The Eigenfrequency, Prestressed (
) and
Frequency Domain, Prestressed (
) study types (available under
Preset Studies) perform a stationary analysis of the problem to compute the prestressed state and then perform the appropriate prestressed analysis. In both cases, the prestressed state can be computed using any stationary problem. You can use the
Frequency Domain, Prestressed, Modal and
Time Dependent, Prestressed, Modal study types (available under
Advanced Studies) to compute the response to harmonic or time-dependent loads fluctuating around a prior static load. The solution is performed using mode superposition.
See also linper for information about the
linper operator for indicating load terms that should be used by stationary solvers for harmonic linear perturbation. If your license include the Structural Mechanics Module, then also see
Harmonic Perturbation in the
Structural Mechanics Module User’s Guide.
The Eigenfrequency Prestressed (
) study is used to compute eigenfrequencies and eigenmodes that are influenced by a prior static load.
The study consists of two study steps: a Stationary study step followed by an
Eigenfrequency study step. The study computes the eigenfrequencies and the shapes of the eigenmodes when influenced by a prior static load on the structure.
The Frequency Domain, Prestressed (
) study is used to compute the response to harmonic loads fluctuating around a prior static load.
The effects of the preload can be computed with or without taking geometric nonlinearity into account. For this study type it is necessary to specify the magnitude of the harmonic load, as this determines the magnitude of the system response. In order to do this, a Harmonic Perturbation force must be added to the model. For contributing loads (that is, loads that can be added without overwriting the same type of node, such as a boundary load in solid mechanics), right-click the node and select
Harmonic Perturbation. In this case, a load to generate the prestress must be added separately to the model.
The Frequency Domain, Prestressed, Modal (
) study is used to compute the response to harmonic loads fluctuating around a prior static load. The solution is performed using mode superposition.
The effects of the preload can be computed with or without taking geometric nonlinearity into account. For this study type it is necessary to specify the magnitude of the harmonic load, as this determines the magnitude of the system response. In order to do this, a Harmonic Perturbation force must be added to the model. For contributing loads (that is, loads that can be added without overwriting the same type of node, such as a boundary load in solid mechanics), right-click the node and select
Harmonic Perturbation. In this case, a load to generate the prestress must be added separately to the model.
The Time Dependent, Prestressed, Modal (
) study is used to compute the response to time-dependent loads fluctuating around a prior static load. The solution is performed using mode superposition.
