SOLVERS Home: Solution Type

Description

Specifies which of the two solution techniques is used to calculate the transient response in the Linear Transient Dynamic solver.

Full System

If set, the direct integration method is used.

The global stiffness, mass and damping matrices are used in the step-by-step integration procedure. The matrices are formed at the start of the solution, and then updated whenever the time step increment changes.

Mode Superposition

If set, the mode superposition method is used.

The response is calculated by combining the response of modes calculated by the Natural Frequency solver. One of the advantages of the superposition method is that it is considerably faster than the full system method, once the modes have been calculated. Mode superposition is also useful in situations where we wish to exclude high order modes that are not significant to the response of interest, or when we wish to include modal damping. For very high frequency response analysis, the mode superposition method may not be appropriate, as too many modes may be required to adequately capture the structure's response. In that case, it is more efficient to use the full system method with a time step and mesh size appropriate for the analysis.