Metal Thin Walled Tube Structure Drop Experiment And Simulation

The bending and bucking strength of the Metal thin walled tube are much higher thansolid roads with the same cross section, so the Metal thin walled tube can effectively absorbthe impact energy. And this kind of structure is widely used in aerospace, nuclear industry,chemical industry, automobile industry and military industry. However, due to the thin wallof these compents, some local concave is easily happened under impact load, which greatlyreduces the overall carrying capacity and buckling strength. Through the research of thethin-walled cylinder under the impact load, we can find the weak unit of the structure andprovide an effective basis for the further structural optimization and design.The experimental system was established on the base of the swing arm type machine,strain gauge, bridge and acoustic control trigger system, to study the droppingcharacteristics. Through passing the strain gauge on the surface of the thin walled tubestructure, we tested the strain rule under different conditions (empty inside and filling sand)and different dropping parameters (drop height).In order to obtain the continuous results in the process of dropping as many as possible,this article does a further study of the strain rule on the surface of the thin walled tube byusing the finite element analusis software ANSYS/LS-DYNA. This article studied the ruleof shocking response under different dropping conditions (drop height, drop angle andthickness of the wall). Furthermore, this article also studied the rule of the shockingparameters (impact stress, accelation and impact force) corresponding to droppingparameters, finding that it is feasible to decrease the dropping impact strength to thestructure by changing the dropping angle or increasing the thickness of the wall. Throughthe comparison of the simulation results of the structure empty inside and filling sand, itfinds that the rule of the shock response is almost coincident. However, when the modalwas filled with medium, the parameter value of the impact stress, strain and the accelationhas dramaticlly increased. In the end, through the comparison of the accelation value of thesimulation and experiment, verifying the correctness of the simulation.Through the study of the modal analysis of thin-walled cylinder, each order naturalfrequency is obtained. We can avoid using this kind of structure under its natural frequenciy,and we can reduce the damage of the structure by avoiding the resonance phenomenon.