Research On Pillar Rod Stiffness Ratio Of Hydraulic Press Fatigue Life Reliability

As one of the most important basic equipment in the national heavy industry,hydraulic press is widely used in the key parts of aviation,space flight,navigation,nuclear power,automobile industry and high speed railway.Follow the three beams four columns hydraulic machine has been used in the design of the semi pre-assembled frame structure,the column in the compressor working process in a bending stress state,the majority of small presses and high working frequency lead columns root stress complex,because of fatigue damage and fractures eventually.The research object of this paper is the 6000 ton forging hydraulic press.Its frame structure is to connect the columns with the beams by connecting rod.In the past the design of the pull rods and columns are given by empirical formulas.The preload coefficient of reference range and appropriate stiffness check to press column design is often too conservative,raising the cost and add a lot of weight.At this point,it is necessary to give a reasonable design method for the stiffness ratio between the column and the pull rod.By adjusting the stiffness of the column,the load exerted on the pull bar is affected,and then the stress amplitude on the time load cyclic curve has changed,and the fatigue life is changed accordingly.A finite element model using finite element analysis software PATRAN to build the hydraulic machine pull rod,and the static strength analysis,then through post processing software NASTRAN calculation,get rod stress nephogram and stress concentration region.According to the static strength analysis result file,followed by fatigue analysis software FATIGUE on the hazardous area of fatigue life analysis,adding S-N curve,material information and load information,to get the fatigue life nephogram of rod.Combined with the Weibull probability distribution theory,the reliability of the hydraulic press pull rod is calculated and analyzed,and finally the reliability analysis of the hydraulic press is obtained.This paper through the column pull rod stiffness ratio to analyze pull rod fatigue failure problems,the fatigue life is analyzed by using the finite element software PATRAN and FATIGUE,the reliability of the corresponding rod and through reliability theory to draw some of the fatigue life.It provides a certain theoretical reference for the technical staff in the design of the stiffness of the hydraulic press pull rod and column.