Hello everyone,I am researching the dynamic crack propagation problem using the cohesive element.At this moment, I am using the LS-DYNA (971)software's cohesive material model ,But it does't consider the penetration of bulk elements when the cohesive elements after deleted or not deleted. so the bulk will penetrate each other when under exterior dynamic load. From the literature, I know that many reserachers use the solver which is writern by themselves,and the cohesive element also writen by self. How can some kind expersist give me a tutoial ,Thanks.