主办单位：西安交通大学航天航空学院
强度与振动教育部重点实验室
报告人: 1、哈佛大学教授J. W. Hutchinson（美国科学院、工程院、艺术与科学院院士、我校荣誉教授）
2、剑桥大学教授John Willis（英国皇家学会院士、我校荣誉教授）
时 间: 2007年8月28日(周二)上午10:00－12:00
地 点: 强度与振动教育部重点实验室会议室（教一楼南208）
报告内容：
1、John W. Hutchinson: Stiff Materials With Zero Thermal Expansion
A family of robust stretch-dominated bimaterial lattices is introduced which combines low (or zero) thermal expansion with high stiffness, structural robustness over wide temperature ranges and manufacturing facility. This combination of properties is unavailable through any other material solution. The concept uses two constituents configured as adjoining sub-lattices. It accommodates the thermal expansion through rotation of the members of one sub-lattice. Moreover, the lattice exhibits large stiffness to weight because it is fully triangulated and does not rely on rotational resistance at the joints for structural rigidity. The stiffness of these lattice materials is shown to be near-optimal. A wide range of constituents can be used to build the new lattices enabling many desirable properties to be incorporated, especially high strength and toughness. Examples of both planar and volumetric lattices are presented, and their thermomechanical properties derived. The results are verified by conducting experiments and finite element simulations on a lattice fabricated using aluminium and titanium alloy constituents.
2、J.R. Willis: Some unconventional phenomena associated with homogenization and the effective response of composite materials
Intense current interest in electromagnetic phenomena such as superlensing and cloaking, and so-called “left-handed materials”, has motivated the search for similar phenomena in elastodynamic wave propagation. An important property of the equations of electrodynamics is that they retain their form under arbitrary transformations of coordinates. The same is not true of the equations of elastodynamics but it is true of a set of more general equations that in fact describes the effective response of composite materials. This general closure property will be demonstrated, and the underlying general theory for effective response will be outlined and illustrated by means of simple one-dimensional examples.
欢迎校内外教师、研究人员和同学参加!
