A New Iterative Hybrid Test Method With Force Correction

The real-time hybrid test method is an effective seismic test method for civil engineering structures.The method has good flexibility,economy and accuracy by dividing subnumerical substructure and physical substructure,and performing real-time synchronous calculation and loading.With the development of high-performance computer and high-precision loading equipment,real-time hybrid test has been widely used in different fields.In this paper,the real-time hybrid test method is firstly applied to the experimental research of high-speed train shock absorber,which provides a new idea for the experimental research of high-speed train;in order to solve the problem of large calculation delay in the real-time hybrid test in complex structure,a new iterative hybrid test method based on force correction is proposed,which is verified by numerical simulation and physical test under various working conditions The effectiveness of the proposed method is also discussed.The main research contents and conclusions are as follows:(1)Real-time hybrid tests of high-speed train anti hunting damper are carried out to find out the influence law of time delay on high-frequency response specimen.The compensation effect of time delay compensation method based on constant speed assumption and adaptive time delay compensation method in high-frequency response real-time hybrid test is compared and analyzed,and the critical speed of high-speed train under different wheel diameter difference and track irregularity is given.The results show that: when the physical substructure is a viscous damper,the time delay will enlarge the displacement amplitude and frequency of the physical substructure under high frequency response;the effect of adaptive time delay compensation is better than that of constant speed assumption;the critical speed of high-speed train decreases with the increase of track irregularity and wheel diameter difference.(2)A new iterative hybrid test method based on force correction is proposed,and the force correction strategies of equivalent linear model and equivalent Maxwell model are given.The proposed method avoids the time delay by iteration,and improves the iterative convergence speed and loading stability by force correction.The proposed method is verified by numerical simulation of single-layer frame with shock absorber under various working conditions.The results show that: compared with the direct iterative hybrid test method,the proposed force modified iterative hybrid test method optimizes the solving process of the motion equation of the iterative hybrid test,improves the solving accuracy of the motion equation,and has better convergence speed and loading stability.(3)Taking the three-story frame with viscous dampers on the first floor as an example,the numerical simulation and physical test of the iterative force correction test of equivalent linear model and equivalent Maxwell model are carried out respectively,and the force correction ability of the two force correction strategies is compared and analyzed.The results show that the convergence speed and accuracy of the displacement response of the physical substructure are high,and the force correction effect of the equivalent linear model is better than that of the equivalent Maxwell model.The new iterative hybrid test method with force correction can avoid the problems of time delay and the stability of integral algorithm,and has good convergence,which expands the idea and application scope of hybrid test.