APPLICATION OF DIGITAL IMAGE ANALYSIS FOR SIMULATION OF MICRO-MECHANICAL RESPONSE OF MICROSTRUCTURES OF COMPLEX GEOMETRY

摘要

Microstructures of engineering alloys often contain non-uniformly distributed features of complex geometry present at widely different length scales. Attributes of microstructural geometry have dominant influence on the mechanical behavior of materials. Therefore, it is of interest to incorporate detailed quantitative description of the geometry of microstructures in micro-mechanical analysis of materials. In this contribution, a digital image analysis based methodology is presented for performing finite elements (FE) based simulations on the microstructural digital images, and for linking the interactions among microstructural features at different length scales. The practical application of the method is demonstrated via FE-analysis on the microstructure of a cast Al-alloy, where the length scales of micro-pores and silicon particles differ by two orders of magnitude. The simulation captures the effect of non-uniformly distributed micro-pores at length scales of 200 to 500 microns on the local stresses and strains around silicon particles that are at the length scales of 3 to 5 microns. Three-dimensional FE-based computations are presented for simulation of the growth of non-uniformly distributed micro-pores of complex geometry under applied tensile load, and finally an application of microstructure modeling to incorporate detailed microstructural information in FE-simulations is discussed.