Fatigue testing

Progressive, localised damage caused by repeated or fluctuating loads at stresses below a material's static strength. Fatigue governs the life of components such as wind turbine blades, hulls and airframes, and typically initiates at stress concentrations.

Long-duration testing in which a constant load or stress is applied to a specimen, usually at controlled temperature, while the slow time-dependent deformation is recorded. It is particularly important for polymers, adhesives and membranes, where deformation under sustained load can govern long-term design.

A mechanical test in which a specimen is pulled along its axis until it breaks, measuring properties such as tensile strength, tensile modulus and elongation at break. For plastics and composites it is commonly performed to methods in the ISO 527 series or ASTM D638 and D3039. It is the baseline test for characterising resins, laminates and reinforcement materials.

Mechanical or physical testing of small standardised specimens, known as coupons, cut from a laminate, panel or production sample rather than testing the full component. Coupon results underpin material qualification, design allowables and batch quality control in composites manufacture.