Effectiveness of Pinball Impact-Contact Algorithms for Plate Elements

This paper presents an evaluation of several implementations of the pinball impact-contact algorithm for plate elements. Because the thickness of a plate element is much smaller than the other dimensions, a single pinball as is commonly done with hexahedral elements cannot be used to accurately detect contact over the entire plate surface. Since the pinballs are spheres, contact between pinballs of impacting plate elements may not lie along the normal direction to the contacting plates. Multiple pinballs must be defined in each plate element to accurately capture the time of impact and the direction of the impact force. A reduced splitting pinball method and variants of the direct localization method are proposed to reduce computational time for plate/shell impact problems. To evaluate computational efficiency and accuracy in detecting initial contact and the direction of the contact force, several schemes were evaluated. The NEPTUNE finite element code, which is based on explicit time integration, was used as the computational engine in this study.