Multiscale Simulation Of Fracture Behavior On Mechanical Micro-components

The demands of microstructure are increasing with the rapid development ofnanotechnology, which requirement high levels of performance. The mechanicalproperties of microstructure， such as fracture， shows very different fromconventional components because of surface effect and small-scale effect.Therefore, it is a key task to expedite discovery of the theory system ofmanufacturing and design for microstructure in the manufacturing industry field.In this paper, QC method was used to research the fracture features of micro-component under different load style, This study has both theoretical andpractical importance for understanding of mechanical property of microstructure.The main work of this paper are:Firstly, It’s built up QC simulation platform, established multi-scale simula-tion model of the stretching process and also verified the validity of the model.Secondly, the size effect and failure mechanism of cantilever were simulatedand analyzed. The effects of thickness, cross-thickness ratio and crystal orienta-tion on elastic modulus were researched. The micro-deformation mechanisms ofthree models with different crystal orientation were also studied. It’s found thatcontinuum theory and its derivative theory are no longer applicable to micro-components. Thickness of the cantilever has great influence on the mechanicalproperties. The elastic modulus of fixed-fixed beam increasing with strain, andthe smaller the beam size is the faster it increases. Size effect and surface effecthave little influence on initial elastic modulus. The initial elastic modulus,maximum deflection and bending strength decrease when thickness of the beamincreases.Finally, the simulation models for compress process of single crystal Cunano-rods were set up. The effects of height and length on the compress processmechanical properties of the nano-rods were analyzed and the transformation andcrack of compress has been studied. Besides, the multiscale simulation has alsobeen developed to study the influences of crystal orientation. The results revealthat the compressing behavior of nano-rods shows remarkable size effect. Thesize effect in compressing has less influence on Poisson’s ratio. While thegeometric dimension occur only in single direction, the mechanics property ofmicrostructure changes slightly.