What you describe is typical of strain softening. In the solid mechanics community, arc length methods are often prefered to solve this kind of problems. The classical references are Riks and Crisfield. You can also take a look at this technique : http://onlinelibrary.wiley.com/doi/10.1002/nme.971/abstract. But I am not aware of the avalability of such approach in the TS objects of PETSc.
Nicolas 2018-01-04 8:35 GMT+01:00 Sanjay Govindjee <[email protected]>: > Are you sure your problem is stable? Also have you tried adding mass? > > > On 1/3/18 10:12 PM, Avtar Singh wrote: > > Hello Petsc Users, > > I am solving a fortran framework to simulate phase-field fracture problem. > Upto the failure point the code is working fine. But as the crack-phase > starts to propagate, there is abrupt changes in the Stiffness Matrix, so > determinant becomes nearly equal to zero. Hence, the code crashes. > > I tried with mumps package with pc lu. Also tried, superlu, gmres and > fgmres with jacobi, bjacobi, lu. But the problem still persist. > > Can anyone suggest, Which solver and preconditioner should i use? > > Thank you > > -- > Avtar Singh > Research Scholar > Multiscale Mechanics and Multiphysics Lab > IIT Roorkee, Roorkee > > >
