Abstract: Based on the theory of modal analysis on vibration problems ,the simplified model of the engine crankshaft of the material for QT800-6 was established based on the PRO/E . And conduct the model analysis by ANSYS software . So we can get the foregoing 8 orders of the non-zero frequency of the free modal and the constraint modal ,and make a comparison on them . Furthermore ,by viewing the modal shape of the constraint modal ,we can put forward some reasonable suggestions for the structural improvement of the crankshaft.

Key words: engine crankshaft, ANSYS, model analysis