Crashworthiness Analysis And Applications Of Lightweight Structures Base On Bionics

Impacts and crashes are very dangerous and threatening to people's lives and properties. Therefore, analyses for structural crashworthiness are of great importance in research. Energy-absorbing devices are structures specifically designed to absorb energy with stability and controllability. Among them thin-walled metal structures are lightweight and are able to dissipate sufficient kinetic energy with irreversible plastic deformation in collision. Materials and configuration of the structures have large contributions to crashworthiness which can be greatly improved through structural optimization.Bionics can be adopted to study the mechanisms of nature whose evolution keeps providing us with rich inspirations on structural design and improvement. A good example is beetles that have delicate and complicated body structures. Their rigid cuticles not only protect the body and organs against impacts from outside by absorbing crash energy, but also are light-weight enough for fly. Those make them excellent material prototypes for device of structural crashworthy and energy-absorption.In this paper several models are developed based on the observation of microstructures of beetle cuticles. Analyses for capability of energy-absorbing are presented with the ANSYS/LS-DYNA software. Discussions on effects of structural sizes and materials are provided. A comparison is carried out between the present models and cylindrical tubes in terms of dynamic impact response. The results show that the present models absorb more energy and perform in more stability than the tubes.Finally, the application of the present models is discussed using helmet as an energy-absorbing device. To improve its performance, one of the designed models is used as a sandwich lamination combined with an exterior shell. Based on the criterion of helmet test, the ANSYS/LS-DYNA is used to compare the performance of the sandwich helmet with the original helmet under axial crash. The results show that the sandwich helmet not only is light in weight but also is better in protecting human heads.This thesis is funded by The National Science Foundation of China (Projects 10332010, 10721062) and The National Basic Research Program of China (Project 2006CB601205).