NUMERICAL INVESTIGATION OF FATIGUE LIFE ON OPTIMUM AUTOFRETTAGED PRESSURIZED THICK-WALLED CYLINDERS. | ||||
The International Conference on Applied Mechanics and Mechanical Engineering | ||||
Article 105, Volume 13, 13th International Conference on Applied Mechanics and Mechanical Engineering., May 2008, Page 1-17 | ||||
Document Type: Original Article | ||||
DOI: 10.21608/amme.2008.39704 | ||||
View on SCiNiTO | ||||
Authors | ||||
BIN AYOB A.1; ELBASHEER M. K.2 | ||||
1Associate professor. Faculty of Mech. Engineering, Universiti Teknologi Malaysia. | ||||
2Postgraduate student, Faculty of Mech. Engineering, Universiti Teknologi Malaysia. | ||||
Abstract | ||||
ABSTRACT The numerical study presents a procedure to determine the optimum autofrettage pressure for a given operating pressure, so as to achieve the longest fatigue service life of thick-walled cylinders. The study investigates the fatigue life of pressurized cylinders under the effect of applied cyclic internal operating pressure. The cylinders had previously undergone a process of optimum autofrettage to induce a minimum total equivalent stress under the operating pressure. A nonlinear material property with a kinematic hardening was used. Experiments were carried out to validate the numerical results of residual stress where strain gages provided the strain values used to find the hoop stresses present on the outer surface. There was good agreement between the FE simulation and the strain measurement in obtaining residual stresses. The performance of the cylinders was evaluated in terms of fatigue damage accumulation for various levels of autofrettage. The results clearly indicate the importance of autofrettage in increasing the fatigue life. In increasing the autofrettage level, the fatigue life increases first, reaches a maximum optimum level and then decreases. In conclusion, optimum autofrettage level leads to an optimum fatigue life. | ||||
Keywords | ||||
Finite Element; Optimum Autofrettage; Residual stress; Optimum Fatigue Life Prediction | ||||
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