• 대한조선학회지
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• 제17권2호
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• pp.1-10
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• 1980

The optimal plastic design of framed structures has been treated as the minimum weight design while satisfying the limit equilibrium condition that the structure may not fail in any of the all possible collapse modes before the specified design ultimate load is reached. Conventional optimum frame designs assume that a continuous spectrum of member size is available. In fact, the vailable sections merely consist of a finite range of discrete member sizes. Optimum frame design using discrete sections has been performed by adopting the plastic collapse theory and using the Complex Method of Box. This study has presented an iterative approach to the optimal plastic design of plane structures that involves the performance of a series of minimum weight design where the limit equilibrium equation pertaining to the critical collapse mode is added to the constraint set for the next design. The critical collapse mode is found by the collapse load analysis that is formulated as a linear programming problem. This area of research is currently being studied. This study would be applied and extended to design the larger and more complex framed structures.

• 한국CDE학회논문집
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• 제9권4호
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• pp.351-360
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• 2004

An optimal robust design methodology has been developed to minimize the warpage in a decorating panel of monitor molded by the plastic injection. For the associated methodology, the Taguchi's Design Of Experiment (DOE) based on orthogonal arrays and Signal-to-Noise Ratio is combined with commercial simulation tools f3r injection molding. An optimal robust design solution is statistically resulted from the computational simulation. The related experiment was done for evaluations of the warpage in the decorating panel part of monitor. This research showed that the warpage under the applied optimal design conditions was comparatively reduced.

• Design & Manufacturing
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• 제18권2호
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• pp.64-73
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• 2024

The purpose of this paper is to introduce a fusion method that combines the design of experiments (DOE) and machine learning to optimize the bias of plastic products. The study focuses on the plastic motor housing used in automobiles, which is manufactured through plastic injection molding. Achieving optimal molding for the motor housing involves the optimization of various molding conditions, including injection pressure, injection time, holding pressure, mold temperature, and cooling time. Failure to optimize these conditions can lead to increased product deformation. To minimize the deformation of the motor housing, the widely used Taguchi method, which is one of the design of experiment techniques, was employed to identify the injection molding conditions that affect deformation. Machine learning was then applied to various models based on the identified molding conditions. Among the models, the Random Forest model emerged as the most effective in predicting deformation amounts. The validity of the Random Forest model was also confirmed through verification. The verification results demonstrated the excellent prediction accuracy of the trained Random Forest model. By utilizing the validated model, molding conditions that minimize deformation were determined. Implementation of these optimal molding conditions led to a reduction of approximately 5.3% in deformation compared to the conditions before optimization. It is noteworthy that all injection molding outcomes presented in this paper were obtained through robust injection molding simulations, ensuring both research objectivity and speed.

• 대한토목학회논문집
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• 제6권2호
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• pp.111-120
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• 1986

강재(鋼材) 뼈대 구조물(構造物)은 널리 사용(使用)되는 기본적(基本的)인 구조물(構造物)로서, 소성(塑性)힌지의 개념(槪念)을 도입(導入)한 설계(設計) 및 해석방법(解析方法)이 적절(適切)히 적용(適用)되고 있는 경우(境遇)라고 볼 수 있다. 소성해석(塑性解析)의 목적(目的)은 구조물(構造物) 각(各) 부재(部材)의 소성(塑性)모멘트를 알고 있을 때 붕괴하중(崩壞荷重)을 결정(決定)하는 것이며, 소성최적설계(塑性最適設計)의 목적(目的)은 구조물(構造物)의 총중량(總重量)을 최소(最小)로 하는 부도재(部都材)의 소성(塑性)모멘트를 결정(決定)하는 것이다. 본(本) 논문(論文)에서는 소성해석(塑性解析) 및 최적설계(最適設計)를 정적접근방법(靜的接近方法)(static approach)을 사용(使用)하여 Simplex method에 의해 해결(解決)하였다. 소성해석(塑性解析)의 경우(境遇), 종래(從來)의 계산시간(計算時間)을 훨씬 줄일 수 있었으며, 또한 본(本) 연구(硏究)에서 2층 구조물(構造物)의 최적설계시(最適設計時) 구조물(構造物)의 중량(重量)은 탄성설계(彈性設計)와 비교(比較)하여 약(約) 24%가 절약(節約)되었다.

