# Time Integration Scheme¶

Time integration schemes are used to calculate the system equations dependent on time. Generally you can differ between explicit and implicit procedures. Explicit time integration schemes only use information from time steps aleady known for calculating the next time step and hence lead to explicitly solvable equation systems. Yet the stability of the procedure depends on the system’s stiffness and the chosen time step intervals. Therefore, if uncertain, it is convenient to choose an implicit algorithm.

Hint

For the CalculiX solver the implicit time integration is done via the HHT time integration scheme, where the parameter $$\alpha$$ which determines the degree of numeric damping of the system is chosen to -0.05.