Session: 13-13-01: Simulations of Material Modeling and Behavior Analysis for MEMS Applications

Paper Number: 142573

142573 - An Investigation on the Shape Sensitivity of the Electroactive Membrane With Higher-Order Approximation 

The electroactive polymer is a class of smart material undergoing mechanical deformation when subjected to electric excitation due to its built-in electro-mechanical properties. Hence, electroactive polymers have the capability of changing their size and shape as part of their mechanical response under electric excitation which has made them suitable for various applications including shape memory alloys, soft robotics, biomedical industries, unmanned aerial vehicle wings, and many more. They have great potential to be used for proper control and maneuvering of small-scale aerial vehicles. Therefore, the actual dynamic characteristics of the electroactive polymers in the corresponding aerodynamic environment are required to be properly estimated. The dielectric elastomer is a type of electroactive polymer which is also a smart material having the unique property of undergoing large change in strain under electric stimulation and hence, can rapidly adapt to changes in environmental conditions. They can convert electric stimulation to mechanical deformation and vice versa, which have made them suitable constituent materials for the design of small aerial vehicles. When small-scale aerial vehicles composed of dielectric elastomers are in operation, both the structure and the aerodynamic environment mutually affect the dynamics of each other. In addition, the accuracy of the model used to define the dielectric elastomer material behavior also influences the corresponding dynamic characteristics. Lower-order approximation in the material behavior cannot reflect the proper aeroelastic, aerodynamic, and modal characteristics. Besides, different shapes of the dielectric elastomer material also affect the overall dynamic characteristics. Therefore, in this research, the variations of the dynamic behavior of various shapes of a dielectric elastomer membrane under electric excitation and fluid flow velocities are investigated computationally using a higher-order approximation of the hyperelastic material model. The computational simulation is conducted in the commercially available finite element software COMSOL Multiphysics. First, the modal characteristics of various shapes of the VHB 4910 membrane under electric excitation are analyzed for a certain prestretch ratio. Then, a fully coupled, two-way, fluid-structure interaction model is developed by combining the VHB 4910 membrane of various shapes and the aerodynamic environment to observe the corresponding aeroelastic and aerodynamic characteristics. The aeroelastic characteristics are analyzed for various shapes of the VHB 4910 membrane subjected to different fluid flow velocities under electric excitation. To reflect the nature of the proper aerodynamic environment surrounding the small-scale aerial vehicles, low Reynolds number fluid flow velocities are used in the fluid-structure interaction analysis. Finally, the aerodynamic forces are estimated for various shapes of the VHB 4910 membrane and their variations with different angles of attack and flow velocities are analyzed. A comparison of the aeroelastic characteristics of the VHB 4910 membrane for lower-order and higher-order material approximations is performed. A benchmark case is used to validate the fluid-structure interaction model and the convergence study is performed for ensuring the stability of the model. It has been found that the prestretch ratio and the electric excitation have influences on the overall dynamic characteristics of the VHB 4910 membrane including the aeroelastic response, aerodynamic efficiency, and modal characteristics which can be altered accordingly for proper maneuvering and control of small-scale aerial structures.

Presenting Author: Pratik Sarker Embry-Riddle Aeronautical University

Presenting Author Biography: Dr. Pratik Sarker currently serves as an Assistant Professor of Mechanical Engineering in the Embry-Riddle Aeronautical University, Prescott, AZ, USA. Dr. Sarker earned his PhD and MS in Mechanical Engineering from the University of New Orleans. His current research is on advanced numerical analysis, aerodynamics, vibration and control, thermal analysis, and fluid-structure interaction.

Authors:

Bianca Fernandez Embry-Riddle Aeronautical University
Pratik Sarker Embry-Riddle Aeronautical University
M Shafiqur Rahman Louisiana Tech University