Rho_inf Bathe: Seismic response of single-degree-of-freedom oscillators

The rho_inf Bathe method is a composite time integration method, with adjustable numerical dissipation at the high frequency limit.

The rho_inf method implemented in ADINA 9.6 allows the strength of the numerical dissipation to be adjusted, the standard Bathe method always gives the maximum dissipation. Hence, the selected time step is used to control the cut-off frequency of the solution and the rho_inf parameter is used to control the strength of the dissipation.

Here we investigate the response of 100 SDOF oscillators subjected to the El Centro East West seismogram base motion acceleration. These responses are linear.

In non-linear structural dynamics, the mode superposition method cannot be used and the unconditional stability of methods in linear direct method is violated, so there the time integration must provide accuracy and stability. This will be further investigated in a separate post.