Programmable matter is a material whose properties can be programmed to achieve particular shapes or mechanical properties upon command. This is an essential technique that could one day lead to morphing aircraft and ground vehicles. Metamaterials are the rationally designed artificial materials whose properties are not observed in nature. Their properties are typically controlled by geometry rather than chemical compositions. Combining metamaterials with a programmable function will create a new area in the intelligent material design. The objective of this study is to design and demonstrate a tunable metamaterial and to investigate its thermo-mechanical behavior. An integrated approach to the metamaterial design was used with analytical modeling, numerical simulation, and experimental demonstration. The dynamic thermo-mechanical analysis was used to measure base materials' modulus and thermal expansion coefficient as a function of temperature. CPS, the unit cell of the metamaterial, is composed of circular holes and slits. By decomposing kinematic rotation of the arm and elastic deformation of a bi-material hinge, thermo-mechanical constitutive models of CPS were developed and it was extended to 3D polyhedral structures for securing isotropic properties. Finite element based numerical simulations of CPS and polyhedral models were conducted for comparison with the analytical model. 3D printing of …

One of the major goal of the researchers is to reduce energy loss including nanoscale to the structural level. For instance, around 65% of fuel energy is lost during the propulsion of the automobiles, where 11% of the loss happens at tires due to rolling friction. Out of that tire loss, 90 to 95% loss happens due to hysteresis of tire materials. This dissertation focuses on multiscale modeling techniques in order to facilitate the discovery new rubber materials. Enhanced coarse-grained models of elastomers (thermoplastic polyurethane elastomer and natural rubber) are constructed from full-atomic models with reasonable repeat units/beads associated with pressure-correction for non-bonded interactions of the beads using inverse Boltzmann method (IBM). Equivalent continuum modeling is performed with volumetric/isochoric loading to predict macroscopic mechanical properties using molecular mechanics (MM) and molecular dynamics (MD). Glass-transition and rate-dependent mechanical properties along with hysteresis loss under uniaxial deformation is predicted with varying composition of the material. A statistical non-Gaussian treatment of a rubber chain is performed and linked with molecular dynamics in order predict hyperelastic material constants without fitting with any experimental data.