Finite element-based force identification of sliding support systems: Part Ⅱ-Numerical investigation

摘要

To validate the design process and ensure the safety of an important structure with sliding supports, a finite element-based force identification technique and a strain measurement point selection procedure have been presented in part Ⅰ of this paper. The feasibility and accuracy of the proposed force identification technique and measurement point selection procedure are now verified in part Ⅱ of this paper through numerical investigations on a steel plate support structure. The relationship between the orthogonal property of the selected measurement points and the condition number of the identification equation and the effectiveness of the sequential orthogonal searching algorithm are examined through Monte Carlo simulation. Two cases on force identification of the steel plate structure are then presented: one case concerns concentrated sliding force acting either at node or inside grid, and the other case pertains uniformly distributed sliding load covering a fixed area. For both cases, the strain measurement points of fairly good orthogonal property are firstly determined using the proposed measurement point selection procedure. The positions and magnitudes of initial and final forces are then identified using the proposed force identification technique with or without measurement noise included. The identification results obtained from both cases show that the proposed force identification method can effectively locate and identify the concentrated sliding force and the uniformly distributed sliding load covering a fixed area with no information required on the initial position and magnitude of the sliding force. It is also illustrated that the increase of the number of measurement points can improve the accuracy of identification results.