Fracture Analysis And Improved Design To JZH25 Homogenizer Crankshaft Based On Finite Element

The crankshaft is an important part of the homogenizer.Its strength and rigidness have direct influence upon the properties of the whole machine.Since the structure and the shape of the crankshaft are complicated and the loads vary periodically,it is difficult to calculate its strength and rigidness using classical mechanics.With the rapid development of computer technology,FEM is widely used in the field of strength and rigidness analysis of the crankshaft. Therefore analysis using FEM and improved designe are presented in this thesis in allusion to the fracture of the crankshaft of JZH25 homogenizer.First,the loads of the crankshaft are analyzed and the critical case is got.The FEM model of the whole crankshaft is built,the stress contor plot of the critical case is obtained by loading,constraining and calculating,the critical point is found.The static and the fatigue safe coefficient of the critical point are tested.The cause of the fracture which is fatigue fracture under low loads due to stress focus is found.Second,three improved improved designed project are put forward based on the fracture cause of the crankshaft.The best improved designed project is obtained by evaluation of grading method.The crankshaft and the belt drive of the best improved designed project are redesigned.The strength and the rigidness analysis of the improved designed crankshaft is presented,the economic analysis of the improved designed homogenizer is carried out.The conclusion is the strength and the rigidness of the improved designed crankshaft and the economy of the improved designed homogenizer can meet the demands entirely.Finally,modal analysis of the improved designed crankshaft is presented.The natural frequencies of the first 8 modes are extracted.The vibrative shapes of the first 8 modes are obtained and the critical speeds of the first 8 modes are calculated.Because the working speed is lower than the critical speeds greatly,the forced vibrations can′t be happened on the improved design crankshaft.