Brain impact with Alya (part 1)
Alya  is a large scale computational mechanics code developed at the Barcelona Supercomputing center.
A rapid brain impact has been calculated at Idra Simulation using Alya. The mesh used is the “Colin27 adult brain atlas“ created at Harvard Medical School using iso2mesh, an open-source matlab/octave-based software . iso2mesh creates 3D tetrahedral meshes from images such as MRI and CT scans.
The mesh has 4 different materials: scalp/skull, cerebro-spinal fluid, gray matter and white matters:
This animation shows the displacement of the brain after an oblique impact of 40 ms:
This test is simplified in terms of material properties, but serves as an example to show the explicit mechanics capabilities of Alya.
More about Alya:
 E. Casoni, A. Jerusalem, C. Samaniego, B. Eguzkitza, P. Lafortune, D. D. Tjahjanto, X. Suaez, G. Houzeaux, M. Vázquez. “Alya: computational solid mechanics for supercomputers“. Archives of Computational Methods in Engineering. DOI: 10.1007/s11831-014-9126-8. August 2014
 Qianqian Fang and David Boas, “Tetrahedral mesh generation from volumetric binary and gray-scale images,” Proceedings of IEEE International Symposium on Biomedical Imaging 2009, pp. 1142-1145, 2009