Shock enhancement of cellular materials subjected to intensive pulse loading
Cellular materials can dissipate a large amount of energy due to their considerable stress plateau, which contributes to their extensive applications in structural design for crashworthiness. However, in some experiments with specimens subjected to intense impact loads, transmitted stress enhancement has been observed, leading to severe damage to the objects protected. Transmitted stress through two-dimensional Voronoi cellular materials as a protective device is qualitatively studied in this paper. Dimensionless parameters of material properties and loading parameters are defined to give critical conditions for shock enhancement and clarify the correlation between the deformations and stress enhancement. The effect of relative density on this amplifying phenomenon is investigated as well. In addition, local strain fields are calculated by using the optimal local deformation gradient, which gives a clear presentation of deformations and possible local non-uniformity in the crushing process. This research provides valuable insight into the reliability of cellular materials as protective structures.
KeywordsCellular materials Voronoi model Pulse loading Shock enhancement Local strain field
This work is supported by the National Natural Science Foundation of China (Grant Nos. 11572214, 11402163, 11672199 and 11602161), Shanxi Scholarship Council of China (2013-046), Natural Science Foundation of Shanxi Province (No. 201601D021025), State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body (No. 31615008) and the Top Young Academic Leaders of Shanxi, Opening Foundation for State Key Laboratory for Strength and Vibration of Mechanical Structures and Opening Foundation for State Key Laboratory of Explosion Science and Technology (Grant No. KFJJ16-07M). The financial contributions are gratefully acknowledged.
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