THREE-DIMENSIONAL STRESS ANALYSIS OF A CRANK SHAFT USING FINITE ELEMENT METHOD

Abstract

Internal combustion engines date back to 1876 when Otto first developed the spark-ignition engine and 1892 when Diesel invented the compression-ignition engine. Since its inception internal combustion engine has been playing the role of one of the most important prime movers. With a wide range of applications in different environments, increase in standard of life and decrease in fuel resources, the past two decades have seen an explosion in the knowledge'of engine processes, steadily improving engine specific power and efficiency, reduction in exhaust emisssions and substantial increase in engine sophistication and complexities. With the increasing trend of demands, there is a necessity for considerat!on of analysis/design of existing engine components. The crankshaft is undoubtedly the most important and one of the most expensive single component of an internal combustion engine. The kinematics involved is quite complex as a result of various time varying forces to which it is subjected. Regions of high stress concentrations occur due to abrupt changes in sections, oil holes and sharp ended keyways. As the stresses developed are repeatative, chance of endurance failure is very high. An attempt, therefore, has been made to obtain the stress distributions for the entire crankshaft of an internal combustion engine. In this study, the crankshaft has been treated as a three-dimensional structure. Using finite element method deformations and stresses at various points in the crankshaft are obtained for the dynamic load including gas, inertia and centrifugal forces for steady state conditions.