A NEW METHOD OF CALCULATING ELASTOPLASTICITY CONTACT STRESS OF DRILLSTEM THREAD

Based on the spring model of distribution law of thread axial load and combining with spring model for thread coupling and elastoplastic finite element technique,this paper develops a new method of calculating elastoplastic contact stress of drillstem thread.In the coupling condition,displacement field and stress field of thread coupling area,caused by pre-spinning force and axial tension or compression,are obtained.The method possesses a higher calculating efficiency and meets a certain engineering accuracy.