Applications of micro-structural finite element method to dynamic granular mechanics

• Main Authors: Yeou-Cherng Chiang, 姜有成
• Other Authors: Yen-Lin Chung
• Format: Others
• Language: zh-TW
• Published: 1993
• Online Access: http://ndltd.ncl.edu.tw/handle/47989387515112797773

碩士 === 國立臺灣科技大學 === 營建工程技術學系 === 81 === The purpose of this work is to study the dynamic response of granular structures which are regularly packed by particles of equal size, and to study the energy release rate of cracked granular structures subjected to dynamic loads. The contact points of two particles in granular materials are assumed to be jointed together by pseudo springs. These contact stiffness of the the pseudo springs are evaluated by means of Hertz contact throry. In this work, the dynamic micro-structural finite element method(DMFEM), a new numerical model, is developed. this new model is the extension of the micro-structural finite element method(MFEM), proposed by Liao and Chang. The formula of DMFEM is derived based on the finite element technique and Hamiltian principle. By using the finite element technique, the degree-of- freedom of particles inside the structure can be transformed to the nodal degree-of-freedom. By means of Hamiltian principle, the equations of motion for granular structures are derived. The scope of this theis mainly includes three parts. First, under dynamic loads, the behaviors of the granular structures and the effects of the packing of particles are studied. The dynamic response obtained by the idea of discrete body is also compared with that by the concept of continuous body. Second, study the effects of the different granular packing on the dynamic responses of the composite granular structures that are composed of different kinds of granules. Finally, the dynamic energy release rate of cracked granular structures is investigated and it is compared with the static energy release rate of the same size of structures, the same boundary conditions , and the same loads.