مدلسازی عددی نفوذ پرسرعت در چندلایه های بافته شده با درنظرگیری اثرات نرخ کرنش در تخریب پیش رونده

In this research, progressive damage of woven composite materials due to high velocity impact is investigated via finite elements method. Necessity of impact analysis of composite materials using progressive damage method is detailed and available material models for this type of analysis is discussed. Governing equations at onset of failure and failure modes as well as damage growth is expressed. Stain rate effects are contained in dynamic modulus and strength of composite materials. A user defined material model was supplied in LS-DYNA. Different failure modes such as axial failure in fibers due to tension or compression, in-plane lateral and shear failure, out of plane failure and delamination and crushing may be simulated. Ballistic impact in four and eight layered composite targets is investigated using this UMAT. Variation of projectile velocity in terms of time is studied on velocities less than and more than ballistic limit velocity. Two different responses are achieved by considering or neglecting strain rate effects. Also, variation of elastic modulus and strength in fiber direction as function of strain rate and damage growth is investigated for near field, far field and midrange of impact zone.