Static and modal analysis of a crankshaft reciprocating driver for reciprocating-airfoil (RA) driven VTOL aircraft

Abstract

New modes of transportation systems are under intensive development because traditional systems fail to become mass transportation means due to their technological limitations. To meet the growing demand for VTOL vehicles, a novel VTOL technology, reciprocating-airfoil (RA) driven VTOL aircraft, had been introduced. The objective of this study is to model a crankshaft to structurally determine the feasibility of using a crankshaft structure as the reciprocating driver of this novel VTOL technology. Unlike the conventional crankshaft IC engines or compressors, the crankshaft system herein is a reciprocating driver to generate long-stroke reciprocating motion of the wings for VTOL vehicle operations. The unique challenges of this study are the exceedingly long crank arms and stringent weight minimizations that require the use of high-strength carbon fiber materials. The crankshaft model is geometrically designed by using SOLIDWORKS design software, and the commercial Ansys Mechanical Solver has been selected for the FEM structural analysis. Based on the nonlinear static analysis results, the maximum stress is developed at the junctions between the main shaft and the middle crank web. However, all of the determined deformation, stress, and strain under the current loading conditions as well as weight requirement is acceptable. Also, according to the modal analysis result, the possible resonance chance is low. In conclusion, this study provides a pathway for the final development of the novel reciprocating airfoil VTOL technology.