Experimental Analysis And Theoretical Study Of The Pro-folded Tube

Metal thin-walled structure is a very important object in the field of impact absorbing energy study, which has the advantage of high strength weight ratio, low-cost, high-energy absorption efficiency and simple machining etc. Plenty of research results show that the energy absorption effect of metal thin-walled structure associated with its deformation mode, which mainly determined by it geometric configurations, this paper based on study a new type folding line tube’s energy absorption property under low-velocity impact by changing its geometric configurations to improve its failure mode, this kind of folding line tube’s design concept is introducing prefabricated angle on tube wall, by introduction of this angle,on the one hand, can reduce the initial load, on the other hand can increase the effective plastic deformation area, to enhance energy absorption efficiency. This paper studies energy absorption principle of the folding line tube on the basis of the theoretical, numerical and experimental methods. It is mainly divided into the following several parts:1. Introduce geometry model of folding line tube. Numerical analysis based on the finite element software ABAQUS/EXPLICIT verifies the folding line can guide expected large deformation mode under the action of impact load at low speed, such mode has lower peak load and higher average load compared with symmetric deformation mode of ordinary square tube. Load-displacement curve and deformation mode obtained by low speed drop hammer experiment are similar to the finite element simulation results’, which can verify the reliability of the numerical results and efficient energy absorption characteristics of folding lines square tube. Details see chapter2.2. Based on the theory of super folding element,energy absorption formula on folding line tube under the action of the quasi static with different standard segment and different folding line tube size is deduced, and quantitative relationship between the energy absorption performance indicator and geometry configuration parameters is established. Details see chapter3.3. With cowper-symonds constitutive relation and actual deformation in the experiment of the folding lines tube as foundation, considered dynamic effects, to revised formula of strain rate deduced by wierzbicki for the super folding unit, energy absorption formula on folding line tube under the action of impact load with different standard segment and different folding line tube size is deduced. In addition, based on theory and the results of numerical comparison, to modify the formula of folding line pipe under low-speed impact, which result fit better with numerical results, also very close to compare the experimental results, error under the condition of quasi static of the theoretical results and experimental results is1.6%, error under the theoretical results with the experimental results of impact load conditions is6.6%.Details see chapter4.