Thermal autofrettage is a potential method for generating compressive residual stresses in a thick cylindrical vessel by inducing plastic deformation through a differential temperature between the outer and inner walls, which is then relieved [1]. The outer wall is always exposed to a higher temperature to achieve the desired effect. A few theoretical models analyzing thermal autofrettage exist, assuming that the material properties are temperature-independent [1–3]. This might be reasonably accurate provided the maximum outer wall temperature during autofrettaging is well below the material’s recrystallization temperature. However, in general, the higher temperature greatly affects the material properties. Also, the material’s yield strength and product of Young’s modulus and thermal expansion coefficient influences the yield onset temperature difference in the cylinder. Keeping this in view, the primary focus of the present research is to present the effect of temperature dependent material properties on the thermal autofrettage-induced residual stresses. The influence of temperature dependence on thermal autofrettage-induced residual stresses is numerically demonstrated for materials with high strength, low thermal expansion coefficients, and vice versa. It is observed that the consideration of temperature dependent material properties reduces the level of compressive residual stresses at the inner wall of the cylinder.
Keywords: Thermal autofrettage, Temperature-dependent properties, Plastic zone, Residual stress.
References
[1] Kamal, S. M., and Dixit, U. S., 2015, “Feasibility Study of Thermal Autofrettage of Thick-Walled Cylinders,” ASME Journal of Pressure Vessel Technology, 137(6), p. 061207.
[2] Kamal, S. M., Dixit, U. S., Roy, A., Liu, Q., and Silberschmidt, V. V., 2017, “Comparison of plane-stress, generalized-plane-strain and 3D FEM elastic-plastic analyses of thick-walled cylinders subjected to radial thermal gradient,” International journal of mechanical sciences, 131-132, pp. 744-752.
[3] Shufen, R., and Dixit, U. S., 2018, “An analysis of thermal autofrettage process with heat treatment,” Interntional journal of Mechanical sciences, 144, pp. 134-145.
