Session: DA-02-02 Design & Analysis of Piping and Components - 2

Paper Number: 108355

108355 - Theoretical Solution of Obround Shell Under Internal Pressure 

Pressurized enclosures with obround cross sections are common components in the 
petrochemical industries. Since there is no theoretical solution yet, the current analysis of such 
components mainly relies on empirical or numerical analysis methods. In practice, the determination of 
the shell wall thickness requires complex iterations. In the current study, the obround shapes are 
regarded as curved and straight segments with corresponding boundary conditions, respectively. The 
geometry and boundary conditions of each segment are relatively simple. Theoretical analysis of each 
segment was performed individually. A theoretical solution that partially satisfies the deformation 
coordination at the junction of segments is obtained by using existing closed-form solutions. The 
proposed combined solution can accurately describe the stress and displacement distributions of an 
obround shell under internal pressure. Considering the uniqueness of the elastic solution, the proposed 
solution is the closed-form solution for pressurized obround shells. When the straight segment of the 
obround section disappears, the obround becomes a circle, the proposed solution returns to the 
solution of cylindrical shell or Lame’s solution. The proposed solution can be considered as the 
extension of Lame’s solution. The proposed solution provides a new theoretical analysis method. It is 
simpler, more efficient, and more accurate than the empirical methods and numerical analysis current 
used to analyze obround components. It is expected to change the status quo that the analysis of 
obround components relies on empirical formulas and numerical analysis, and to develop a new design 
method for obround components. 

Presenting Author: James Rust propak systems ltd

Presenting Author Biography: Over 40 years of working experience in mechanical engineering.

Authors:

Yao Jin Propak systems Ltd.
James Rust propak systems ltd