In this paper a dynamic simulation is conducted on a crankshaft from a single cylinder 4- stroke diesel engine. A three-dimension model of diesel engine crankshaft is created using SOLID WORKS software. Finite element analysis (PEA) is performed to obtain the variation of stress magnitude at critical locations of crankshaft. Simulation inputs are taken from the engine specification chart.

The dynamic analysis is done using F-EAI Software NANAS which resulted in the load spectrum applied to crank pin bearing.This load is applied to the FEE model in NANAS, and boundary conditions are applied according to the engine mounting conditions. The analysis is done for finding critical location in crankshaft. Stress variation over the engine cycle and the effect of torsion and bending load in the analysis are investigated.

Von-misses stress is calculated using theoretically and FEE software NANAS. The relationship between the frequency and the vibration modal is explained by the modal and harmonic analysis of crankshaft using FEE software NANAS.KEYWORDS - Diesel engine; Crank shaft in Nanas; finite element analysis; stress analysis; 1. INTRODUCTION Crankshaft is one of the most important moving parts in internal combustion engine. Crankshaft is a large component with a complex geometry in the engine, which converts the reciprocating displacement of the piston into a rotary motion. This study was conducted on a single cylinder 4- stroke diesel engine.

It must be strong enough to take the downward force during power stroke without excessive bending.So the reliability and life of internal combustion engine depend on the strength of the crankshaft largely. And as the engine runs, the power impulses hit the crankshaft in one place and then another. The torsion vibration appears when a power impulse hits a crank toward the front of the engine and the power stroke ends. If not controlled, it can break the crankshaft. Jinn Mange et al.

[3] analyzed crankshaft model and crank throw were created by Pro/Engineer software and then imported to NANAS software.The crankshaft deformation Was mainly bending deformation under the lower frequency. And the maximum deformation was located at the link between main burglarizing, crank and crank cheeks. Gu Winging et al. [6] researched a three-dimensional model of a diesel engine crankshaft was established by using PRO/E software.

Using NANAS analysis tool, it shows that the high stress region mainly ancestress in the knuckles of the crank arm & the main journal and the crank arm & connecting rod journal ,which is the area most easily broken.Xeroxing Chou et al. [7] described the stress concentration in static analysis of the crankshaft model. The stress concentration is mainly occurred in the fillet of spindle neck and the stress of the crank fillet is also relatively large. Based on the stress analysis, calculating the fatigue strength of the crankshaft will be able to achieve the design requirements.

From the natural frequencies values, it is known that the chance of crankshaft resonant is unlike. This paper deals with the dynamic analysis of the whole crankshaft.