Thermo-Mechanical Stresses in the Design and Analysis of Thick-Walled Pressure Vessels

In design and analysis of mechanical and structural components, stresses due to the existence of temperature field in the part cannot be overlooked. In some practical cases, thermal stresses make a significant portion of total stresses. In undergraduate stress analysis courses, the topic of thermal stresses is covered only in cases of uniform temperature rise and in presence of mechanical loads [1], [2]. Stresses induced by means of temperature gradient alone and in the absence of any mechanical loads are completely ignored. Although coverage of thermal stresses is available in advanced textbooks [3, 4, 5, 6, 7], nevertheless, the level of coverage is beyond the scope of undergraduate students’ understanding. To address this important aspect of stress analysis in our undergraduate curriculum, the authors developed a project in the design and analysis of a thick-walled pressure vessel subject to a high internal pressure and a stiff temperature gradient in the cylinder wall, and they assigned a version of it to the students in the senior level machine design class at their university. Students were teamed in groups of three and were given one month to come up with their stress analysis results and design decisions for choice of bolts selected to fasten the cylinder’s caps to its body. The goal of this paper is mainly to present the pedagogical approach of the stress analysis aspect of this project in the cylindrical portion far away from the cap ends.