• Proceeding of EDISON Challenge
• /
• 2016.03a
• /
• pp.256-261
• /
• 2016

In this paper, Shape optimal design for a chair with 4 legs and 2 stretchers consisting of stainless steel was conducted. The shape was transformed by identifying stress and deformation for the part of leg and stretcher. In addition, load condition and mesh was designed using Hypermesh. The stress analysis was carried out using CSD_Elast that is one of EDISON program. In seat test, Maximum equivalent stress was showed at the contact part between seat and legs. As a result, a leg cross-section with rectangular and arch was designed. And optimal height of stretcher was found to reduce a deformation. Also, maximum deformation was reduced by designing a stretcher with ellipse cross-section. So, Optimal chair having 4 legs with rectangular cross section and 2 stretchers with ellipse cross section was shown to satisfy the safety ratio.

• Geomechanics and Engineering
• /
• v.17 no.2
• /
• pp.133-143
• /
• 2019

An optimal hydraulic section is critical for irrigated water conservancy in seasonal frozen ground due to a large proportion of water leakage, as investigated by in-situ surveys. This is highly correlated with the frost heave of underlain soils in cold season. This paper firstly derived a practical model for frost heave of clayey soils, with temperature dependent thermal indexes incorporating phase change effect. A model test carried out on clay was used to verify the rationality of the model. A novel approach for optimizing the cross-section of irrigation canals in cold regions was suggested with live updated geometry characterized by three unique geometric constraints including slope of canal, ratio of practical flow section to the optimal and lining thickness. Allowable frost heave deformation and tensile stress in canal lining are utilized as standard in computation iterating with geometry updating while the construction cost per unit length is regarded as the eventual target in optimization. A typical section along the Jinghui irrigation canal was selected to be optimized with the above requirements satisfied. Results prove that the optimized hydraulic section exhibits smaller frost heave deformation, lower tensile stress and lower construction cost.

• Journal of Aerospace System Engineering
• /
• v.8 no.1
• /
• pp.12-17
• /
• 2014

In this paper, optimal design of composite rotor blade cross-section to consider manufacturability was performed. Skin thickness, torsion box thickness and skin lay-up angle were adopted as discrete design variables and The position and width of a torsion box were considered as continuous variables. An object function of optimal design is to minimize the mass of a rotor blade, and various constraints such as failure index, center mass, shear center, natural frequency and blade minimum mass per unit length were adopted. Finally, design variables such as the thickness and lay-up angles of a skin, and the thickness, position and width of a torsion box were determined by using an in-house program developed for the optimal design of rotor blade cross-section.

• Steel and Composite Structures
• /
• v.7 no.1
• /
• pp.53-70
• /
• 2007

This paper presents a analysis of the problem of optimal design of the beams with two I-type cross section shapes. These types of beams are simply supported and subject to pure bending. The strength and stability conditions were formulated and analytically solved in the form of mathematical equations. Both global and selected types of local stability forms were taken into account. The optimization problem was defined as bicriteria. The cross section area of the beam is the first objective function, while the deflection of the beam is the second. The geometric parameters of cross section were selected as the design variables. The set of constraints includes global and local stability conditions, the strength condition, and technological and constructional requirements in the form of geometric relations. The optimization problem was formulated and solved with the help of the Pareto concept of optimality. During the numerical calculations a set of optimal compromise solutions was generated. The numerical procedures include discrete and continuous sets of the design variables. Results of numerical analysis are presented in the form of tables, cross section outlines and diagrams. Results are discussed at the end of the work. These results may be useful for designers in optimal designing of thin-walled beams, increasing information required in the decision-making procedure.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2002.10a
• /
• pp.276-279
• /
• 2002

A problem formulation and solution for design optimization of laminated composite channel section beam is presented in this study. The objective of this study is the determination of optimum section dimensions of composite laminated channel section beam which has equivalent flexural rigidities to flexural rigidities of steel channel section beam. The analytical model is based on the laminate theory and accounts for the material coupling for arbitrary laminate stacking sequence configuration. The model is used to determine the optimal section dimensions of composite channel section beam. The web height, flange width and thickness of the beam are treated as design variables. The solutions described are found using a global search algorithm, Genetic Algorithms (GA).

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.6
• /
• pp.165-175
• /
• 2000

In order to improve the function of a door seal, its section design technique is discussed in this study, Its roles are prevention of an inflow of dusts, noise interception, insulation, wateproof, and the vibroisolating action which reduces vibration between the body and the door of a car while running, and the buffer action which sustain the proper reacting force as the door is closed. In this study, the optimal cross section of a door seal is designed using nonlinear finite element analysis (commercial finete element analysis program EASi-SEAL) and tables of orthogonal arralys with respect to relations between door and door seal to secure the satisfactory airtight property with the minimum force to shut the door.

