Elimination of spurious higher‐mode response in pseudodynamic tests

Abstract

Abstract In a pseudodynamic test, errors in restoring‐force feedback are introduced into numerical computations. Some of these errors can excite the higher‐frequency response of the specimen. In this paper, the use of viscous and numerical dampings to eliminate spurious higher‐frequency effects is studied. Since the tangent stiffness of a non‐linear specimen cannot be measured accurately, initial‐stiffness‐dependent viscous damping is considered. In addition, an explicit integration algorithm with desired numerical damping properties is proposed and examined. The analytical and numerical studies presented indicate that viscous‐damping properties can be substantially changed by non‐linear deformations. For this reason, the use of numerical damping appears to be more advantageous.