scholarly journals Research on Torsional Property of Body-In-White Based on Square Box Model and Multiobjective Genetic Algorithm

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yanmei Meng ◽  
Yuan Liang ◽  
Qinchuan Zhao ◽  
Johnny Qin

In order to assess the performance of a vehicle in the conceptual design stage, a square box model was proposed to predict the torsional stiffness and the first-order torsional frequency of Body-in-White. The structure of Body-in-White was decomposed into eight simple structural surfaces, from which a square box model was constructed. Based on the finite element method, modified shear stiffness of each simple structure surface was calculated and the torsional stiffness was obtained. Then, simple structural surfaces of Body-in-White were constructed into an eight degree-of-freedom series spring system to calculate the first-order torsional frequency. Furthermore, a multiobjective genetic algorithm was used to determine the thickness and structural reinforcement of panels with small stiffness, so as to achieve the goal of increasing the stiffness while reducing the mass of the panel. The result shows that the optimal values of thickness are reduced by around 9.9 percent without affecting their performance by the proposed method. Compared to the prediction results obtained with the complicated numerical simulation, the relative error of the square box model in predicting the torsional stiffness is 6.04 percent and in predicting the first-order torsional frequency is 0.95 percent, indicating that the prediction model is effective.

2013 ◽  
Vol 365-366 ◽  
pp. 429-434
Author(s):  
Deng Feng Wang ◽  
Feng Ji ◽  
Shu Ming Chen ◽  
Yu Sheng Li ◽  
Hai Bo Chen ◽  
...  

The implicit parametric method was briefly discussed in this paper. An implicit parametric 3D solid model and a finite element (FE) model of a body-in-white (BIW) were built up by this method. Low order natural vibration frequencies and modes, bending and torsional stiffness of the BIW were analyzed by FE calculation. A good agreement was acquired by comparing the prediction results with the test values. Results indicated that the implicit parametric model of the BIW established could be used for design and development of the BIW in concept design stage of the BIW.


2021 ◽  
pp. 109963622199386
Author(s):  
Tianshu Wang ◽  
Licheng Guo

In this paper, a shear stiffness model for corrugated-core sandwich structures is proposed. The bonding area is discussed independently. The core is thought to be hinged on the skins with torsional stiffness. The analytical model was verified by FEM solution. Compared with the previous studies, the new model can predict the valley point of the shear stiffness at which the relationship between the shear stiffness and the angle of the core changes from negative correlation to positive correlation. The valley point increases when the core becomes stronger. For the structure with a angle of the core smaller than counterpart for the valley point, the existing analytical formulations may significantly underestimate the shear stiffness of the structure with strong skins. The results obtained by some previous models may be only 10 persent of that of the present model, which is supported by the FEM model.


Author(s):  
H Sayyaadi ◽  
H R Aminian

A regenerative gas turbine cycle with two particular tubular recuperative heat exchangers in parallel is considered for multi-objective optimization. It is assumed that tubular recuperative heat exchangers and its corresponding gas cycle are in design stage simultaneously. Three objective functions including the purchased equipment cost of recuperators, the unit cost rate of the generated power, and the exergetic efficiency of the gas cycle are considered simultaneously. Geometric specifications of the recuperator including tube length, tube outside/inside diameters, tube pitch, inside shell diameter, outer and inner tube limits of the tube bundle and the total number of disc and doughnut baffles, and main operating parameters of the gas cycle including the compressor pressure ratio, exhaust temperature of the combustion chamber and the air mass flowrate are considered as decision variables. Combination of these objectives anddecision variables with suitable engineering and physical constraints (including NO x and CO emission limitations) comprises a set of mixed integer non-linear problems. Optimization programming in MATLAB is performed using one of the most powerful and robust multi-objective optimization algorithms, namely non-dominated sorting genetic algorithm. This approach is applied to find a set of Pareto optimal solutions. Pareto optimal frontier is obtained, and a final optimal solution is selected in a decision-making process.


2012 ◽  
Vol 248 ◽  
pp. 69-73 ◽  
Author(s):  
Shu Ming Chen ◽  
Xue Wei Song ◽  
Chuan Liang Shen ◽  
Deng Feng Wang ◽  
Wei Li

In order to know the static stiffness characteristics of the vehicle body in white, the bending stiffness and torsional stiffness of an automotive body in white were tested on a test bench of the static stiffness of an automotive BIW. The bending stiffness and bending deformation of the bottom of the BIW were determined. Also, the torsional stiffness and torsional deformation of the bottom of the BIW were obtained. The fitting curves and equations between loading torque and torsional angle were acquired at clockwise and counterclockwise loading, respectively.


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