ISO 22841:2021

Overview - ISO 22841:2021 (CFRP to metal lap‑shear testing)

ISO 22841:2021 specifies a standardized method to determine the tensile lap‑shear strength of adhesive joints between carbon fibre‑reinforced plastics (CFRPs) and metal adherends. The standard uses a single‑lap specimen loaded in tension under defined preparation, conditioning and testing conditions to assess the suitability of adhesives for bonding CFRP to metal in development, qualification and quality control.

Key topics and technical requirements

• Test principle: Single‑overlap joint is loaded in tension to induce shear in the adhesive layer; failure load is recorded.
• Specimen construction: One CFRP and one metal adherend. Typical nominal thicknesses shown: CFRP t = 3.0 mm ± 0.3 mm; metal t = 3.0 mm ± 0.25 mm. Six specimens are required from prepared panels.
• Preparation & curing: Surfaces may be abraded as agreed; adhesives prepared and cured per manufacturer or client/test lab agreement. Cure time/conditions must be recorded.
• Conditioning: Specimens conditioned in standard atmospheres per ISO 291 or as agreed between parties.
• Apparatus: Accurate linear measuring device (±0.05 mm), tensile testing machine sized so rupture occurs between 10 % and 80 % of load cell capacity, and grips that self‑align. Machine response and force measurement accuracy requirements are specified.
• Test procedure: Specimens loaded so failure occurs within (60 ± 20) s (unless otherwise agreed). Orientation and sequencing of specimens are controlled to reduce bias.
• Results & calculation: Report breaking force (N) and lap shear strength (MPa) = breaking force / shear area (mm²). Express arithmetic mean and standard deviation for valid specimens.
• Test report: Must include full identification of adhesive and adherends, bond/process details, adhesive thickness control, specimen dimensions, conditioning, test speed, individual results, mean, SD, and any deviations.

Applications - who uses ISO 22841:2021

• Adhesive manufacturers for product development and qualification of adhesives for CFRP-to-metal bonding.
• Composite and mechanical engineers evaluating joint performance in aerospace, automotive, marine and sporting goods.
• Materials testing laboratories performing standardized bond strength comparisons and quality control.
• Design and production teams validating bonding processes, surface preparation and cure cycles.

ISO 22841:2021 helps ensure consistent, comparable lap‑shear data to make informed material and process choices for bonded CFRP‑metal assemblies.