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Deng G.-Q.,No4 Engineering Research Institute | Jin Q.-K.,Beijing Institute of Technology | Yang X.-M.,No4 Engineering Research Institute
Binggong Xuebao/Acta Armamentarii | Year: 2012

The damage characteristics of rock were brought out by penetrating-exploding test of SAP, and the effect factors were analyzed, which should be taken care in numeric simulation of weapon effect. Based on the hydro plastic-elastic model, a new constitutive model for rock was proposed. The compressing effect can be obtained by the equation of sate, and the damage cumulation can be got by JHR-TCK equations, thus all the factors of penetration and explosion effect of SAP are taken into account. At last, the test results and simulation data were compared.

Deng G.-Q.,No4 Engineering Research Institute | Yang X.-M.,No4 Engineering Research Institute
Baozha Yu Chongji/Explosion and Shock Waves | Year: 2014

This numerical simulation study was undertaken to investigate the penetration and explosion efficiency of a sequence of precision-guided earth penetrating weapon (EPW) into hard rock target. The main objective of the study was to ascertain the damage depth of using much more EPW, the relative depth would decreases with bomb number decreasing, the ultimate depth was limited. The simulations were performed using EP3D-a 3D explosion and penetration efficiency hydrocode. To describe the engineering rock body on the test site, it was divided into two parts, which were structure body and structure interface. A new rock constitutive model was built up for homogeneous structure body, and moreover, a space block model was brought out, which takes into account the non-homogeneousness of nature rock based on structure interface. Through this model, lots of numerical simulation works were done on repeat attack effect, and the numerical results agreed well with those of experiments, all of them made it clear that the ultimate damage depth of repeated attack was a limited value because of residual fragment, impact deviance and non-homogeneousness of nature rock.

Deng G.,No4 Engineering Research Institute | Yang X.,No4 Engineering Research Institute
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2014

To investigate the characteristics of rock specimen under static cyclic loading and repeated dynamic impact, comparative tests are carried out on rock rigid test machine and SHPB device respectively, and the stress-strain relationships are also obtained respectively. It is very difficult to obtain the relationships of rock under repeated impact. Compare the relationships of specimen under two types of loading, except strain ratio effect, there are so many similar characteristics between them. Firstly, the damage process is progressive, which includes yield, crack and broken steps. Secondly the stress-strain relation profile can be classified as elastic, harden, soften and residual part. Lastly the bearing capacity and modulus are gradually decreased after maximum point. The comparative experimental investigations illustrate that the rock mechanical properties under repeated dynamic impact can be approximately made out through the results of static cyclic loading.

Deng G.-Q.,No4 Engineering Research Institute | Yang X.-M.,No4 Engineering Research Institute
Binggong Xuebao/Acta Armamentarii | Year: 2013

In SPPB test, the strain-stress relationship of rock specimen is indirectly gained from the strain waveforms on incident bar and transmission bar. The nonlinear effect of the actual bar impact is ignored, moreover, some assumptions must be satisfied, so the true material performances may be hided. In traditional SHPB test, the specimen is destroyed when an impact force is loaded, and the load amplitude is large so that these effects are relatively small. While in the repetitive SHPB test, the load amplitude is relatively small and the change of waveform is gentle so that it is difficult to accurately determine the starting points of incident wave, transmitted wave and reflected wave. The difference of the starting points leads to very different stress-strain curve, which will bring great difficulty to distinguish the real stress-strain relationship curves. A paper waveform shaper is used to produce "bell" wave, eliminating high frequency oscillation influence of "square" wave. The comparative data shows that the selection of reference point of waveform exercise a great influence on the calculated results. And the difference of calculated waves is obtained by two-wave method and three-wave method. Finally, the numerical simulation method is used for the numerical simulation of the elastic and ideal elastic-plastic material models. The analysis results show the difference between indirect stress-strain relationship of SHPB test and true relationship can be obtained from the calculated results.

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