Research Of The Sub-structural Pseudo-Dynamic Testing Method At Elastic-plastic Phase

Sub-structural pseudo-dynamic method is widely used in seismic testing, this method plans to divide the structure into several parts, so that the huge experiment can be instead by some small ones. As the important part of the structure make the pseudo-dynamic test, and the others make a numerical simulation, and then combine two parts to calculate the structural dynamic response. The method tries to find the best balance between controlling the testing budget and improving the testing efficiency.As a computer-actuator on-line testing, the integration method is important for the pseudo-dynamic test. The actuator’s orders all depend on the integration procedure of the computer at each testing step. In some case the integration method even attribute of the test success or failure. By analyzing various integration methods, and combine with the characteristic of the pseudo-dynamic test, the PCM-Newmark method was chosen as the mainly integration method for the research.The sub-structural pseudo-dynamic test as a hybrid simulation method, the numerical simulation is important part in addition to the testing. The thesis is focus on the structural dynamic performance at phase of elastic-plasticity, so it’s reference the knowledge of the time-history for the numerical simulation. Based on the different performance of the materials, it provides different restoring force model by controlling the parameters, so that achieve the numerical structural stiff matrix and its restoring force at each step. As the thesis mainly researching the pseudo-dynamic test method, it just makes the layer model simulation.As for the structural restoring force performance, it research mainly use the poly-line model. The poly-line model has obvious characteristic is that it contain artificial inflection point. If ignore the inflection processing during the testing, it would achieve less accuracy results. The thesis proposes a inflection processing method and its process flowchart, then research the inflection process influences for the various indicators of the dynamic analysis.When the testing sub-structure goes into elastic-plastic phase, the PCM-Newmark method would be limited. Because this integration method set up at the basis of using the initial structural stiff matrix, while the structure goes into the elastic-plastic phase with hardening effect, it would bring more errors. In this case, FOM method which based on the BFGS quasi-Newton method is proposed, the FOM is applied to improve the integration that use for nonlinear pseudo-dynamic test and get better results. Finally it uses the improvement method for a10layers frame structure seismic analysis that impact under the Hanshin seismic wave (400gal). Then contrast the result with PCM-Newmark method,to get result which shows the FOM improvement is suitable and efficiency.