Strain-rate effect on initial crush stress of irregular honeycomb under dynamic loading and its deformation mechanism
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The seemingly contradictory understandings of the initial crush stress of cellular materials under dynamic loadings exist in the literature, and a comprehensive analysis of this issue is carried out with using direct information of local stress and strain. Local stress/strain calculation methods are applied to determine the initial crush stresses and the strain rates at initial crush from a cell-based finite element model of irregular honeycomb under dynamic loadings. The initial crush stress under constant-velocity compression is identical to the quasi-static one, but less than the one under direct impact, i.e. the initial crush stresses under different dynamic loadings could be very different even though there is no strain-rate effect of matrix material. A power-law relation between the initial crush stress and the strain rate is explored to describe the strain-rate effect on the initial crush stress of irregular honeycomb when the local strain rate exceeds a critical value, below which there is no strain-rate effect of irregular honeycomb. Deformation mechanisms of the initial crush behavior under dynamic loadings are also explored. The deformation modes of the initial crush region in the front of plastic compaction wave are different under different dynamic loadings.
KeywordsCellular material Constant-velocity compression Direct impact Cross-sectional stress Initial crush stress Strain rate effect
This work was supported by the National Natural Science Foundation of China (Grants 11372308, 11372307) and the Fundamental Research Funds for the Central Universities (Grant WK2480000001).
- 37.Yu, J.L., Wang, P., Liao, S.F., et al.: Local strain and stress calculation methods of irregular honeycombs under dynamic compression. In: Proceedings of the ASME 35th International Conference on Ocean, Offshore and Arctic Engineering, Busan, June 19–24 (2016)Google Scholar