Failure Analysis of a Crank Hinge in a Guillotine Machine  

作　　者：A.R.LOKUGE R.J.WIMALASIRI 

机构地区：[1]Mechanical Engineering,Department of Mechanical Engineering Kingston University,London [2]Mechanical Engineering,Department of Mechanical Engineering,The Open University of Sri Lanka,Nawala,Nugegoda

出　　处：《Instrumentation》2021年第4期34-46,共13页仪器仪表学报（英文版）

摘　　要：Guillotine machines are used to cut bulk quantities of paper,often thousands at a time.More the number of papers to be cut at once,more load is required to cut.This machine undergoes a frequent failure of one of its hinges,which prevents the operation of the machine.A combination of torsional forces and bending mo-ments are acting on the hinge when operating.Torsional stresses induced due to the friction between the con-tacting surfaces of the crank rod and the hinge.The bending moment induced due to the alternating motion and the load acted upon the cutting mechanism.The crank transforms the rotational movement into a translational motion of the blade,which results in the formation of a cyclic load in the form of a sinusoidal with a mean value not equal to zero.This leads to fail the hinge in the mode of fatigue.Naked eye observations of the fracture surface reviled a clear failure initiation point and striation marks of crack propagation and a sudden fracture re-gion which evident a fatigue failure due to cyclic loading.To redesign the failed hinged to avoid such failure,it is essential to,(i)define and evaluate the stresses developed by the combined loading condition(ii)understand the nature of the cyclic stress induced.The force acting on the hinge was calculated by the law of conservation of momentum created by the blades'inertia and its'supportive structure.It was understood that the mean stress value of the cyclic load is not equal to zero,the modified Goodman diagram is used.Computational simulations are conducted using Finite Element Analysis(FEA)on the ANSYS fatigue tool.By applying the fatigue analysis theories and conducting FEA for stress analysis,the reason for the failure is revealed and then necessary pre-cautions could be taken to prevent such failures in the future.

关 键 词：Fatigue Fracture Crack Propagation Cyclic Load FEA Mean Stress. 

分 类 号：TS734.7[轻工技术与工程—制浆造纸工程]