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A frictional spring and cohesive contact model for accurate simulation of contact forces in numerical manifold method
Author(s) -
Zhang Ning,
Li Xu,
Lin Xingchao
Publication year - 2020
Publication title -
international journal for numerical methods in engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.421
H-Index - 168
eISSN - 1097-0207
pISSN - 0029-5981
DOI - 10.1002/nme.6311
Subject(s) - spring (device) , contact force , convergence (economics) , normal force , manifold (fluid mechanics) , deformation (meteorology) , contact mechanics , shear (geology) , scheme (mathematics) , computer science , structural engineering , mechanics , finite element method , mathematics , engineering , geology , mathematical analysis , mechanical engineering , classical mechanics , physics , economics , economic growth , petrology , oceanography
Summary “Open‐close iteration” is a crucial algorithm for handling complex contacts in numerical manifold method (NMM) and discontinuous deformation analysis (DDA). This algorithm has proved to be robust and efficient for decades. However, as some researchers have pointed out, the original open‐close iteration may involve errors in sliding tests, especially in critical sliding tests with cohesive contacts. In this study, two major problems in the original algorithm are found to be nonconvergent contact force and early removed cohesive strength. The modifications are the following: (a) a frictional spring. By avoiding the trail value of normal contact force, we added a new frictional spring to the iteration scheme. This spring can apply accurate friction and can help ensure the convergence of contact forces. (b) A cohesive contact model. The original scheme can encounter an “early failure” in cohesive contacts. After investigating how contacts provide shear resistance, we found the cause and then provided a simple correction of the cohesive issue. The new algorithms in this article are essential for accurately simulating contacts by NMM/DDA.