We measure the infrared spectra of polyethylene nanostructures of height 15 nm using atomic force microscope infrared spectroscopy (AFM-IR), which is about an order of magnitude improvement over state of the art. In AFM-IR, infrared light incident upon a sample induces photothermal expansion, which is measured by an AFM tip. The thermomechanical response of the sample-tip-cantilever system resu...

In 1900 Otto Lehmann found that a cholesteric liquid crystal (CLC) subjected to a temperature gradient parallel to the cholesteric axis started rotating [1]. This phenomenon, thermomechanical coupling, was explained by Leslie in 1968 [2], who regarded it as a linear transport process, where a temperature gradient parallel to the cholesteric axis in addition to driving a heat flow also induces a...

The purpose of this work is to present a study of the thermomechanical behavior of the automotive disc brake during the braking phase. The first analysis is performed on the disc-pad model without the presence of thermal properties. Structural performance of the disc-pad model such as deformation and Von-Mises stress is predicted. The case of thermoelasticity on the same model with the inclusio...

Due to thermomechanical hysteresis in solids undergoing martensitic type of structure transformations the macroscopic strain and volume fraction of martensite are not a single-valued function of stress and temperature, but they become functions of the process of their change. Some of the phenomenological approaches describing ma~n thermomechanical properties of shape-memory alloys (SMA) connect...

Accurate prediction of the thermomechanical cyclic behavior of joints and interfaces in semiconductor devices is essential for their reliable design. In order to understand and predict the behavior of such interfaces there is a need for improved and unified constitutive models that can include elastic, inelastic, viscous, and temperature dependent microstructural behavior. Furthermore, such uni...

While the existing thermomechanical constitutive models can predict the behavior of SMAactuated systems in most cases, in this study, we have shown that there are certain situations in which these models are not able to predict the behavior of SMAs. To this end, a rotary SMA-actuated robotic arm is modeled using the existing constitutive models. The model is verified against the experimental re...

A thermomechanical boundary value problem and constitutive model are presented for a shape memory alloy (SMA) wire under uniaxial loading. The intent is to develop a one-dimensional continuum model of an SMA element that includes all the relevant thermomechanical couplings and is suitable for inclusion in finite element analyses. Thermodynamic relations are derived from phenomenological conside...

We show that the continuous cholesteric fingers, which form in homeotropic samples at the unwinding temperature of the cholesteric phase, drift and spiral when they are subjected to a temperature gradient. This phenomenon is attributed to the appearance of a Lehmann thermomechanical torque. Measurements of the finger drift velocity on both sides of the compensation temperature of a cholesteric ...