Using finite element simulation, we investigated the spalling of such brittle materials as concrete and rock, studied the attenuation mechanism governing the stress wave propagation through the specimen of brittle materials, and found two kinds of mechanisms: the small amplitude linear attenuation of the elastic wave due to the geometric dispersion of the large size specimen, and the exponential decay of the viscoplastic wave associated with the strain rate due to the constitutive relation. Based on this, we proposed a peak fitting formula of exponential type stress wave with a constant term. It is suggested that we should choose a slender specimen in the spalling test in which the attenuation of the stress wave can be ignored. In addition, we studied the spalling damage of concrete and rock. The scab thickness obtained from the finite element method agrees well with one-dimensional stress wave theory, verifying that the method for determining the spalling strength by one-dimensional stress wave theory is effective. By comparing the scab shape and the tensile stress wave of the brittle material loading by three kinds of the incident wave, we proved that it is more feasible to obtain a flatter spalling cross-section and more precise strength by using an asymmetric incident wave.
Rinehart J S. Some quantitative data bearing on the scabbing of metals under explosive attack[J]. Journal of Applied Physics, 1951, 22(5):555-560. doi: 10.1063/1.1700005
[3]
Klepaczko J R, Brara A. An experimental method for dynamic tensile testing of concrete by spalling[J]. International Journal of Impact Engineering, 2001, 25(4):387-409. doi: 10.1016/S0734-743X(00)00050-6
[4]
Díaz-Rubio F G, Pérez J R, Gálvez V S. The spalling of long bars as a reliable method of measuring the dynamic tensile strength of ceramics[J]. International Journal of Impact Engineering, 2002, 27(2):161-177. doi: 10.1016/S0734-743X(01)00039-2
Hu Shisheng, Zhang Lei, Wu Haijun, et al. Experimental study on spalling strength of concrete[J]. Engineering Mechanics, 2004, 21(4):128-132. doi: 10.3969/j.issn.1000-4750.2004.04.023
[6]
Zhu J, Sun C, Qian Z, et al. The spalling strength of ultra-fiber reinforced cement mortar[J]. Engineering Failure Analysis, 2011, 18(7):1808-1817. doi: 10.1016/j.engfailanal.2011.05.001
Chen Baisheng, Xiao Yan, Huang Zhengyu, et al. Experimental study on the spalling strength of fiber reactive powder concrete[J]. Journal of Hunan University(Natural Sciences), 2009, 36(7):12-16. http://d.old.wanfangdata.com.cn/Periodical/hndxxb200907003
[9]
Holmquist T J, Johnson G R, Cook W H. A computational constitutive model for concrete subjected to large strains high strain rates, and high pressure[C]// Jackson N, Dickert S. The 14th International Symposium on Ballistics. USA: American Defense Prepareness Association, 1993: 591-600.
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