Force Analysis of IPMC Actuated Fin and Wing Assembly of a Micro Scanning Device through Two-Way Fluid Structure Interaction Approach

Abstract

In this paper, a methodology is presented to perform force analysis of wing and fin assembly of a micro fish like device through strongly coupled two-way fluid structure interaction approach. The scanning device operates underwater and is towed by a surface vessel through a tow cable. Device fins are actuated by ionic polymer metal composite (IPMC) actuators, an EAP actuator. Fins act as riser, depressor and stabiliser against roll motion of the device. During tow, wing and fin assembly of the device come under hydrodynamic forces. These forces are influenced by fin displacement under IPMC actuation and wing's angle of attack for same towing conditions. To fully investigate wing and fin assembly performance, we must consider the interaction between their structure and fluid (water) and model the coupling mechanism accurately for fluid structure interaction (FSI) analysis. To obtain an accurate prediction to the hydrodynamic forces on wing and fin assembly of the device, it is necessary to conduct dynamic analysis of the surrounding fluid by computational fluid dynamics (CFD). A numerical simulation of three dimensional model of the assembly is performed in ANSYS WORKBENCH by coupling transient structural and Fluid Flow (CFX) analysis systems. The objectives of this study are as follows: 1) To build an accurate three-dimensional CFD model of the wing and IPMC actuated fin 2) To quantify the lift and drag forces acting on the wing and their corresponding coefficients 3) To demonstrate the influence of wing's angle of attack and fin displacement on generation of lift and drag forces. The presented methodology is also applicable to self-propelled micro robots.