Step time calculations

  The following equations are used by the interface to calculate the default step time:

$$K = \frac{E}{3(1-2\nu)}$$ $$c = \sqrt{K/\rho}$$ $$T_{step} = \frac{L_{min}}{c}$$

Where:

E is the Young's modulus of the material
$\nu$ is Poisson's ratio for the material
K is the Bulk modulus of the material
$\rho$ is the density of the material
c is the speed of sound in the material
L_min is the shortest element edge length
T_step is the largest permitted step time

For models with more than one material, the interface uses the smallest element edge length together with the largest value of K found for all materials.