Let’s talk about the failure sequence of carbon fiber specimens! The article »Carbon Fiber Reinforced Polymer and Epoxy Adhesive Tensile Test Failure Analysis Using Scanning Electron Microscopy» has many interesting pictures!
Morphological characteristics analysis before and after tensile tests were studied using scanning electron microscopy (SEM) technique to follow the failure evolution on carbon fiber reinforced polymer (CFRP) and epoxy resins. Micrograph analysis of CFRP plate before tensile test shows some intrinsic manufacturing defects, which can influence the mechanical properties of the material.
Uniaxial tensile tests were performed on fiber direction to investigate how different adhesives affect the failure of the specimens. As you can see, once the stress reaches a certain threshold, cracks start to propagate, matrix debonding occurs, and some fibers start to »pull out». Adhesive and cohesive fracture also happen, until the material fails completely, leaving a rough and serrated surface on the fractured fibers.
Link to the article: https://lnkd.in/eQZHrWB