• Title/Summary/Keyword: thickness optimization

Search Result 767, Processing Time 0.031 seconds

Frequency Optimization Using by Feasible Direction Method (유용방향법에 의한 고유진동수 최적화)

  • 조희근;박영원
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2000.10a
    • /
    • pp.410-415
    • /
    • 2000
  • In this paper feasible direction method which is one of the optimization method is adopted to natural frequency optimization. In order to find the optimum design of structures that have characteristic natural frequency range, a numerical optimization method to solving eigenvalue problems is a widely used approach. However most cases, it is difficult to decide the accurate thickness and shape of structures that have allowable natural frequency in design constraints. Parallel analysis algorithm involving the feasible direction optimization method and Rayleight-Ritz eigenvalue solving method is developed. The method is implemented by using finite element method. It calculated the optimal thickness and the thickness ratio of each element of 2-D plane element through the parallel algorithm method which satisfy the design constraint of natural frequency.

  • PDF

Optimization of Incremental Sheet Forming Al5052 Using Response Surface Method (반응표면법을 이용한 Al5052 판재의 점진성형 최적화 연구)

  • Oh, S.H.;Xiao, X.;Kim, Y.S.
    • Transactions of Materials Processing
    • /
    • v.30 no.1
    • /
    • pp.27-34
    • /
    • 2021
  • In this study, response surface method (RSM) was used in modeling and multi-objective optimization of the parameters of AA5052-H32 in incremental sheet forming (ISF). The goals of optimization were the maximum forming angle, minimum thickness reduction, and minimum surface roughness, with varying values in response to changes in production process parameters, such as tool diameter, tool spindle speed, step depth, and tool feed rate. A Box-Behnken experimental design (BBD) was used to develop an RSM model for modeling the variations in the forming angle, thickness reduction, and surface roughness in response to variations in process parameters. Subsequently, the RSM model was used as the fitness function for multi-objective optimization of the ISF process based on experimental design. The results showed that RSM can be effectively used to control the forming angle, thickness reduction, and surface roughness.

Optimization to Control Buckling Temperature and Mode Shape through Continuous Thickness Variation of Composite Material (복합소재의 연속 두께 변화를 통한 좌굴온도 및 모드형상 최적화)

  • Lee, Kang Kuk;Lee, Hoo Min;Yoon, Gil Ho
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.34 no.6
    • /
    • pp.347-353
    • /
    • 2021
  • In this study, we presented a novel size optimization framework to control the linear buckling temperature and several buckling modes of plates, by optimizing thickness values of composite structures for practical engineering applications. Predicting the buckling temperature and mode shape of structures is a vital research topic in engineering to achieve structural stability. However, optimizing designs of engineering structures through engineering intuition is challenging. To address this limitation, we proposed a method that combines finite element simulation and size optimization. Based on the idea that the structural buckling temperature and mode shape of a plate are affected by the thickness of the structure, the thickness values of the nodes of the target structure were set as the design variables in this optimization method; and the buckling temperature values, and buckling mode shapes were set as the objective functions. This size optimization method enabled the determination of optimal thickness distributions, to induce the desired buckling temperature values and mode shapes. The validity of the proposed method was verified in terms of their buckling temperature values and buckling mode shapes, using several numerical examples of rectangular composite structures.

Lightweight Optimization of Infant Pop-up Seat Frame Using DMTO in Static Condition (DMTO 기법을 활용한 정적 하중환경의 유아용 팝업시트 프레임의 경량화)

  • Hong, Seung Pyo;Cha, Seung Min;Shin, Dong Seok;Jeon, Euy Sik
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.21 no.1
    • /
    • pp.102-110
    • /
    • 2022
  • This paper proposes a solution to the problems of manufacturing cost and processability by applying discrete material and thickness optimization (DMTO) and minimizing the use of high-strength, lightweight materials in the optimization process. A simple infant pop-up seat model was selected as the application target, and the weight reduction effect and variation in strength according to the optimization results were observed. In this study, a simplified finite element model of an infant pop-up seat frame was first constructed. The model was used to perform a static structural analysis to verify the weight and strength of each part. The D-optimal design of the experimental method was then used to observe the influence of each part on the weight and strength. This process was applied using discrete thickness optimization (DTO) (which applies high-strength, lightweight materials and optimizes only the thickness) and DMTO (which considers both the material and thickness). The DTO and DMTO results were compared to verify the design method that determines the major parts and simultaneously considers the material and thickness. Accordingly, in this study, an optimal lightweight design that satisfied the strength standards of the seat frame was derived. Furthermore, discretization parameters were used to minimize the application of high-strength, lightweight materials.

Application of Surrogate Modeling to Design of A Compressor Blade to Optimize Stacking and Thickness

  • Samad, Abdus;Kim, Kwang-Yong
    • International Journal of Fluid Machinery and Systems
    • /
    • v.2 no.1
    • /
    • pp.1-12
    • /
    • 2009
  • Surrogate modeling is applied to a compressor blade shape optimization to modify its stacking line and thickness to enhance adiabatic efficiency and total pressure ratio. Six design variables are defined by parametric curves and three objectives; efficiency, total pressure and a combined objective of efficiency and total pressure are considered to enhance the performance of compressor blade. Latin hypercube sampling of design of experiments is used to generate 55 designs within design space constituted by the lower and upper limits of variables. Optimum designs are found by formulating a PRESS (predicted error sum of squares) based averaging (PBA) surrogate model with the help of a gradient based optimization algorithm. The optimum designs using the current variables show that, to optimize the performance of turbomachinery blade, the adiabatic efficiency objective is improved substantially while total pressure ratio objective is increased a very small amount. The multi-objective optimization shows that the efficiency can be increased with the less compensation of total pressure reduction or both objectives can be increased simultaneously.