• 약학회지
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• 제35권4호
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• pp.319-325
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• 1991

Aluminum phosphate gel was synthesized by reacting aluminum sulfate as a soluble aluminum salt to tribasic sodium phosphate in this study. The optimal synthesis conditions based on the yield of product were investigated by applying Box-Wilson experimental design. It was found that optimal synthesis conditions were as follows: Reaction temperature; $61~71^{\circ}C$, concentration of two reactants; 12.27~13.83%, concentration ratio of two reactants; [AI$_{2}$(SO$_{4}$)$_{3}$]/[Na$_{3}$PO$_{4}$]= 0.5, reaction time; 10.9~12.1 minutes, drying temperature of product; $60~72^{\circ}C$. Aluminum phosphate gel prepared by the optimal synthesis conditions was suspended with four types of natural and synthetic gums at the concentration of 0.375~1.5wv%. Their Theological properties of aluminum phosphate gels were examined with Haake-Rotovisco RV 20 rotational viscometer. It showed that the higher concentration of suspending agents and lower temperature, the higher viscosity. Aluminum phosphate gel suspended by pectin and agar showed plastic flow with rheopexy, and their gels suspended by sodium alginate and sod. CMC showed plastic flow with thixotropy.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.603-608
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• 2008

It is well known that the topology optimization for plastic problem is not easy since the iterative analyses to evaluate the objective and cost function with respect to the design variation are very time-consuming. The finite element limit analysis is an efficient tool which is possible to predict collapse modes and sequential collapse loads of a structure considering not only large deformation but also plastic material behavior with moderate computing cost. In this paper, the optimum topology of a structure considering large and plastic deformation is obtained using the finite element limit analysis. To verify the constructed optimization code, topology optimizations of some typical problems are performed and the optimal topologies by elastic design and plastic design are compared.

• 한국기계가공학회지
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• 제16권5호
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• pp.105-112
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• 2017

In this study, plastics were deformed after molding due to the characteristics of the material. The Taguchi experimental design method was utilized to find the molding conditions that minimized deformation of the plastic bezel to be assembled in an automotive steering wheel. The injection molding conditions applied to the experimental design method are the melt temperature, cavity plate coolant temperature, core plate coolant temperature, and cooling time. Each condition was divided into five levels, and a total of 25 experiments were planned. However, instead of performing 25 actual molding experiments, the injection molding analysis was performed using the Moldflow program, and the deformation values for each molding analysis were obtained. The optimal molding conditions were obtained from these deformation values. The actual injection molding experiment using optimal molding conditions was compared with the deformation amount of the current molded product. The deformation was measured using a precise 3D scanner. The deformation amount of the molded product under optimal molding conditions was 16.1% lower than the deformation amount of the current molded product.

• 소성∙가공
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• 제5권2호
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• pp.122-129
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• 1996

The main objective of the study is to offer some basic information in relation to optimal shape and dimensions of the rotating band through the development of three-dimensional finite element method for metal forming analysis of the rotating band whose primary function is to impart spin to the projectile. The three-dimensional metal forming analysis of the rotating band has perfor-med by using recurrent boundary conditions. Such design factors as the outside diameter the total length and the profile of the rotating band must be considered carefully in order to design an optimal rotating band. Above design factors can be determined from such available analysis results as the deformed shape and the deformation load. of the rotating band and the normal pressure of the rotating band on a projectile shell. The remeshings are needed to carry out plastic deformation analysis with severe deformation through which the complete process analysis gets possible. The results can be utilized effectively in determining the optimal shape and size of the rotating band.

• Structural Engineering and Mechanics
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• 제4권1호
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• pp.25-35
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• 1996

This paper describes a continuum variational formulation for design optimization of nonlinear structures in the elastic-plastic domain, where unloading and reloading of the structures are allowed to occur. The Total Lagrangian procedure is used for the description of the structural deformation. The direct differentiation approach is used to derive the sensitivities of the various structural response measures with respect to the design parameters. Since the material goes into the inelastic range and unloading and reloading of the structure are allowed to occur, the structural response is path dependent and an additional step is needed to integrate the constitutive equations. It can be shown, consequently, that design sensitivity analysis is also path-dependent. The theory has been discretized by the finite element technique and implemented in a structural analysis code. Mathematical programming approach is used for the optimization process. Numerical applications on trusses are performed, where cross-sectional areas and nodal point coordinates are treated as design variables. Optimal designs have been obtained and compared by using two different strategies: a two level strategy where the levels are defined accordingly the type of design variables, cross sectional areas or node coordinates, and optimizing simultaneously with respect to both types of design variables.

• 한국산학기술학회논문지
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• 제13권12호
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• pp.5709-5715
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• 2012

플라스틱 소재를 사용한 사출성형부품은 차량 경량화뿐만 아니라 충격흡수를 통한 운전자와 보행자 보호, 제품 디자인의 자율성등의 우수한 장점을 가지고 있어 그 사용량이 급속히 증가하고 있다. 유리섬유함유 플라스틱재료를 이용한 레귤레이터 레일의 사출성형시 불량률최소화를 위해 유한요소해석과 실험계획법을 사용하여 성형공정중의 휨변형량(warpage)과 수축변형를 최소화할 수 있는 최적의 성형조건을 제시하고자 한다. 또한 유리섬유의 유동성과 냉각효율의 확보를 위해 최적의 게이트 및 런너방식을 설정한다. 사출금형을 제작하여 제품을 성형제작한 후 휨변형등의 성능확인을 통해 해석방법의 유효성과 최적화의 실효성을 확인하고자 한다.