TY - EJOU
AU - Bardenhagen, S.G.
AU - Guilkey, J.E.
AU - Roessig, K.M.
AU - Brackbill, J.U.
AU - Witzel, W.M.
AU - J.C.Foster,
TI - An Improved Contact Algorithm for the Material Point Method and Application to Stress Propagation in Granular Material
T2 - Computer Modeling in Engineering \& Sciences
PY - 2001
VL - 2
IS - 4
SN - 1526-1506
AB - Contact between deformable bodies is a difficult problem in the analysis of engineering systems. A new approach to contact has been implemented using the Material Point Method for solid mechanics, Bardenhagen, Brackbill, and Sulsky (2000a). Here two improvements to the algorithm are described. The first is to include the normal traction in the contact logic to more appropriately determine the free separation criterion. The second is to provide numerical stability by scaling the contact impulse when computational grid information is suspect, a condition which can be expected to occur occasionally as material bodies move through the computational grid. The modifications described preserve important properties of the original algorithm, namely conservation of momentum, and the use of global quantities which obviate the need for neighbor searches and result in the computational cost scaling linearly with the number of contacting bodies. The algorithm is demonstrated on several examples. Deformable body solutions compare favorably with several problems which, for rigid bodies, have analytical solutions. A much more demanding simulation of stress propagation through idealized granular material, for which high fidelity data has been obtained, is examined in detail. Excellent qualitative agreement is found for a variety of contact conditions. Important material parameters needed for more quantitative comparisons are identified.
KW - Contact Algorithm
KW - Material Point Method
KW - Wave Propagation
KW - Granular Material
DO - 10.3970/cmes.2001.002.509