Improvement On Common Plane Detection Algorithm And Three-Dimensional Discrete Particles Generation Algorithm

Discrete particles are commonly used in civil engineering,hydraulic engineering,traffic engineering,storage,mining and so on.Simulation analysis of discrete particles is based on contact detection between particles.It is the very important to judge the contact types and contact positions quickly and correctly,because contact detection is a key step of discrete particles' numerical simulation.Many researchers have been studying on contact detection, and many methods have been suggested.One of the most popularly methods is the Common Plane(CP),because it is simple in its physical sense.The main obstacles for CP detection are the accuracy and the efficiency.Nezami et.al suggested the Fast Common Plane method in 2004.While this method is only valid for separated blocks in his paper.When it comes to other blocks,it takes measures to separate the blocks temporarily according to the CP from the previous time step.And the blocks are moved back after the CP's determination.But for some materials,such as jointed rock,the separation process will possibly bring mistakes in.In this paper,it is proved that it is not necessary to separate blocks temporarily,and the algorithm is valid for all blocks in CP detection.Particle generation is the basis of simulating discontinuous media with DDA.The current methods have the compressing or falling calculation added into the particle generation process,and this makes the process to be time-consuming.How to generate a given particles system fast is the key point to judge a particles generation algorithm.As mentioned above,the common plane detection algorithm for polyhedron blocks and the 3D particles generation algorithm are studied in this paper.The work and research results are summarized as follows:1.Based on the Fast Common Plane(FCP) method suggested by Nezami for separate blocks,the FCP method is proved to be useful for any two polyhedron blocks.2.Based on the 2D Advancing Front Segment method suggested by Feng et.al,the Advancing Front Face method is presented in detail.And a few measures are adapted to get a more efficient and denser ball particles configuration.3.On the basis of the ball particles configuration,the polyhedron particles generation algorithm is suggested.