Session: DA-04-01 Inelastic, Nonlinear, and Limit Load Analysis

Paper Number: 123233

123233 - Method for Shape Imperfection Control in Buckling of Ellipsoidal Heads Using a 3d Laser Scanner 

Ellipsoidal heads are commonly used as components of pressure vessels. Shape imperfections such as out-of-roundness, deviations along the meridian, and bulges are caused by the manufacturing process of ellipsoidal heads, especially large-scale ellipsoidal heads assembled from formed segments. The shape imperfections significantly reduce buckling pressure of ellipsoidal heads, and thus it is essential to control shape imperfections. First, we measured the shapes of several ellipsoidal heads using a 3D laser scanner that can provide the actual head shapes with more accuracy. The measured and perfect shapes were compared to determine the head shape imperfections. Based on the analysis results of head shape imperfections, formulas for characterizing shape imperfections obtained from 3D laser scanning were proposed. Then, we established finite element models of ellipsoidal heads containing shape imperfections characterized by the above formulas. Buckling of head models containing shape imperfections was simulated using the arc-length method, considering the material and geometric nonlinearity effects. Finally, we investigated the effects of shape imperfection types and magnitudes and head geometrical parameters on buckling pressure of ellipsoidal heads. By limiting the shape imperfection magnitudes to certain values, the buckling pressure of actual heads will not differ significantly from ideal ones. On this basis, we proposed a new method for shape imperfection control in buckling of ellipsoidal heads using a 3D laser scanner.

Presenting Author: Tao Shen Zhejiang University

Presenting Author Biography: a master’s student at the College of Energy Engineering, Zhejiang University

Authors:

Tao Shen Zhejiang University
Keming Li zhejiang university
Jinyang Zheng zhejiang university