The Analysis On Fatigue Life Of All-terrain Vehicles’ Welding Frame

The structure on the condition of alternate load will cause the fatiguedamage,especially for welding structure.In a long-term bear dynamic load workingcondition,the fatigue life than the parent material are more prone to fatiguedamage.Theoretical study and engineering application of testing the mechanical structureand the fatigue life of welded structure is mainly depend on experiments,due to themechanical structure and welding structure by the geometry and size. manufacturingprocess and other factors,even with a batch of part test to obtain the fatigue life is alsodifferent.With the rapid development of computer technology, computer assistantengineering design in the modern manufacturing the position becomes more an moreimportant.Enterprises in order to shorten the development cycle，reduce developmentcost,to obtain a high quality design products are often selected by virtual prototypetechnology for new products for anti fatigue design,on the need to improve the prototypeperformance check.In this paper,using the computer aided engineering (CAE) technology, to weldedframe of a certain type of all-terrain motorcycle with four wheels, the base metal andwelded join of frame are respectively the fatigue life analysis and comparison.First,this paper established a finite element model of frame,through experimentalmodal correction,the frame of bending and torsion stiffness,and in the vehicle based onfinite elements, analysis of the frame under various practical condition of strength.Based on the modal stress recovery theory,numerically modal analysis on the frameof the vehicle,received frame modal stress file as the fatigue life,analysis of the load; themodal neutral file (MNF file) as the frame modal information transmission for vehicledynamics model using.By the adams software we established a vehicle rigid-flexible coupled dynamicsmodel. The simulation result has been the stress time history file (DAC file) of weldedframe fatigue life analysis needed.Finally,based on the fatigue life prediction theory and welded structure fatigue theory,in the MSC Fatigue fatigue analysis software S-N and seam-weld module,the frame bodyand frame welded joint are respectively fatigue life analysis and comparative analysis foran all terrain vehicle product anti fatigue design reference.