Topology optimization of variable thickness Reissner-Mindlin plate using multiple in-plane bi-directional functionally graded materials

  • Nam G. Luu;Thanh T. Banh;Dongkyu Lee
    • Steel and Composite Structures
    • /
    • v.48 no.5
    • /
    • pp.583-597
    • /
    • 2023
  • This paper introduces a novel approach to multi-material topology optimization (MTO) targeting in-plane bi-directional functionally graded (IBFG) non-uniform thickness Reissner-Mindlin plates, employing an alternative active phase approach. The mathematical formulation integrates a first shear deformation theory (FSDT) to address compliance minimization as the objective function. Through an alternating active-phase algorithm in conjunction with the block Gauss-Seidel method, the study transforms a multi-phase topology optimization challenge with multi-volume fraction constraints into multiple binary phase sub-problems, each with a single volume fraction constraint. The investigation focuses on IBFG materials that incorporate adequate local bulk and shear moduli to enhance the precision of material interactions. Furthermore, the well-established mixed interpolation of tensorial components 4-node elements (MITC4) is harnessed to tackle shear-locking issues inherent in thin plate models. The study meticulously presents detailed mathematical formulations for IBFG plates in the MTO framework, underscored by numerous numerical examples demonstrating the method's efficiency and reliability.

Linearity Optimization of DG MOSFETs for RF Applications

  • Kim, Dong-Hwee;Shin, Hyung-Cheol
    • Proceedings of the IEEK Conference
    • /
    • 2005.11a
    • /
    • pp.897-900
    • /
    • 2005
  • RF linearity of double-gate MOSFETs is investigated using accurate two-dimensional simulations. The linearity has been analyzed using the Talyor series. Transconductance is dominant nonlinear source of CMOS. It is shown that DGMOSFET linearity can be improved by a careful optimization of channel thickness, gate oxide thickness, gate length, overlap length and channel doping concentration. The minimum $P_{IP3}$ data are compared in each case. It is shown that DG-MOSFET linearity can be improved by a careful optimization of channel thickness, gate oxide thickness, gate length, overlap length and channel doping concentration..

  • PDF

Optimal Thickness Design of Ellipsoidal and Tori-Spherical Pressure Vessel Domes (타원형 및 토리-구형 압력용기도옴의 두께 최적화설계)

  • 이영신;김영완;조원만
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.18 no.3
    • /
    • pp.707-715
    • /
    • 1994
  • This study presents thickness optimization for the pressure vessel domes subject to internal pressure and axial force simultaneously. The considered typical pressure vessel domes are ellipsoidal and tori-spherical domes with skirt and nozzle part. These pressure vessel domes under loading have higher stress concentration on geometric discontinuity parts. Therefore, thickness optimization of axi-symmetric pressure vessel domes is essentially concerned on minimizing this stress concentration. The objective function is minimization of weight of pressure vessel dome. The design variable is thickness of dome and cylinder. Considered constraint is Von Mises equivalent stress. In the optimization procedure, ANSYS code is used. The equivalent and hoop stress of original shape domes are compared with those of optimal shape domes. And optimal thicknesses for pressure vessel domes are presented.

Optimization of Heat Insulation System for a Household Refrigerator (가정용 냉장고의 단열 최적화)

  • 박진구
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.15 no.2
    • /
    • pp.95-102
    • /
    • 2003
  • Optimization for the insulation thickness and external shape of a household refrigerator is peformed in order to minimize thermal load through the insulation wall. The one dimensional conduction heat transfer model is adopted to calculate thermal load. Calculus of variation is employed to optimize the thickness and shape of refrigerator or freezer. The uniform distribution of an insulation thickness and cubed external shape make thermal load minimize. Finally, by using both of the computational and experimental method, the thermal load is minimized for a refrigerator/freezer. It is shown that there exists optimal thickness of insulation walls and external shape for given the external cabinet dimensions and freezer and refrigerator internal volumes, Also, the analytical results are well agreed with the experimental results.

Rayleigh-Ritz optimal design of orthotropic plates for buckling

  • Levy, Robert
    • Structural Engineering and Mechanics
    • /
    • v.4 no.5
    • /
    • pp.541-552
    • /
    • 1996
  • This paper is concerned with the structural optimization problem of maximizing the compressive buckling load of orthotropic rectangular plates for a given volume of material. The optimality condition is first derived via variational calculus. It states that the thickness distribution is proportional to the strain energy density contrary to popular claims of constant strain energy density at the optimum. An engineers physical meaning of the optimality condition would be to make the average strain energy density with respect to the depth a constant. A double cosine thickness varying plate and a double sine thickness varying plate are then fine tuned in a one parameter optimization using the Rayleigh-Ritz method of analysis. Results for simply supported square plates indicate an increase of 89% in capacity for an orthotropic plate having 100% of its fibers in $0^{\circ}$ direction.