Why interface testing by single-fibre methods can be misleading

摘要: Abstract The reasons for our interest in the interface are reviewed, and bond-strength sensitive properties discussed. It is shown that four direct methods currently used measurement have problems make their results inconsistent between inaccurate. failure process has been monitored glass/epoxy pull-out specimens with very short fibre free lengths, so crack propagation stable. This showed that, close to ultimate failure, a small length of was carrying nearly all (very high) load. apparently high interfacial shear strength can be explained on basis recently documented lack mode most polymers. All tests centro-symmetric, or so. In this situation, matrix cannot fail shear, must tension. Yet tensile strongly inhibited by centro-symmetry. Hence forced at itself tensile-type process. involves pulling polymer over points fibre. (No surface perfectly smooth.) result thus unduly influenced roughness shrinkage pressure, neither which directly related adhesion. Although great progress made fracture analysis resolve problem unrealistic centro-symmetry tests. is, therefore, recommended instead composites examined relevance usefulness. useful method may well measure off-axis unidirectional composites. more than both fragmentation test test. Single-fibre analyses these should only basic research into centro-symmetric modes.