Low-velocity impact damage prediction of composite laminates using linearized contact law

Recently, author had presented that impact force history of composite laminates subjected to low-velocity impact could be well analyzed using linearized contact law instead of the modified Hertzian contact law. If the linearized contact law concept is applied in impact response analysis, the impact problem can be transformed as a general structural analysis problem, so general purpose FEM software can be used in this kind of impact response analysis. In the present study it will be shown that impact damage, specially delamination area, as well as impact response can be well analyzed using the linearized contact law concept. In order to accurately predict delamination area, geometrical nonlinear analysis considering large deflection effect of plate has been performed and thermal stress analysis to consider thermal residual strain induced in curing process has been performed. Also, a proper failure criterion for delamination estimation has been used. In this failure criterion, in-situ strength values, obtained through matrix crack onset analysis have been used. Finally, analytically predicted delamination areas have been compared with experimental results. It shows that this analytical procedure can well predict delamination area of composite laminates subjected to the low-velocity impact.