Engineering Commons^™

Experiments And Multi-Field Modeling Of Inelastic Soft Materials, Shuolun Wang

Dissertations

Soft dielectrics are electrically-insulating elastomeric materials, which are capable of large deformation and electrical polarization, and are used as smart transducers for converting between mechanical and electrical energy. While much theoretical and computational modeling effort has gone into describing the ideal, time-independent behavior of these materials, viscoelasticity is a crucial component of the observed mechanical response and hence has a significant effect on electromechanical actuation. This thesis reports on a constitutive theory and numerical modeling capability for dielectric viscoelastomers, able to describe electromechanical coupling, large- deformations, large-stretch chain-locking, and a time-dependent mechanical response. This approach is calibrated to the widely-used …

Numerical Investigation Of Flow Through Wide Angle Diffusers, Moududur Rahman

Dissertations

This study is aimed at the development of a computational technique for the prediction of the flow field in wide angle diffusers. The finite element technique is used for the solution of the governing equations. A commercial software package, NISA/3DFlUID, modified for this specific application was used. The parameters affecting the flow field have been identified. For a wide range of variation of these parameters, the effects on the flow field have been examined. This investigation is an exhaustive and comprehensive numerical study of diffuser flows. Such a study will result in substantial improvement in the understanding of the anatomy …

Structural Reliability Using Finite Element Method, Che-Chen Liou

Dissertations

During the last decade, structural reliability theory has been treated in a large number of research papers; therefore, from being a subject only well known by a relatively small number of researchers, it has become an important engineering discipline. From the application point of view, many practical applications have been made successfully.

In this dissertation some important fundamental concepts in statistics and in reliability theory are presented. The concept of failure mode can be defined as: A set of failed elements turn a structure into a mechanism. Usually, a structure has many possible failure modes; therefore, it will be necessary …