Experimental Study On Flexible Body Impact Problem

In this paper,an in-plane direct impact experiment between a rod and a circular plates is designed,which applied the high-speed camera system to the filed low-speed collisions.The high-speed camera system could measures the velocity and strain of whole pattern instead of a single point,and reveals the propagating processes of strain wave during the contact process,breaking the limitations that the existing measurement methods have in the impact experiment field.In this experimental,an experimental platform is designed to be used for the rod-plane impact experiment and the measuring instruments that are needed.Three methods are used to measure the response of the impact,Laser-Doppler-Vibrometer(LDV),strain gauge,and high-speed camera system respectively.In this paper,the influence of the quality of speckle and calculation parameters on the experiment results of high-speed camera is studied,an appropriate reference range is provided.The results shows that during the contact period,the response measured by the high-speed camera system agrees well with that measured by the strain gauge and LDV,which demonstrates the applicability of the high-speed camera in the research of low-speed impact.However,It is found that after the contact period,compared to the results measured by the strain gauge and LDV,there are some obvious wave errors in the strain and velocity results measured by the two-dimensional high-speed camera.After some analysis in the frequency and amplitude of the wave,it can be proved that the error was caused by the out-plane displacements,owning to the vibration of plate.In this paper,the method of eliminate errors are discussed.