Flat nose low velocity drop-weight impact response of carbon fibre composites using non-destructive damage detection techniques

Abstract

This work is mainly concerned with the nondestructive post-impact damage evaluation of carbonbre reinforced laminated composite panels subject to low velocity drop-weight impact by at and round nose impactors. Quasi-isotropic laminates consisting of eight-, sixteen-, and twenty-four plies were impacted by at and round nose impactors at di erent velocity levels. Load-time history data were recorded and plotted to correlate loaddrop as damage level to the impactor nose pro les. Test produced data, non-destructive damage detection techniques: visual, ultrasonic, and eddy-current, and computer simulations were utilised to identify and quantify status of the impact induced damage. To evaluate damage in relatively thick laminates (consisting of 24-Ply), the damage ratios and de ection quantities were correlated to the corresponding impactor nose pro les. Damage induced by the at nose impactor to thick laminates was compared against the data produced by the round nose impactor. Results show that relatively thin laminates were largely a ected by the impactor nose. Reasonable di erence was observed in damage caused by at and round impactor nose pro les to thick laminates impacted at relatively higher velocity impacts. Results were compared and validated against simulation produced data.

Finite element simulation of carbon fibre-reinforced composite laminates subjected to low velocity impact using damage induced static load-deflection methodology

“…Localisation of an impact damage based on mechanical wave propagation in plate-type structures has been continuously studied. The study has evolved with the use of sensors, signal processing methods, and computing power [1,2,3,25]. The analogy was applied to simulate laminates embedded with pre-assumed zones of specified damage size, location, and type.…”

“…The deflection can also be directly measured in tension or compression to achieve elastic failure due to low shear strength [1]. The methodology also greatly simplifies theoretical analysis as time-dependent terms in the governing equations do not appear and much more data can be obtained [2,3]. The data can be used to correlate various loading parameters to the internal damage modes such as: matrix cracking, delamination, and fibre failures.…”

Finite element simulation of buckling-induced failure of carbon fibre-reinforced laminated composite panels embedded with damage zones

“…The internal damage growth induced buckling instabilities are greatly influenced by through-thethickness location, direction, shape, and size of damage [4]. Similarly, the impact damage of composite panels often is reported to be fairly uniform through-the-thickness that concentrates to a small region of damage width [5]. The smaller or larger size damage areas produce corresponding reductions in buckling strength which leads to a relation between the damage zones and critical buckling load [6], [7] and [8].…”

“…Farooq [23] studied the effect of delamination under axial loading for laminated plates. Yin and Jane [24] conducted the buckling and post-buckling analysis of laminates with elliptic anisotropic delamination.…”