A void coalescence-based spall model is presented using stress relaxation equations based on the assumption that the main effect of the microcracks is to reduce the area over which the stress acts in the early stages and the stress decreases to porosity-dependent value in the void coalescence stages
Crack straining-based spall model
β Scribed by Danian Chen; S.T.S. Al-Hassani; M. Sarumi; Xiaogang Jin
- Book ID
- 104344023
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 746 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0734-743X
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β¦ Synopsis
Mean void growth-based spa11 models that avoid the complications of nucleation have been successfully applied to the problem of ductile spallation. However, similar models based on mean crack growth, applicable to brittle spallation, are not promising. This is because it remains to be demonstrated how an appropriate mean crack size is chosen to identify the brittle spa11 strength as the threshold pressure for crack growth. In the authors' view, the solidity evolution is not merely a consequence of the nucleation and growth of cracks but also determined by the crack straining caused by the relaxed tensile pressure. This paper presents a crack straining-based spa11 model which assumes that the inelastic volumetric strain caused by the relaxed tensile pressure at a critical fragment volume is the main factor governing the solidity evolution during the process of coalescence and fragmentation. Such an approach makes the modelling of brittle spa11 compatible with that of ductile. The developed model requires only two additional parameters to those required by the chosen constitutive model and equation of state. We present the comparisons between experimental and computational simulation of the free surface velocity history of the target in a plane impact plate experiment. These show very good agreement.
π SIMILAR VOLUMES
The original Cochran-Banner spall model was modified to suit the usual definition of damage and to abandon the simplifying approximation as unnecessary. The strength function given by Cochran-Banner was maintained using the redefined damage and the correction concerning the volume of the mesh cells