Compression-after-impact response of woven fiber-reinforced composites

Experimental analysis of CFRP laminates subjected to compression after impact: The role of impact-induced cracks in failure

“…But again, this study does not permit to define the nature of this crack, and its origin: fibre failure in compression, or fibre failure due to bending when buckling occurs. Yan et al [8] present the same kind of cracks in glass fabrics, where cracks and delamination propagate together. Post-mortem observations lead him to conclude that they are shear cracks.…”

“…Indeed, among the experimental studies, some focus on the influence of material properties on the evolution of the residual strength: fibre [8,11], resin [11][12][13], interface [14], stacking [15], transverse reinforcement like stitching [16,17] or Z-pinning [18], fabric instead of unidirectional tape [12,19], curing temperature [19]. There are also some experimental studies concerning the influence of test conditions such as: temperature during impact [20], hygrothermal conditions [12,[21][22][23], fatigue loading [24], or use of protective layer [25].…”

“…In recent years, studies on CAI have largely focused on modelling the residual strength with analytical [2,3], semi-empirical [4], or finite elements [5][6][7][8][9][10] approaches, even though the physical mechanisms leading to the final rupture are still not well known today. Indeed, among the experimental studies, some focus on the influence of material properties on the evolution of the residual strength: fibre [8,11], resin [11][12][13], interface [14], stacking [15], transverse reinforcement like stitching [16,17] or Z-pinning [18], fabric instead of unidirectional tape [12,19], curing temperature [19].…”

The influence of toughening-particles in CFRPs on low velocity impact damage resistance performance

“…Of the three damage modes mentioned, delaminations are widely accepted as being responsible for reduced residual compressive strength; wherein the delamination area is reported to correlate with the loss in compression strength [8][9][10]. Delaminations may be considered to create sublaminates with lower in-plane load-carrying capabilities prior to buckling [11,12]. It is therefore desirable to minimise the extent of delaminations by increasing the intrinsic damage resistance of the material.…”

Damage characterization of carbon/epoxy laminates using compression-after-impact (CAI) and ultrasonic NDE

“…An impacted sample is placed under uniaxial compression in a fixture with simple supports on all four edges. Experiments have shown that catastrophic shear failure typically occurs in the form of a crack originating from the impact location and propagating laterally towards the outer edges of the sample [5]. In this paper, unidirectional carbon/epoxy samples were subjected to out-of-plane impact loads using an instrumented drop tower.…”