Analysis Of Fatigue Characteristics Of Interface Crack With Friction

The research project comes from the Gansu Provincial Natural Science Foundation and the Ministry of Education innovation team project.Because of the effect of external load,the interface of composite component is relatively sliding during the working process.Under the theory of interface fracture,it is necessary to research the fatigue behavior of the interface crack under the condition of friction contact to improve the strength and prolong the service life of the composite.Based on the theory of elasticity,material interfacial fracture and friction,the material interface component as research object,using the finite element simulation method,researching the influence on fatigue crack surface friction properties of material interface crack.The process of modeling,using ANSYS finite element analysis software to establish the composite model and the interface crack model.The crack surface friction coefficient were given by someone after a large number of experiments: f = 0.2~0.6,this paper takes f = 0.2,0.25,0.3,0.35,0.4.Using ANSYS software APDL programming language to conduct singularity of crack tip,calculating crack tip fracture parameter,researching the different trends of crack tip displacement,equivalent stress and stress intensity factor under different friction coefficient of crack surface f and different interface crack size parameters(a/w).Using ABAQUS software to analyze the crack propagation path under different crack surface friction coefficient f and calculate the crack length under f = 0,0.2,0.4,0.6.Then based on the research results of single crack,multi-cracks as the research object,prefabricated interface crack and plane angle is 45 o,set the friction contact,researching the interaction conditions of multi-cracks and achieving some desired results.The results showed that:(1)The crack tip displacement,equivalent stress and stress intensity factor will decrease with the increase of the crack surface friction coefficient;(2)The crack tip displacement,the equivalent stress and the stress intensity factor have a volatility change with the same crack surface friction in different crack sizes.(3)The crack surface friction has an effect on the crack propagation behavior,and the stress distribution decreases with the increase of the crack surface friction coefficient.(4)The crack surface friction can be used to improve the bearing capacity of thestructure and prolong the service life of the mechanical parts.(5)Cnsidering frictional contact,multi-cracks have more effect on the fatigue crack propagation of wheel / rail interface.(6)The value of stress intensity factor KI and KII at the crack tip of wheel/rail interface shows a decreasing trend with the increase of crack number.The stress intensity factor K will get the maximum value when the wheel contact spot is close to the crack.