13th International Conference on Fracture June 16–21, 2013, Beijing, China -1- Equivalent dynamic mechanical properties of grid cylindrical structure Lin Xiao-hu1,*, Gao Xuan1, Yang Er-meng1, Xing Chun-lei2 1 Army Aviation Institute of PLA, Beijing 101123, China 2 Department of Engineering Mechanics, Beijing University of Technology, Beijing 100124, China * Corresponding author: mmlinxiaohu@126.com Abstract Grid cylindrical structure with infinite variety of cell shape and arrangement receives much concern, which results in many applications of these structural materials in aerospace and aviation engineering. However, the complexity of structure will bring high time-consuming in calculation and unanticipated self-contract in researching dynamic performance. Equations were used to get the equivalent material properties by theoretical derivation. Then dynamic mechanical properties of both equivalent structure and grid cylindrical structure were investigated. In detail, the dynamic deformation and energy absorption characteristics of the structure under different lateral impact velocities were analyzed by software LS-DYNA. The relative density and the relative thickness of the grid cylindrical structure to equivalent performance effect were taken into account. The results show that when relative density and relative thickness are defined in certain range, the equivalent method has high accuracy. This equivalent method provides a reference for the impact properties of complex grid cylindrical structure with arrangement periodically. Keywords Grid structure, Homogenization, Deformation mode, Energy absorption, Effective property 1. Introduction Grid structure has been widely used in aerospace, automotive industry, civil materials, biological engineering, transportation and other applications because of excellent energy absorption, high load carrying capacity, high specific strength, high specific stiffness and low structural weight [1,2]. It not only contains mesoscopic mechanics characteristics, but also has whole macro performance. These characteristics make the anti impact properties of structure greatly improved. In addition, the designability of cell geometric topological provides a broad platform for the development of grid structure. Therefore, the scientists and mechanical experts pay great attention to study grid structure in order to acquire better integrated design. At present, impact resistance performance, energy absorption capability and dynamic mechanical properties of grid structure have been studied by many scholars. For example, The elastic response of triangular, hexagonal and quadrilateral grid structure has been obtained in by Hohe et al.[3,4].The deformation mode and load carrying capacity of hexagonal grid structure were studied by the numerical simulation in by Ruan et al. [5,6] and Zou et al.[7].The formulas of bearing capacity and energy absorption ability were deduced through the deformation model of hexagonal grid structure in the high speed impact, and the energy distribution was discussed in Hu et al.[8]. Researched in Hong[9] and Zarei et al.[10] is the impact direction angle on in-plane dynamics performance. The mechanical properties of grid structure filled with circle cells were researched through experiment and numerical simulation in Papka et al.[11,12].Nevertheless, all of the above researchers adopt discrete element method to solve the problem of the periodic grid structure, which not only costs a lot of computation resources, but also is infeasible sometimes [13]. In order to simplify performance research of grid structure, the equivalent elastic constants have been explored over the last few years. Gibson and Ashby [14] have investigated the equivalent elastic
RkJQdWJsaXNoZXIy MjM0NDE=