A method for the optimal design of low-density polymer foam core sandwiches using FEA and multiobjective optimization of design variables

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Çağrı Uzay ◽  
Durmuş Can Acer ◽  
Necdet Geren
Keyword(s):  
Optimal Design ◽  
Load Capacity ◽  
Low Density ◽  
Foam Core ◽  
Multi Objective Optimization ◽  
Polymer Foam ◽  
Multi Objective ◽  
The Core ◽  
Design Variables ◽  
Bending Load

Abstract In this study, a generative method was introduced to determine the optimal design of low-density polymer foam core sandwiches using finite element analysis (FEA) and multi-objective optimization of design variables without needing experiments. The method was also assessed. The sandwich structures were designed based on woven plain carbon fiber fabrics, PVC foam core, and polymer epoxy matrix. The design variables are the core density (40, 48, 60 kg/m3) and the core thickness (16, 20, 25 mm). The sandwich configurations were subjected to FEA under the three-point bending (TPB) loads. The force-reaction curves obtained from FEA were compared to experimental data available in the literature. Excellent agreement was achieved between the experimental and FEA simulated results at the linear elastic region of the curves. Thus, it allowed predicting the bending stiffness of the sandwiches via TPB analysis. Besides, a two-way analysis of variance (ANOVA) was conducted to determine the effects of parameters on sandwich mass and bending load capacity. Multi-objective optimization of design variables was also carried out according to the constructed mathematical models. The method provided in this study eases both designer’s and researcher’s work to obtain the optimal design variables without making costly experiments.

Multi-Objective Optimization of Composite Elliptical Submersible Pressure Hull for Minimize the Buoyancy Factor and Maximize Buckling Load Capacity

2014 ◽  
Vol 578-579 ◽  
pp. 75-82 ◽  
Author(s):  
Fathallah Elsayed ◽  
Hui Qi ◽  
Li Li Tong ◽  
Mahmoud Helal
Keyword(s):  
Parametric Design ◽  
Load Capacity ◽  
Buckling Load ◽  
Multi Objective Optimization ◽  
Element Analysis ◽  
Multi Objective ◽  
Design Variables ◽  
Wide Range ◽  
Conflicting Objectives ◽  
Sophisticated Analysis

Due to the wide range of variables involved and sophisticated analysis techniques required, optimum structural design of composite submersible pressure hull is known to be a challenge for designers. The major challenge involved in the coupled design problem is to handle multiple conflicting objectives. The problem with its proper consideration through multi-objective optimization is studied in this paper. Minimize the buoyancy factor and maximize buckling load capacity of the submersible pressure hull under hydrostatic pressure is considered as the objective function to reach the operating depth equal to 6000m. Finite element analysis of composite elliptical submersible pressure hull is performed using ANSYS parametric design language (APDL). The constraints based on the failure strength of the hulls are considered. The fiber orientation angles and the thickness in each layer, the radii of the ellipse, the ring beams and the stringers dimensions are taken as design variables. Additionally, a sensitivity analysis is performed to study the influence of the design variables up on objectives and constraints functions. Results of this study provide a valuable reference for designers of composite underwater vehicles.

scholarly journals Optimal Design of IPMSM for EV Using Subdivided Kriging Multi-Objective Optimization

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1490
Author(s):  
Jong-Min Ahn ◽  
Myung-Ki Baek ◽  
Sang-Hun Park ◽  
Dong-Kuk Lim
Keyword(s):  
Optimal Design ◽  
Objective Function ◽  
Pareto Front ◽  
Permanent Magnet Synchronous Motor ◽  
Kriging Model ◽  
Superior Performance ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Design Variables ◽  
Interior Permanent Magnet

In this paper, subdivided kriging multi-objective optimization (SKMOO) is proposed for the optimal design of interior permanent magnet synchronous motor (IPMSM). The SKMOO with surrogate kriging model can obtain a uniform and accurate pareto front set with a reduced computation cost compared to conventional algorithms which directly adds the solution in the objective function area. In other words, the proposed algorithm uses a kriging surrogate model, so it is possible to know which design variables have the value of the objective function on the blank space. Therefore, the solution can be added directly in the objective function area. In the SKMOO algorithm, a non-dominated sorting method is used to find the pareto front set and the fill blank method is applied to prevent premature convergence. In addition, the subdivided kriging grid is proposed to make a well-distributed and more precise pareto front set. Superior performance of the SKMOO is confirmed by compared conventional multi objective optimization (MOO) algorithms with test functions and are applied to the optimal design of IPMSM for electric vehicle.

The Finite Element Analysis and the Multi-Objective Optimization Design of Spindle Systems of CNC Gantry Machine Tools

2016 ◽  
Vol 693 ◽  
pp. 243-250
Author(s):  
Zhi Zhong Guo ◽  
Yun Shun Zhang ◽  
Shi Hao Liu
Keyword(s):  
Machine Tools ◽  
Optimization Design ◽  
Multi Objective Optimization ◽  
Element Analysis ◽  
Multi Objective ◽  
Vibration Resistance ◽  
Design Variables ◽  
Force Coupling ◽  
The Finite Element Analysis ◽  
Spindle Structure

It is discovered that the vibration resistance of spindle systems needs to be improved based on the statics analysis, modal analysis and heating-force coupling analysis of spindle systems of CNC gantry machine tools. The design variables of optimization are set according to sensitivity analysis, multi-objective and dynamic optimization design is realized and its designing scheme is gained for spindle structure. The research results show that vibration resistance can be improved without change of the quality and static property of spindle systems of CNC gantry machine tools.