• Journal of the Korean Society for Advanced Composite Structures
• /
• v.2 no.1
• /
• pp.1-7
• /
• 2011

In this study the optimal stacking section was selected by pendulum impact test for six different stacking sections of the composite safety barrier. The beam cross-section shape was determined through the poll on six different beam cross-section shapes. The six kinds of stacking design for the determined beam cross-section were suggested. CSM, DB, DBT and Roving fibers were used for stacking design. Horizontal beam and 3:1 sloped beam were modeled by using LS-DYNA. The fall impact simulation was carried out by using rectangular pendulum and cylinder pendulum. Optimal stacking section was determined by comparing and analyzing the impact simulation results.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.28 no.4
• /
• pp.1-12
• /
• 2024

In this study, a determination method of structural member section based on Nonlinear behaviors of steel cable-stayed bridges and the Harmony Search algorithm was presented. The Harmony Search algorithm determines the structural member section of cable-stayed bridges by repeating the process of setting the initial value, initializing the harmony memory, configuring the new harmony memory, and updating the harmony memory to search for the optimal value. The nonlinear initial shape analysis of a three-dimensional steel cable-stayed bridge was performed with the cross-section of the main member selected by the Harmony Search algorithm, and the optimal cross-section of the main members of the cable-stayed bridge, such as pylons, girders, cross-beams, and cables, reflecting the complex behavior characteristics and the nonlinearity of each member was determined in consideration of the initial tension and shape. The total weight was used as the objective function for determining the cross-section of the main member of the cable-stayed bridges, and the load resistance ability and serviceability based on the ultimate state design method were used as the restraint conditions. The width and height ratio of the girder and cross-section were considered additional restraint conditions. The optimal sections of the main members were made possible to be determined by considering the geometry and material nonlinearity of the pylons, girders, and cross-sections and the nonlinearity of the cable members. As a result of determining the optimal cross-section, it was confirmed that the proposed analysis method can determine the optimal cross-section according to the various constraint conditions of the cable-stayed bridge, and the structural member section of the cable-stayed bridge considering the nonlinearity can be determined through the Harmony Search algorithm.

• Korean Business Review
• /
• v.6
• /
• pp.135-152
• /
• 1993

The optional market segmentation pricing policy for rooms of hotels are investigated under the assumption of a linear demand function, and for four different situations: (1) single price market, (2) optimal segmentation of the unused capacity of a single-price-maeket, (3) optimal segmantation for all rooms, and (4) opimal segmentation for infiltration from higher priced to adjacent lower priced segments. The purpose of tis study is th show that with proper pricing policy, it would be possible to increase profits considerably. Such a profit increase might be achived by market segmentation coupled with product differentiation, where the different market segments are identified, sperated, and in each segment a different price per room is called for. The different prices are determined based on the specific price elasticity typical for each market segment and the relavant costs. The pricing model implied in this study is based on basic economic pricing theory and optimization techniques. While somewhat complex in its mathmatical solution, it can be easily programmed for use by practitioners, avoiding the need to cope with the technical aspects of the solution. In section II-1, the optimal single-market Single-price policy is evaluated. The optimal strategy under the constraint that only the previously unutilized rooms are segmented is analysed in section II-2, while the optimal strategy without this constraint is determined in section II-3. In section II-4, the optimal market-segmentation pricing policy is derived for the case in which market seperation is allowed for all the rooms under the assumption of custtomer infiltration from each market segment to the adjacent lower priced segment Finally, some considerations relating to the practicality of the model as a decision support tool and the requirements for its implementation are discussed in section III.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.4 no.2
• /
• pp.139-149
• /
• 2000

In the preliminary design stage of prestressed concrete (PSC) box girder bridges, the design factors decided by inexperience designer could heavily affect to the results of final design. There is a possibility that the design ends up with an excessively wasteful design. To achieve an economical design with preventing an excessive design, the optimal design technique has been developed using ADS optimal program and SPCFRAME in this study. The objective function for the optimal design problem is the material cost of box girders and constrained functions are constituted with design specifications and workability. The Sequential Unconstraint Minimization Technique (SUMT) is used for the optimal design in this study. We designed an uniform cross-section bridge and an ununiform cross-section bridge in the same design condition by optimal design technique developed in this study. Analyzing the results obtained for various tendon layouts, we suggest a standard tendon layout which gives the most effective structural behavior.