MARC有限元收敛性问题及程序退出代码说明详解.ppt

Nonlinear Analysis Guidelines Nonlinear Analysis Guidelines Analysis Messages Analysis Messages The Status File… Summary of the convergence behaviour of the analysis… Things to look out for: Sudden jumps in the number of cycles (what happened?) Large number of separations throughout (a general contact issue) Large number of separations part way (contact lost? Contact causing local failure? Frictional forces overcome?) Large number of cut-backs throughout (load increment too large) Large number of cut-backs part-way (what happened?) Getting Clues… Post process what there is… The deformed shape often gives obvious clues as to why the simulation is not converging Exaggerating the deformation is a good way to pick up cracks in the model or localised effects from incorrect contact definition Animating with a reasonable deformation exaggeration can also be of help If convergence is not achievable in the first increment it can be very helpful to specify that Marc continues “proceed when not converged” option This means that a POST results file will be generated Even if an increment fails to converge it may provide a pointer to the problem General… Contact Contact Contact Hyperelastic Material Data Include Reality Specify a mesh so that the shape of the elements is reasonable throughout the entire analysis Anticipate how the mesh will deform For example, make element sides shorter in the direction that will be elongated the most General… Convergence Criteria Behaviour Convergence Criteria Behaviour Convergence Criteria Behaviour Convergence Criteria Behaviour Convergence Criteria Behaviour Convergence Criteria Behaviour Convergence Criteria Behaviour Convergence: EXIT 2004 Convergence: EXIT 2004 Convergence: EXIT 2004 Convergence: EXIT 2004 Convergence: EXIT 2004 Convergence: EXIT 2004 Convergence: EXIT 2004 Convergence: EXIT 1005/1009 Convergence: EXIT 1005 Convergence: EXIT 1005 Convergence: EXIT 1005 Convergence: EXIT 1005 Any Kkk(k) Are Zero (Zero Pivot) Indicate