Fast approximations for boundary element based brittle fracture simulation

David Hahn, Chris Wojtan
2016 ACM Transactions on Graphics  
Figure 1 : Shooting a heavy sphere at a column (a): as the column breaks, the topmost fragment is pushed upwards into the bunny, whose ears break off close to the smallest cross-section (b). As the remainder of the bunny falls down it hits a sharp edge of a fragment from the column (d) and fractures again (e). The entire fracture simulation for this scene takes just over 16 minutes on commodity hardware. Abstract We present a boundary element based method for fast simulation of brittle
more » ... of brittle fracture. By introducing simplifying assumptions that allow us to quickly estimate stress intensities and opening displacements during crack propagation, we build a fracture algorithm where the cost of each time step scales linearly with the length of the crackfront. The transition from a full boundary element method to our faster variant is possible at the beginning of any time step. This allows us to build a hybrid method, which uses the expensive but more accurate BEM while the number of degrees of freedom is low, and uses the fast method once that number exceeds a given threshold as the crack geometry becomes more complicated. Furthermore, we integrate this fracture simulation with a standard rigid-body solver. Our rigid-body coupling solves a Neumann boundary value problem by carefully separating translational, rotational and deformational components of the collision forces and then applying a Tikhonov regularizer to the resulting linear system. We show that our method produces physically reasonable results in standard test cases and is capable of dealing with complex scenes faster than previous finite-or boundary element approaches.
doi:10.1145/2897824.2925902 fatcat:valgjhcypfhonmjvimyuuuq5zy