Mohammad Reza Bayat

Siemens

To design more accurate soft sensors and actuators, there is a significant requirement for the application of complicated deformation conditions. Coupled extension-torsion is a type of deformation which may be utilized in the property characterization of materials with complex behavior such as soft hydrogels. Hydrogels with coupled diffusion and la...

The pH-sensitive hydrogels are a unique class of three-dimensional hydrophilic polymers containing ionic pendant groups on their polymeric network. In response to the external pH variation, these materials span the volume of an aqueous/biological solution and swell without dissolution. Nowadays, the pH-sensitive hydrogels have attracted the growing...

The accurate and efficient design of the bilayer sensors and actuators made of hydrogels are of crucial importance. In this work, a semi-analytical method is developed to solve the swelling induced bending of hydrogel bilayer under plane strain condition. The bilayer consists of a neutral incompressible elastomer layer attached to a hydrogel layer....

Tough pH-sensitive hydrogels with noncovalent bonds have been developed in recent years as a promising structural material. They are involved in many engineering devices and natural phenomena due to their attractive properties. In this paper, we develop an electro-chemo-mechanical theory for swelling and mechanical behavior of tough pH-sensitive hy...

Due to their ability to swell/deswell under alternating pH conditions, pH-sensitive hydrogels present themselves as a potential candidate for controlled drug delivery. In this paper, a coupled electro-chemo-mechanical transient large deformation homogeneous and inhomogeneous swelling theory is developed for pH-sensitive hydrogels. The hydrogel is t...

The pH-sensitive hydrogels are attractive candidates to act like a microvalve in microfluidic devices. In this study, we build a theory for the transient simulation of a pH-sensitive hydrogel-based microvalve. Three fields are involved in the theory, namely the electrochemical, mechanical, and fluid fields. We utilize the Nernst-Planck equation to...

In this paper, a semi-analytical formulation is developed to examine the swelling induced finite bending of a functionally graded hydrogel strip, when the strip is embedded in a solvent bath of an assigned chemical potential. The crosslink density of the hydrogel polymeric network varies through the strip thickness either linearly or exponentially....

Recently, pH-sensitive hydrogels have been utilized in the diverse applications including sensors, switches, and actuators. In order to have continuous stress and deformation fields, a new semi-analytical approach is developed to predict the swelling induced finite bending for a functionally graded (FG) layer composed of a pH-sensitive hydrogel, in...

Employing an analytical method, non-linear low-velocity impact response of carbon nanotube (CNT)-reinforced sandwich cylindrical panels in thermal environments is analysed. Two types of core (i.e. homogenous and functionally graded) are considered for sandwich panels. The face sheets of sandwich panels are multi-layer which consist of CNT-reinforce...

In this article, a pH/temperature sensitive hydrogel based biphasic twisting actuator is presented and studied in various environmental conditions. The actuator consists of a neutral incompressible elastomeric phase attached to pH/temperature sensitive hydrogel phase which twists, when subjected to pH/temperature variation. The deformation of the a...

This paper presents a nonlinear analysis of impact response of nanocomposites cylindrical shells reinforced by single-walled carbon nanotubes (SWCNTs) in thermal environments. The nanotube reinforcement distributions are either uniform or functionally graded in the shell thickness direction. Micromechanical models are employed to estimate the mater...

A two-step perturbation method is used to study the nonlinear behavior of functionally graded carbon-nanotube-reinforced composite cylindrical shells with different filler distributions. Compared with traditional carbon fibers, carbon nanotubes (CNTs) have remarkable mechanical properties. 1 For this reason, there has been a considerable amount of...