Papers by Keyword: Dynamic Failure

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Authors: Jin Sung Kim, Hoon Huh, Won Mog Choi, Tae Soo Kwon
Abstract: This paper demonstrates the jig set for the crash test and the crash test results of the tension bolts with respect to an applied pre-tension. The tension and shear bolts are adopted at Light Collision Safety Devices as a mechanical fuse when tension bolts reach designed failure load. The kinetic energy due to the crash is absorbed by secondary energy absorbing devices after the fracture of tension bolts. One tension bolt was designed to be failed at the load of 375 kN. The jig set was designed to convert a compressive loading to a tensile loading and installed at the high speed crash tester. The strain gauges were attached at the parallel section of the tension bolts to measure the level of the pre-tension acting on the tension bolts. Crash tests were performed with a barrier whose mass was 250 kg and initial speed of the barrier was 9.5 m/sec. The result includes the load response of the tension bolts during both the crash tests and finite element analysis.
Authors: Jing Xi Chen, Guang Zhang, Hai Li Tan, Zhen Dong Du
Abstract: Dynamic failure of brittle materials is a rather complex issue. In this paper, experimental work was carried out for plaster model, to study the crack development features of brittle materials under the action of explosion. It shows that couple medium has great influences on detonation wave type. The water has the cushioning effect on detonation wave, which makes the wave crest truncated and results in low wave amplitude and large wave width. Detonation wave type has apparent influence on failure features of brittle materials, of which larger wave width would keep the wall of exploded hole intact and increase the development length of cracks. The research results would be applied to coal mining to increase the efficiency of gas pumping drainage.
Authors: Maria Berkes Maros, Nikoletta Kaulics Helmeczi, Ján Dusza
Abstract: Si3N4 is widely used as a structural ceramic, therefore mechanical characterization, especially in dynamic loading conditions is important task. In the framework of a comprehensive research work aiming at characterizing the dynamic failure process of Si3N4 based ceramics we executed instrumented impact tests. Beside determining various mechanical characteristics we executed failure analysis by fractography, as well. The current paper focuses on the fractographic analysis of the dynamic failure processes of the investigated Si3N4 based ceramics. A detailed morphological analysis has been carried out determining qualitative and quantitative features using macro- and micro-fractography.
Authors: Jian Kang Chen, Zhu Ping Huang, Shu Lin Bai
Abstract: Statistical evolution of microvoids in a particle-filled polymer under plate impact is theoretically studied. Based on the constitutive equations of the material recently obtained by the authors, the velocity of the propagation of one-dimensional strain wave caused by the plate impact is analyzed, and the evolution of the microdamage is calculated. It is shown that the microvoid evolution is influenced by several factors, such as particle size-dispersity, average radius of particles, and the adhesive energy of the interface. The numerical results show that there is a sensitive crest of the impact velocity for microvoid evolution. If the impact velocity reaches the critical value corresponding to the peak value of the crest, the microvoids accumulation will increase rapidly, and it may lead to the dynamic failure of the material.
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