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Full-Text Articles in Engineering Science and Materials

Dielectric Elastomer Composites: Macroscopic Behavior And Instabilities, Morteza Hakimi Siboni Jan 2014

Dielectric Elastomer Composites: Macroscopic Behavior And Instabilities, Morteza Hakimi Siboni

Publicly Accessible Penn Dissertations

Dielectric Elastomers (DEs) are an interesting class of active materials that can exhibit coupled electrical and mechanical behaviors, for example they can respond to an external electric field by changing their shape or size. This unique property is known as electrostriction, and makes such materials promising candidates for a wide range of practical applications, and therefore there is a need for the design of DEs with enhanced electromechanical couplings. In this work we investigate the possibility of enhancing the electrostriction by making composites consisting of one or more family of filler phases in a soft dielectric host.

We use homogenization ...


Nanoparticle-Shelled Bubbles For Lightweight Materials, Teresa Brugarolas Brufau Jan 2014

Nanoparticle-Shelled Bubbles For Lightweight Materials, Teresa Brugarolas Brufau

Publicly Accessible Penn Dissertations

Lightweight materials that are mechanically robust are of great interest in automotive, aerospace, and construction industries. However due to the nature of materials, it is challenging to obtain materials that have high strength, stiffness and toughness, and light weight simultaneously. One approach that tries to address this limitation is the use of composite materials containing hollow microparticles, also known as syntactic foams. The incorporation of hollow microparticles decreases the density of the material at the same time that increases its specific strength. Conventional methods of fabrication of hollow particles involving bulk reactions result in high heterogeneity in geometry as well ...


Overall Mechanical Response Of Soft Composite Materials With Particulate Microstructure At Finite Strains, Reza Avazmohammadi Jan 2014

Overall Mechanical Response Of Soft Composite Materials With Particulate Microstructure At Finite Strains, Reza Avazmohammadi

Publicly Accessible Penn Dissertations

Many soft, composite materials manufactured or found in nature consist of a homogeneous matrix phase and a random distribution of micron-sized particles in the matrix. Examples among engineering materials include reinforced elastomers, microgel suspensions and polymer-matrix composites, whereas biological tissues and fluids, such as intervertebral disc and blood, provide examples of natural materials. In this thesis, we present homogenization-based models for the overall constitutive behavior of such composite materials when subjected to mechanical loadings. These models account for the constitutive nonlinearities associated with the local behavior of the matrix and particle phases, as well as for the nonlinearities associated with ...