Research On The Fatigue Life Of Screw Pump Stator Rubber

Screw pump oil system is usually applied in shallow wells with short service life, it hasbeen a serious question waiting us to solve. Through actual investigation and previous studies,the failure of rubber in a helical rotor pump stator is the main failure form, and the innersurface of the stator rubber refers to fatigue failure, which mainly shows on the leakage ofscrew pump. by finding the fatigue fracture of screw pump, this paper studies on the fatiguelife of the rubber in a helical rotor pump stator,and puts forward improvement schemes andmeasures to optimize the structural parameters of the screw pump, so as to improve thefatigue performance and prolong its lifespan, it has important practical significance forlowering labor intensity in oil field, reducing the cost of production and improving theeconomic benefit.Based on the constitutive relationship of rubber, the material parameters in twoparameter M-R model and Yeoh model are calculated by mathematical methods. In this paper,the stator rubber material tensile test is carried out, using test data fitting analysis of the abovetwo kinds of model to determine that the two parameters of the M-R model is more suitablefor screw pump stator rubber material.This article adopts the method of combining numerical simulation and the theory offracture mechanics to predict the fatigue life of screw pump stator. Finite element analysismodle of standard dumbbell sample (prefabrication incision) is built, using ANSYS to analyse(dangerous parts) the law of stress distribution, the error range is18.67%, the accuracy ismore ideal, and using the methods of numerical simulation and the theory of fracture topredict the fatigue life of screw pump stator rubber is verified on the applicability of the statorrubber material.Taking screw pump GLB120-27as the object of research, according to the needs forestablishing finite element models, the theory of nonlinear finite element is brifely introduced,and respectively compares and analyses the contact stress and equivalent stress between therotor and stator, finally figures out the dangerous position of easily producing fatigue failure.According to the research method mentioned above, using the strain energy release rate of thestator rubber material as fatigue damage parameters to predict the fatigue life of screw pumpstator rubber, the result is708days, and the resulting error is analyzed.