Parametric study of peak circumferential stress at the saddle support

Abstract

A parametric study is presented to determine the peak circumferential stress at the saddle support of an unstiffened horizontal cylindrical vessel. The proposed parameteric formula consists of various multiplying factors. These factors are introduced to account for the influences of saddle flexibility, location of saddle support, support spacing, saddle support angle, saddle width, and vessel dimensions. Parameteric data are generated from a well proven analysis which is based on a contact stress formulation using a complete shell bending theory. The saddle top plate and wear plate, which extend beyond the saddle horn, are important features in lowering the magnitude of peak stress at the saddle support. Therefore, the effect of the saddle top plate and wear plate is studied in great detail. The validity of the proposed parametric formula is corroborated by two sets of examples. The first set relates to rigid saddle supports and the second set relates to flexible supports. Comparsion of results with theory and experiment show that the established parameteric formula is able to predict the peak stress at the saddle support with high degree of accuracy and confidence.