Study On 3D Discrete Element Method And Its Application In The Impact Fracture Behavior Of Automobile Laminated Glass

Automobile laminated glass, which is pressed from two pieces of glass plate and onepiece of polyvinyl butyral (PVB) film under high temperature, is one of important parts ofautomobile. It is shown that the mechanical property, especially the shock resistance of au-tomobile laminated glass is very important for passenger's safety. Since the essence of thedynamic damage and failure processes of laminated glass are the materials transferring fromcontinuum to non-continuum, there are some problems when using traditional numerical pro-ceedings based on the continuum mechanics theory, as well as experimental study. DiscreteElement Method (DEM) is a powerful method proposed to deal with the non-continuum me-chanics problem. In the middle of the last century, Oda and Zang successfully establisheda two-dimensional discrete element model of laminated glass beam. Based on this model, a3D discrete element model of laminated glass plane is present in this thesis.In this thesis, the 3D DEM is used to study the impact fracture phenomena of laminatedglass. Firstly, a 3D discrete element model of laminated glass plane, which contains thegeometric model, the constitutive model and the fracture model of glass material andPVB, is established. A corresponding numerical analysis code, which contains a pre-postprocess system and a core computational program, is developed. Secondly, a new contactdetection algorithm, which is called Improved Zoning Algorithm (IZA), is presented. TheIZA algorithm is developed for the large size ratio discrete element system. The computingefficiency of the algorithm is discussed by using many numerical experiments. Thirdly, thevibration process of a block and a cantilever beam under impact loadings are calculated.Simultaneously, the impact process of a single glass plane and a laminated glass plane arenumerically simulated. Those two examples are calculated by using both our 3D DEMcode and the famous commercial FEM code LS-DYNA in the same condition. From thenumerical analysis, it is obvious that the results of 3D DEM are almost the same as thecorresponding results of LS-DYNA. Fourthly, the impact fracture behavior of a laminatedglass beam is demonstrated; the fracture process on the impact face is surveyed. As a result,the impact fracture process of a single glass plane and a laminated glass plane are simulatedrespectively. The entire failure processes in detail are presented. By comparing the impactforce and reduction of kinetic energy of impact body between those two models, thenumerical method is applied to demonstrate the advantage of laminated glass in passenger'ssafety.