On the design and structural study of a rear swing arm for an electric bike

Abstract

As electric bikes continue to grow in popularity, it is important to ensure that they are equipped with well-designed components. One such component is the rear swing arm (RSA). This study deals with the design and structural analysis of an RSA used for electric bikes. This RSA is composed of two swing arms (one on each side of the bikes), a yoke, a suspension block, and bolts or screws. First, an analytical approach was developed to calculate the initial values for the width and shape of the swing arm. Next, experimental data were used to analyze the response of the RSA and determine the final profile for the swing arms and yoke structure. Finally, the finite element approach was implemented to assess the stress, displacement, and fatigue responses of the RSA when subjected to realistic excitations and conditions. The initial results depicted the following characteristics for the RSA: C-channel profile, 43 mm height, and 2 mm wall thickness. These results implied that the maximum shear force would occur in a region representing approximately 15.5% of the total length of the RSA. Further analysis and calculations showed that this region would decrease to approximately 2.85% of the total length of the RSA. For the final design, the mechanical performance of the RSA was observed to remain acceptable despite the relatively high Von Mises stress values around these singularities. This study assumed the use of 7075 T651 aluminum alloy as the primary material for the RSA.