Transient response analysis

A transient response analysis calculates the effect of time-dependent load sources that act in any regular or arbitrary manner on a structure. Typical transient load sources include wind gusts, seismic events, vibrating machines, blast loads, pulse loads, footfall excitation, moving traffic, etc.



Important points

  1. A transient response analysis is linear only and therefore cannot be performed if your model contains cable elements.

  2. Because it is linear, a transient response analysis treats tension-only and compression-only members as normal members that can take tension or compression.

  3. P-D and P-d effects are not taken into account during a transient response analysis.

  4. A buckling analysis cannot be performed with transient load cases and therefore compression effective lengths from a buckling analysis are not available when doing a steel member design/check on transient load cases. If you are performing a steel member design/check on combination load cases that contain a mixture of static and transient load cases then the transient load cases will not contribute to the calculation of the compression effective lengths. This may not be correct and so you should consider specifying your compression effective lengths manually in those cases.

  5. A transient response analysis requires a dynamic frequency analysis to be conducted first.

  6. The transient response analysis must be repeated after a dynamic frequency analysis because its results will have been deleted.

  7. The accuracy of the transient response analysis depends on the accuracy of the dynamic frequency analysis on which it is based. It is therefore important that you set up your model correctly to achieve accurate dynamic frequency analysis results. For example, if master-slave constraints are used then positioning of the master nodes is particularly important for correct mass distribution. For more information, refer to "Dynamic frequency analysis".


For a full step-by-step guide on how to prepare for and perform a transient analysis, refer to "Step by step guide to transient response analysis".