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Relative sensitivity method for optimizing shapes of discrete truss structure and continuum structure

A truss structure, relative sensitivity technology, applied in the direction of instrument, adaptive control, control/regulation system, etc., can solve the problem of small number of discrete variables and so on

Inactive Publication Date: 2010-10-13
GUILIN UNIV OF ELECTRONIC TECH
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the method uses relative sensitivity to determine the iterative direction, it can avoid converging on pseudo-extreme points and has strong robustness, thus solving the hybrid discrete optimization problem widely existing in the shape optimization of engineering structures
In actual engineering mixed discrete optimization problems, the dimension of discrete variables is generally less than that of continuous variables

Method used

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  • Relative sensitivity method for optimizing shapes of discrete truss structure and continuum structure
  • Relative sensitivity method for optimizing shapes of discrete truss structure and continuum structure
  • Relative sensitivity method for optimizing shapes of discrete truss structure and continuum structure

Examples

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Embodiment 1

[0050] This embodiment is a relative sensitivity method for optimizing the shape of a continuum structure. figure 1 Shown is a schematic diagram of the structure of the pressure vessel continuum. Including the coupling of two types of variables, the structural shape and the cross-sectional size of the pressure vessel, the best target performance is the minimum sum of material cost and welding cost, and the design variable is: X=[x 1 , x 2 , x 3 , x 4 ]=[T s ,T h , R, L], where x 1 , x 2 is the structural section variable, x 3 , x 4 Structural boundary shape variables. The flow chart of the implementation steps of the relative sensitivity method for the shape optimization of the continuum structure pressure vessel in this example is as follows Figure 5 As shown, the details are as follows:

[0051] Step 1. Establish an optimization model for the coupling of two types of variables, the shape of the continuum structure and the size of the section.

[0052] ...

Embodiment 2

[0088] This embodiment is a relative sensitivity method for shape optimization of discrete truss structures. Figure 4 Shown is a schematic diagram of a discrete truss structure with 4 bars and 5 nodes in space. It is known that the modulus of elasticity of each rod is E=6.9×10 6 N / cm 2 , density ρ=0.028N / cm 3, allowable stress [σ] = 17244N / cm 3 , the displacement constraint is that the displacement of node 1 in the x, y, z, and three directions does not exceed 0.77, 1.27, and 1.02, respectively. The working condition is that the forces at node 1 are: Px=1.78×10 5 N, Py=4.45×10 5 N, Pz=-1.34×10 5 N. The best target performance in this example is to minimize the total weight of the truss structure. The two types of variables included in the structural shape and cross-sectional size are the node coordinate design variables x 1 ,y 1 ,z 1 , member section variable A 1 , A 2 , A 3 , A 4 .

[0089] The implementation steps of the relative sensitivity method for shape...

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Abstract

The invention discloses a relative sensitivity method for optimizing shapes of a discrete truss structure and a continuum structure. In the method, for the problem of variable coupling optimization of the shapes of the discrete truss structure and the continuum structure containing structure shapes and sectional dimensions, the iteration direction of a mixed discrete optimizing problem is determined according to the relative sensitivity of a target and restriction, and the sectional dimension and structure shape variables which can lead the best target performance of the discrete truss structure and the continuum structure are calculated. The regulation for determining the iteration direction is as follows: in a feasible region, the iteration direction is the coordinate direction which enables a target function to decrease most rapidly and the restriction to increase least; and out of the feasible region, the iteration direction is the coordinate direction which enables the target function to increase least and the restriction to decrease most; and if the variable corresponding to the iteration direction is a continuous variable, the discrete variable value is set to be a constant, and all the continuous variables are optimized according to a continuous variable optimization method.

Description

technical field [0001] The invention belongs to the field of structural shape optimization design, in particular to a relative sensitivity method for shape optimization of discrete truss structures and continuum structures. Background technique [0002] Structural shape optimization design needs to comprehensively consider the coupling of shape and cross-section variables. Since the cross-sectional area can only take discrete values, structural shape optimization is a nonlinear mixed discrete variable optimization problem, and it is difficult to solve it. Therefore, the research and development of effective hybrid discrete optimization algorithms has always been an important topic in structural design optimization. Mixed discrete variable optimization methods can be summarized into the following categories: 1) Methods based on continuous variable optimization methods, such as rounding method, quasi-discrete method and discrete penalty function method. Such methods may lead ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G05B13/04
Inventor 蒋占四向家伟吴义忠蒋慧陈东弟
Owner GUILIN UNIV OF ELECTRONIC TECH
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