ISO 13094:2025

International
Standard
ISO 13094
First edition
Composites and reinforcement
2025-04
fibres — Carbon fibre reinforced
plastics (CFRPs) and metal
assemblies — Combined stress test
Composites et fibres de renfort — Assemblages de plastiques
renforcés de fibres de carbone (CFRP) et de métal — Essais sous
contraintes combinées
Reference number
© ISO 2025
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3  Terms and definitions . 1
4 Principle . 3
5 Apparatus . 3
5.1 Combined loading fixture .3
5.2 Tensile testing machine .5
6 Test specimen . 5
7 Conditioning . 6
8 Test procedure . 6
9 Calculation of loads and stresses . 6
10 Test report . 8
Annex A (informative)  Example of test fixture for combined stress test . 9
Annex B (informative)  Example of combined stress test on Metal/CFRP adhesive bonded
assembly . 10
Bibliography .12

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 13, Composites
and reinforcement fibres.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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iv
Introduction
This document provides a test method for producing a well-controlled combined stress state in plane-stress
conditions. This methodology can provide an accurate means for evaluating the strength of bonded metal-
composite assemblies that depends only on the interaction between dissimilar adherend, the adhesive,
and the interfaces subjected to various combined loadings. The results can be used to create the failure
envelope for metal-composite assemblies for use in the design optimization of metal-composite assemblies.
[1]
The original fixture was designed to study the shear properties of polymers and later modified to perform
[2],[3]
combined load tests for various materials, including bonded assemblies of dissimilar materials.
This document is intended to provide experimental apparatus, test procedures, and manipulation of the
result for determining the strength of adhesive-bonded metal-CFRP-metal assemblies under combined
loading conditions.
v
International Standard ISO 13094:2025(en)
Composites and reinforcement fibres — Carbon fibre
reinforced plastics (CFRPs) and metal assemblies —
Combined stress test
1 Scope
This document specifies the test method used to determine the strength of the adhesive-bonded carbon fibre
reinforced plastics (CFRP) to metal assemblies under combined loading conditions. The loading fixture, a
standard specimen, and procedure for combined shear and normal load tests under plane stress conditions
are provided. The test method is also applicable to bonded joints between metals and other composite
materials, including glass fibre-reinforced plastics.
This document does not cover specimen preparation of the adhesive joint.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1:
Tension/compression testing machines — Calibration and verification of the force-measuring system
ISO 10365, Adhesives — Designation of main failure patterns
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
applied load
F
force applied in the loading axis that causes simultaneous shear and normal stresses on the bonded area
Note 1 to entry: See Figure 1.
3.2
maximum applied load
F
max
highest value of force observed in the applied load-displacement curve
Note 1 to entry: See Figure 4.

3.3
loading angle
α
angle between the loading axis and
...