A Design Method of Beads in Shell Structure Using Non-Parametric Shape Optimization Method

Author(s):  
Kohei Shintani ◽  
Hideyuki Azegami

The present paper describes a method finding bead shapes in shell structure to increase the stiffness using a solution to shape optimization method. Variation of the shell structure in out-of-plane direction is chosen as a non-parametric design variable. To create beads, the out-of-plane variation is restricted by using the sigmoid function. Mean compliance is used as objective function. The main problem is defined as a linear elastic problem for shell structure. The Fréchet derivative with respect to the out-of-plane variation of the mean compliance is evaluated with the solutions of the main problem and an adjoint problem which is derived theoretically by the adjoint variable method. To solve the bead design problem, an iterative algorithm based on the H1 gradient method is used. Numerical results show the effectiveness of the method.

2018 ◽  
Vol 91 (1) ◽  
pp. 124-133
Author(s):  
Zhe Yuan ◽  
Shihui Huo ◽  
Jianting Ren

Purpose Computational efficiency is always the major concern in aircraft design. The purpose of this research is to investigate an efficient jig-shape optimization design method. A new jig-shape optimization method is presented in the current study and its application on the high aspect ratio wing is discussed. Design/methodology/approach First, the effects of bending and torsion on aerodynamic distribution were discussed. The effect of bending deformation was equivalent to the change of attack angle through a new equivalent method. The equivalent attack angle showed a linear dependence on the quadratic function of bending. Then, a new jig-shape optimization method taking integrated structural deformation into account was proposed. The method was realized by four substeps: object decomposition, optimization design, inversion and evaluation. Findings After the new jig-shape optimization design, both aerodynamic distribution and structural configuration have satisfactory results. Meanwhile, the method takes both bending and torsion deformation into account. Practical implications The new jig-shape optimization method can be well used for the high aspect ratio wing. Originality/value The new method is an innovation based on the traditional single parameter design method. It is suitable for engineering application.


Author(s):  
Yan-yun Yu ◽  
Yan Lin ◽  
Zhuo-shang Ji

In this paper, A parametric structure optimization method, which is called Parametric Structure Shape Optimization Method (PSSOM), is proposed in order to optimize the structure shape of the jack-up platform. According to the characteristic of the jack-up, an approach to create the Parametric Structure Model (PSM) is proposed. The projections of the main structure onto the horizontal plane are used to create the sketch, which is a 2D drawing driven by dimensions. The 3D modeling technique that based on the sketch and feature modeling is used to create the structure model of the jack-up. A meshing procedure is presented to convert PSM into finite element model automatically together with the boundary conditions and the design loads. After calling the FEM solver, the stress and strain for each structure according to any reasonable dimensions could be calculated, and this is the most important foundation of the structure shape optimization design. An optimization design method based on PSM is proposed for the structure optimization design of the jack-up. The genetic algorithm is used to get the optimum dimensions that have better structure strength performance under the premise of that all the other design requirement are satisfied. PSSOM is proved to be practical and high-efficient by the structure optimization of a 300 ft jack-up platform.


2011 ◽  
Vol 80-81 ◽  
pp. 1016-1020 ◽  
Author(s):  
Wei Huang ◽  
Chang Song Ou ◽  
Hai Man Lu ◽  
Zheng Liang Xie

According to the limit working conditions of the gantry milling machine column, this paper adopts Parametric Design Language APDL to set up finite element model and make finite element analysis. Based on the analysis, the topology optimization method of column structure is proposed, and the optimal design method is established to minimize the weight. The finite element analysis is made again to analyze the rearranged column structure. Compared with the design made through experience, optimally designed column can reduce 10% weight. And the critical displacement and maximum stress are not affected.


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