Finite Element Modelling and Multi-Objective Optimization of Composite Submarine Pressure Hull Subjected to Hydrostatic Pressure

2019 ◽  
Vol 953 ◽  
pp. 53-58 ◽  
Author(s):  
Elsayed Fathallah
Keyword(s):  
Hydrostatic Pressure ◽  
Parametric Design ◽  
Epoxy Composite ◽  
Load Capacity ◽  
Optimization Process ◽  
Valuable Insight ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Optimized Model ◽  
Better Than

Excellent mechanical behavior and low density of composite materials make them candidates to replace metals for many underwater applications. This paper presents a comprehensive study about the multi-objective optimization of composite pressure hull subjected to hydrostatic pressure to minimize the weight of the pressure hull and maximize the buckling load capacity according to the design requirements. Two models were constructed, one model constructed from Carbon/Epoxy composite (USN-150), the other model is metallic pressure hull constructed from HY100. The analysis and the optimization process were completely performed using ANSYS Parametric Design Language (APDL). Tsai-Wu failure criterion was incorporated in the optimization process. The results obtained emphasize that, the submarine constructed from Carbon/Epoxy composite (USN-150) is better than the submarine constructed from HY100. Finally, an optimized model with an optimum pattern of fiber orientations was presented. Hopefully, the results may provide a valuable insight for the future of designing composite underwater vehicles.

Multi-objective optimization of a sports car suspension system using simplified quarter-car models

2020 ◽  
Vol 21 (4) ◽  
pp. 412
Author(s):  
Salman Ebrahimi-Nejad ◽  
Majid Kheybari ◽  
Seyed Vahid Nourbakhsh Borujerd
Keyword(s):  
Numerical Solutions ◽  
Suspension System ◽  
Mode Shapes ◽  
Ride Quality ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Characteristic Roots ◽  
Design Variables ◽  
Stiffness Matrices ◽  
Quarter Car

In this paper, first, the vibrational governing equations for the suspension system of a selected sports car were derived using Lagrange's Equations. Then, numerical solutions of the equations were obtained to find the characteristic roots of the oscillating system, and the natural frequencies, mode shapes, and mass and stiffness matrices were obtained and verified. Next, the responses to unit step and unit impulse inputs were obtained. The paper compares the effects of various values of the damping coefficient and spring stiffness in order to identify which combination causes better suspension system performance. In this regard, we obtained and compared the time histories and the overshoot values of vehicle unsprung and sprung mass velocities, unsprung mass displacement, and suspension travel for various values of suspension stiffness (KS ) and damping (CS ) in a quarter-car model. Results indicate that the impulse imparted to the wheel is not affected by the values of CS and KS . Increasing KS will increase the maximum values of unsprung and sprung mass velocities and displacements, and increasing the value of CS slightly reduces the maximum values. By increasing both KS and CS we will have a smaller maximum suspension travel value. Although lower values of CS provide better ride quality, very low values are not effective. On the other hand, high values of CS and KS result in a stiffer suspension and the suspension will provide better handling and agility; the suspension should be designed with the best combination of design variables and operation parameters to provide optimum vibration performance. Finally, multi-objective optimization has been performed with the approach of choosing the best value for CS and KS and decreasing the maximum accelerations and displacements of unsprung and sprung masses, according to the TOPSIS method. Based on optimization results, the optimum range of KS is between 130 000–170 000, and the most favorable is 150, and 500 is the optimal mode for CS .

Approximate Multi-Objective Optimization of Medical Foot Support: Case of 3D Shape Optimization

2009 ◽  
Author(s):  
Shin-ichiro Miyake ◽  
Suguru Nakao ◽  
Masao Arakawa
Keyword(s):  
Physical Therapists ◽  
Daily Life ◽  
Radial Basis Function Network ◽  
Medical Doctors ◽  
Multi Objective Optimization ◽  
3D Shape ◽  
Multi Objective ◽  
Maximum Reduction ◽  
Design Variables ◽  
Function Network

Splayfoot seems not serious diseases. However, it cause fatigue in the daily life. In that sense, if we can solve these problems it might support daily life much comfortable especially for elder people. To support splayfoot, there are some commercial ones. But they just add small amount of support and not made up for each person. Besides, when the height of support is not suitable for patients, it sometimes makes situation worse. We have tried it and measured by using myoelectric potential measurements, and see differences of three patients. Even if we use the same commercial support its effectiveness differs to each other and sometimes it makes worse. Physical therapists make foot support for each patient but they make them owing to their experience. There are studies on the positions of bone of foot and its portrait of the desired positions has been reported by medical doctors. One of them is called Mizuno standard [1]. In the previous study, we tried to design foot support aiming to make portrait of this standard in vertical space. For that purpose, we used approximate multi-objective optimization using Radial Basis Function network. For validation, we used electromyography again. As a result the foot support by the proposed method showed the maximum reduction in integral of myoelectric. However, in the previous study [2], we only used two design variables, and we have only designed vertical phase. Therefore, we have not completely designed the support. In this study, we use 3D spline expression to make support, and try to design 3D shape of support. In validation, the results of approximate multi-objective optimization show the best reduction in integral of myoelectric, and show the effectiveness of the proposed method.

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