Title: Multiscale Simulation Tools for Heterogeneous Materials Speaker: Wing Kam Liu, Director of NSF Summer Institute on Nano Mechanics and Materials, Northwestern University, Department of Mechanical Engineering Date/Time: Tuesday, July 11, 2006, 10:00 – 11:00 am (MST) Location: Building 980, Room 95 (Sandia NM) Building 915/W133 (Sandia CA) Brief Abstract: Nanotechnology, nanomechanics and nanomaterials have an overall potential for the betterment of our society, for example in national defense, homeland security and private industry. These fields can make our manufacturing technologies and infrastructure more sustainable in terms of reduced energy usage and environmental pollution. Material properties are inherently a function of the microscale interactions at each distinct scale of deformation. We are developing the next generation of computer-aided design (CAE) simulation software that integrates nano and micro mechanisms into CAE capabilities for life-cycle analysis and design. The internal power generated within the microstructure is represented via surrogate micro-fields, allowing the discrete microstructure to be replaced by a much more computationally efficient multiscale continuum. This multiscale homogenized continuum representation of the microstructure can be utilized at any scale, from the strength of the bonds between atoms to the macroscale. Multiscale constitutive relations are determined through a computational cell modeling technique which involves spatial and temporal averaging of the microstresses at various scales. Progressively coarser and larger domains can be solved using these preformulated homogenized constitutive relations which represent the deformation mechanisms at each scale. Hence, the deformation and constitutive behavior become more highly resolved as more scales of analysis are included. This facilities a smooth transition between a purely continuum treatment at coarser scales and an atomic scale resolution at finer scales. Hence, the estimation of the overall strength and toughness of the material is performed in terms of the important microstructural features and mechanisms. The theory provides a useful design tool for conventional and novel multi-component material systems in which heterogeneous deformation fields determine the overall.properties.CSRI POC: Jonathan Zimmerman, (505) 294-2437 |