Subdomain hybrid cellular automata method for solving car body thickness optimization

Patent metadata

Field	Value
Publication number	US-11080442-B2
Application number	US-202017047405-A
Country	US
Kind code	B2
Filing date	May 8, 2020
Priority date	May 9, 2019
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

A subdomain hybrid cellular automata method for solving car body thickness optimization includes an outer loop and an inner loop: the outer loop is to conduct crash finite element simulation analysis, calculate an output response, and update a cell internal energy density, and update a target mass using a penalty function method; the inner loop is mainly to adjust a cell thickness using a PID control strategy according to internal energy densities of a current cell and neighboring cells thereof, so that a current mass of the inner loop converges to the target mass; and finally the cell internal energy density distribution approaches a step target internal energy density function as much as possible. Step target internal energy density update rules are provided in the inner loop. Cell thickness update rules based on a PID control strategy are provided in the inner loop.

First claim

What is claimed is:

1. A subdomain hybrid cellular automata method for solving car body thickness optimization, comprising the following steps:
S1. building an initially designed crash finite element model for thickness optimization of a car body structure;
S2. building a cellular automata model for the thickness optimization of the car body structure in subdomains, wherein a cell internal energy density distribution for car body framework parts approaches a step target internal energy density function, the car body framework parts are selected from the group consisting of A-pillar, B-pillar, sill, roof-rail, front door, rear door, rear side member, seat crossbeam, front side member rear section, seat rear crossbeam, rear floor front crossbeam, roof front crossbeam, roof middle crossbeam and roof rear crossbeam, and defining thickness variables and field variables;
S3. executing an outer loop: obtaining a cell internal energy density and a constraint function value at a current design point for each of the car body framework parts through simulation analysis, and updating a target mass for each of the car body framework parts using a penalty function method according to an extent, wherein the current design point violates a constraint boundary to the extent;
S4. executing an inner loop:
S4.1. constructing a step target internal energy density function, and updating a target internal energy density for each of the car body framework parts;
wherein a process of constructing the step target internal energy density function is:
S4.1.1. according to subscripts i and j of a cell Ω i,j , defining a sequence number for the cell using id (i, j)={circumflex over (N)} Ω i−1 *(i−1)+j, j∈[1, {circumflex over (N)} Ω i ], {circumflex over (N)} Ω 0 , =0, wherein {circumflex over (N)} Ω i−1 is a number of cells in an (i−1)th subdomain;
S4.1.2. traversing all the cells, and calculating a difference between internal energy densities S id (k) of all the cells and an average S (k) of the internal energy densities in a kth outer loop: ΔS id (k) =S id (k) − S (k) , wherein

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is the average of the internal energy densities of all the cells in the kth outer loop;
S4.1.3. determining “step points” and “step intervals”: traversing all the cells, and when ΔS id (k) *ΔS id+1 (k) <0 is established, defining a subscript id of ΔS id (k) as a “step point,” wherein m “step points” form m+1 “step intervals”;
S4.1.4. updating the “step points” and the “step intervals”: if id i+1 −id i +1<H threshod is established, when i=1, deleting a “step point” id 1 , and a “step interval” is updated from [id 0 ,id 1 ] to [id 0 ,id 2 ]; when i>1, deleting a “step point” id i−1 , and the “step interval” is updated from [id i−1 ,id i ] to [id i−2 ,id i ]; if id i+1 −id i +1<H threshold is not established, retaining the “step points” and “step intervals” of S4.1.3;
S4.1.5 constructing the step target internal energy density function:

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Assignees

• Univ Jiangsu

Inventors

• Duan Libin
• Luo Xin
• Jiang Haobin

Classifications

• G06F30/15 Primary

  Vehicle, aircraft or watercraft design · CPC title

• G06F30/373

  Design optimisation · CPC title

• G06F2119/14

  Force analysis or force optimisation, e.g. static or dynamic forces · CPC title

• G06F2111/04

  Constraint-based CAD · CPC title

• G06F30/23 Primary

  using finite element methods [FEM] or finite difference methods [FDM] · CPC title