetrical composite laminate.
NOTE An alternative method allows the operator to vary the level of impact energy in order to determine the energy
level required to cause BVID. An additional ISO method will be proposed and drafted to cover this method of setting the
impact energy.
The second phase consists of assessing the level of impact damage by non-destructive testing (NDT) [also
referred to as non-destructive inspection (NDI)] and by measurement of the dent depth on the impacted face.
The area and geometry of the damage created by the impact shall be measured by means of an appropriate
non-destructive testing technique, and the dent depth measured by a suitable device.
Measurement of residual in-plane compression properties is undertaken in the third stage. A compressive load
is applied to the impacted specimen until failure occurs. The CAI strength, modulus and strain are calculated
from the load strain data collected, as detailed in Clause 10.

a)  Impact test configuration b)  Non-destructive testing and c)  Compression test
dent depth measurement
Key
1 specimen
2 delamination
3 compressive load, F
Figure 1 — Principle of the compression-after-impact test
A flat, rectangular composite plate is subjected to a transverse, concentrated impact using a drop-weight
device with a hemispherical indenter. The energy of the impact, determined by the mass and drop height of
the indenter, is specified. Equipment and procedures are prescribed for measurement of the contact force and
the inde
...