Overview
ISO 15108:1998 is an international standard developed by the International Organization for Standardization (ISO) that specifies a procedure for determining the strength of adhesive bonded joints using a bending-shear test method. This standard provides a systematic approach to compare different adhesives based on their resistance to shear deformation under bending stress. It is important to note that the results produced by this test method are intended solely for comparative analysis of adhesives and are not suitable for design or structural engineering purposes.
Key Topics
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Scope and Purpose
ISO 15108:1998 defines a bending-shear test method to evaluate the strength of adhesive joints. The method applies shear stress to the adhesive bond until failure, measuring the maximum load the joint can withstand.
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Test Principle
A bonded joint specimen is subjected to bending-shear stress using a dedicated testing apparatus. The test records the maximum load before the joint fails, which quantifies the adhesive's bonding strength.
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Test Apparatus
The testing setup includes:
- A compression-capable tensile testing machine with controlled movement speed and load measurement accuracy within ±1%.
- A base support and loading piece designed for uniform contact on the test specimen.
- Spacers to adjust for specimen thickness variations.
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Specimen Preparation
- Supports may be made from metal, rigid plastics, fiber-reinforced plastics, wood, or wood derivatives.
- Dimensions and shape of specimens follow precise guidelines to ensure consistent stress application.
- Surface treatment and cleaning per manufacturer recommendations or in accordance with ISO 4588 (metals) and ISO 13895 (plastics).
- Adhesive application and curing are performed following manufacturer instructions, with joint thickness controlled by glass beads or wire spacers.
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Testing Conditions
- Specimens are conditioned under standard atmospheres per ISO 291.
- The loading speed is between 1 mm/min and 100 mm/min, with 10 mm/min recommended.
- At least five specimens are tested to derive an average strength value.
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Result Expression
Bond strength is calculated by dividing the maximum load (Newtons) by the bonded area (mm²), reported in megapascals (MPa).
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Reporting Requirements
Test reports must include detailed identification of adhesives, substrates, joint thickness, conditioning environment, test speed, result data, failure mode per ISO 10365, and the test date.
Applications
ISO 15108:1998 is widely applicable in industries where adhesive bonding is critical, such as:
- Manufacturing: Verifying adhesive performance for quality control in assembly operations involving bonded joints.
- Materials Research: Comparing adhesive formulations and substrate compatibility for product development.
- Automotive and Aerospace: Screening adhesives for bonding strength under bending-shear conditions during preliminary testing phases.
- Construction: Evaluating adhesives used for wood, plastic, and composite bonding where shear performance is relevant.
This standard helps organizations objectively assess and compare adhesive strengths under standardized bending-shear stress, facilitating informed choices in adhesive selection and quality assurance.
Related Standards
- ISO 4587:1995 - Determination of shear strength of rigid-to-rigid bonded assemblies at lap joints, complements ISO 15108 by focusing on different joint geometries and test methods.
- ISO 4588:1995 - Guidelines for surface preparation of metals prior to adhesive bonding, essential for consistent joint quality.
- ISO 10365:1992 - Designation of bond failure types, used in conjunction with ISO 15108 to classify fracture modes observed during testing.
- ISO 291:1997 - Standard atmospheres for conditioning and testing plastics and adhesives, ensuring reproducible environmental conditions.
- ISO 13895:1996 - Surface preparation methods for plastics, critical for achieving reliable bonds tested under ISO 15108.
- ISO 5893:1993 - Testing apparatus specifications for rubber and plastic tensile, flexion, and compression tests, relevant for test machine calibration.
Keywords: ISO 15108, adhesive strength testing, bonded joints, bending-shear method, adhesive joint strength, adhesive testing standard, shear deformation resistance, adhesive bond evaluation, ISO adhesive standards, joint shear strength measurement.