Optimization of rigid-plastic shallow spherical shells of piecewise constant thickness

1993 ◽  
Vol 6 (2) ◽  
pp. 134-141 ◽  
Author(s):  
J. Lellep ◽  
H. Hein
Keyword(s):  
Constant Thickness ◽  
Rigid Plastic ◽  
Spherical Shells ◽  
Piecewise Constant

Plastic Analysis of Shallow Spherical Shells

1974 ◽  
Vol 41 (3) ◽  
pp. 593-598 ◽  
Author(s):  
H. M. Haydl ◽  
A. N. Sherbourne
Keyword(s):  
Transverse Shear ◽  
Yield Surface ◽  
Numerical Solutions ◽  
Plastic Yielding ◽  
Rigid Plastic ◽  
Spherical Shells ◽  
Shallow Shells ◽  
Von Mises Criterion ◽  
Plastic Analysis ◽  
Von Mises

Rigid-plastic yielding and postyielding of pressurized shallow spherical shells is considered. The analysis includes the contribution of the transverse shear to yielding. Two approximate numerical solutions are given for several shell configurations. The yield surface used is based on the von Mises criterion. The results show that the effects of geometry changes lead to “geometrical strengthening” and “geometrical weakening” of the shallow shells.

Optimal design of a cylindrical composite panel of piecewise constant thickness

2017 ◽  
Vol 13 (4) ◽  
pp. 568-577 ◽  
Author(s):  
Ernest Belybekyan ◽  
Arevshat Poghosyan ◽  
Hayk Sharkhatunyan
Keyword(s):  
Optimal Design ◽  
Optimal Choice ◽  
Composite Panel ◽  
Constant Thickness ◽  
Physical Parameters ◽  
Strength Increase ◽  
Constant Weight ◽  
Content Type ◽  
Piecewise Constant ◽  
Fixed Weight

Purpose The purpose of this paper is to investigate the problem of optimizing geometrical and physical parameters of a stepped shell that maximize its rigidity and strength for given overall shell dimensions and fixed weight equal to the weight of a shell of constant thickness. Design/methodology/approach A mathematical model of the construction’s stress-strain state is described by solving a system of differential equations for each of the constituent parts of the shell, conjugation conditions on the division lines and boundary conditions. The stated optimization problem is reduced to a nonlinear programming problem, which is solved by the deformable polyhedron method in combination with the method of direct search and using the parallel computing package in the Wolfram Mathematica software application. Findings As follows from the results of the calculation, optimizing the shell parameters allows for a substantial increase in rigidity (decrease of the greatest deflection) and strength (increase of the load-carrying capacity) of the shell of constant stepwise thickness, as opposed to a shell of constant thickness, with constant weight and dimensions. Originality/value A problem of optimal design of a cylindrical composite panel of piecewise constant thickness is solved in the presented work. Numerical examples demonstrate that a substantial increase in rigidity and strength of a stepped composite shell can be achieved by the optimal choice of its geometrical and physical parameters.

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