Analytical exploration of α-function explicit method
pseudodynamic testing of nonlinear systems
Shuenn-Yih Chang (张顺益) and Yu-Chi Sung (宋裕祺)
Department of Civil Engineering, National Taipei
University of Technology, Chinese Taipei 106-08
Abstract: It has been well studied that the
γ-function explicit method can be effective in providing favorable numerical
dissipation for linear elastic systems. However, its performance for nonlinear
systems is unclear due to a lack of analytical evaluation techniques. Thus, a
novel technique is proposed herein to evaluate its efficiency for application to
nonlinear systems by introducing two parameters to describe the stiffness
change. As a result, the numerical properties and error propagation
characteristics of the γ-function explicit method for the pseudodynamic testing
of a nonlinear system are analytically assessed. It is found that the upper
stability limit decreases as the step degree of nonlinearity increases; and it
increases as the current degree of nonlinearity increases. It is also shown that
this integration method provides favorable numerical dissipation not only for
linear elastic systems but also for nonlinear systems. Furthermore, error
propagation analysis reveals that the numerical dissipation can effectively
suppress the severe error propagation of high frequency modes while the low
frequency responses are almost unaffected for both linear elastic and nonlinear
systems.
Keywords: pseudodynamic test; nonlinear error
propagation; numerical dissipation
