STRUCTURAL ANALYSIS OF CARBON COMPOSITE FRAME FOR FOLDABLE ELECTRIC WHEELCHAIR DEVELOPMENT

摘要

Electric wheelchairs developed so far have difficulties for elderly people to use, because of their bulkiness and heavy weight. To address this problem, this study presents a design for the construction of an electric wheelchair with an application of light duty materials at frame and a foldable structure that can be easily loaded in a narrow space. A structural analysis was performed to evaluate the structural safety of the foldable wheelchair. For the purpose of analysis, a carbon composite was used as the material for the frame; Structure Mechanics Module of COMSOL Multiphysics was used as the analysis software; and for the boundary condition, the lower part of the body frame was fixed, and a load of 150kg was applied to the upper part of the wheelchair. According to the results of the structural analysis, a maximum displacement of 2.869mm occurred at the handle where the carbon composite was applied, and tensile and compressive stress of 103MPa and 107.3MPa, respectively, were measured at the seat part of the wheelchair where the load was applied. The safety factors were 7.5 and 5.5 for tensile stress and compressive stress, respectively. A maximum variation of 0.0872mm occurred at the aluminum wheel shaft, and a maximum variation of 0.2046mm occurred at the joint. The maximum stress was 116.3MPa that corresponded to a safety factor of 2.66; this indicates that the wheelchair can be considered to be structurally safe as the safety factor exceeds the initial target of 2.