Fatigue failure analysis of bike crank arm using solidworks simulation

Abstract

Fatigue analysis probes how cyclic random service loads can often lead to catastrophic structural failure of the component. In this research work the crank bar design of a Bike is validated for Fatigue analysis using SOLIDWORKS Simulation which enables designers to simulate Fatigue failure of the component using Stress Life (SN) method that is based upon standard material test to failure. Aluminum 6061 - T6 material is used in the design and Fatigue SN curve table data is taken from the SOLIDWORKS material library which is derived from material elastic modulus based on ASME Austenitic Steel curves. The crank arm length is 10 in and width is 1.5 in with overall constant thickness 0.8 in and crank mid-section thickness equals to 0.2 in. First the design is analyzed for Static strength by applying the bearing load of 350 lbs. The maximum VonMises stress calculated was 106.61 MPa which is below the allowable yield strength of the material 275 MPa. A fully reversible alternating stresses equivalent to static VonMises stress is loaded for 100,000 cycles which is the required life of the component. The total life calculated was 69,158 cycles which is less than 100,000 cycles and factor of safety is 0.93. The conclusion was the component has to be redesigned for Fatigue strength.