Titulo:Some Fundamental Issues in Discrete Element Modelling of Particle Systems
Conferenciante Prof. Y.T. Feng
Area Tematica:Computational material failure and fracture
Fecha, lugar y evento:26/10/2011, Barcelona, II International Conference on particle-based Methods Fundamentals and Applications PARTICLES 2011
The Discrete Element Method has now firmly established as a powerful predictive tool for the numerical modelling of many problems involving discrete and discontinuous phenomena. To model any practical particle system, larger sized discrete elements than the actual particles have to be employed in the discrete element model in order to reduce the problem scale to a computationally manageable level for currently available computer resources. Also, multiscale-sized particles are often present in many industrial applications and these cannot be represented at the correct physical scale in models. There are two fundamental issues associated with the use of artificially enlarged discrete elements: 1) Under what conditions will this upscaled discrete element model represent the original physical problem? 2) What is the solution accuracy of the model in terms of the number of discrete elements used? These two issues have important implications that are still not well understood. The first issue is preliminarily addressed in our previous work . Based on the introduction of particle strain and stress, the work establishes three similarity principles, namely geometric, mechanical and dynamic, under which the scaled model can exactly reproduce the mechanical behaviour of a physical model. In particular, the concept of the scale invariance interaction law is further introduced and the scalability of a number of most commonly used interaction laws in the discrete element modelling is examined. In the current work, the dynamic similarity principle is further refined. Also a preliminary attempt is made to investigate the solution accuracy of a discrete element model in terms of the number of elements used when the geometric similarity conditions are not met.