Research On Design And Manufacturing Of Clamping Device For Sucker Rod Fatigue Test

In the fatigue test of type ? sucker rod specimens,the chuck of the clamping device is prone to indentation on the surface of the sucker rod,causing stress concentration at this position,leading to premature fracture of the sucker rod and failure of the fatigue test.Therefore,this paper designs a new sucker rod fatigue test clamping device,in order to effectively reduce the stress concentration at the sucker rod chuck in the fatigue test,and improve the success rate of the fatigue test.Firstly,by investigating the current situation of the clamping device at home and abroad,a new clamping device with a duckbill head was designed.Determine its theoretical model and calculate the yield stress and contact stress of the sucker rod.Theoretical results show that the sucker rod clamped by the device meets the yield requirements and contact requirements.Secondly,use ANSYS software to perform statics analysis on the new and old clamping devices and sucker rods.By comparison,the stress at the sucker rod chuck held by the new device is significantly reduced.After the feasibility of the new device was determined,the finite element analysis of the sucker rod clamped by the new device was compared with the theoretical calculation results to verify the accuracy of the calculation.On this basis,the duckbill head of the new clamping device was optimized and analyzed in structure,and it was determined that the clamping device with inner and outer arcuate duckbill heads had a good clamping effect.Based on the n Code software,the fatigue analysis of the sucker rod clamped by the new device is carried out,and the fatigue life of the sucker rod's weakest part is close to the actual life of the sucker rod.Finally,the inner arc surface,outer arc surface,half-spacing and other parameters of the duckbill head of the new clamping device are optimized.The response surface optimization method and the fmicon function optimization algorithm were used to solve the optimal parameters.After the clamping device model is determined,UG software is used to simulate the manufacturing process of the clamping device.The results show that the main parameters of the new clamping device: the inner arc radius of the duckbill head,the outer arc radius of the duckbill head,and the half-spacing are 9.9mm,10 mm,and 3mm respectively,the clamping effect is the best.Compared with the original clamping device,the maximum stress at the chuck is reduced by 23.6%,which effectively improves the success rate of the fatigue test.