• 대한기계학회논문집A
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• 제29권3호
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• pp.395-402
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• 2005

Recently Multidisciplinary Design Optimization Based on Independent Subspaces (MDOIS), an MDO (multidisciplinary design optimization) algorithm, has been proposed. In this research, an MDO problem is defined for design of a belt integrated seat considering crashworthiness, and MDOIS is applied to solve the problem. The crash model consists of an airbag, a belt integrated seat (BIS), an energy absorbing steering system, and a safety belt. It is found that the current design problem has two disciplines - structural nonlin- ear analysis and occupant analysis. The interdisciplinary relationship between the disciplines is identified and is addressed in the system analysis step in MDOIS. Interdisciplinary variables are belt load and stiffness of the seat, which are determined in system analysis step. The belt load is passed to the structural analysis subspace and stiffness of the seat back frame to the occupant analysis subspace. Determined design vari- ables in each subspace are passed to the system analysis step. In this way, the design process iterates until the convergence criterion is satisfied. As a result of the design, the weight of the BIS and Head Injury Crite- rion (HIC) of an occupant are reduced with specified constraints satisfied at the same time. Since the system analysis cannot be formulated in an explicit form in the current example, an optimization problem is formu - lated to solve the system analysis. The results from MDOIS are discussed.

• 한국전산구조공학회논문집
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• 제16권4호
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• pp.345-351
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• 2003

자동차 산업에서 안전에 대한 법적인 요구 및 시장 수요의 증가에 따라 강도와 경량화라는 안전과 환경에 대한 상반된 목적을 만족시켜야 하기 때문에 일체형 시트의 설계는 점점 더 중요성이 부각되고 있다. 본 연구에서는 미국시험규정 FMVSS210에 따라 외연적 유한 요소해석 프로그램인 LS-Dyna를 사용하여 시트 충돌해석을 수행하였다 하지만 충돌해석은 많은 해석시간을 요구하기 때문에 효율적이고 신뢰성 있는 최적설계기법이 요구된다. 따라서 통계적 기법인 실험계획법과 반응표면모델을 적용하여 많은 해석시간을 요구하는 LS-Dyna해석을 가능한 줄이고 비선형 최적설계 알고리즘을 적용하여 강도와 경량화를 동시에 최적화하고자 한다. 본 연구에서는 실험계획법을 사용하여 최대 변위 및 총중량에 대한 설계영역을 탐색하고 반응표면모델을 구성하여 최적설계를 수행하였다.

• 한국안전학회지
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• 제15권1호
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• pp.80-85
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• 2000

The hydroforming process is rapidly gaining popularity in the sheet metal forming industry. In this study, hydroforming process is applied to the seat back frame. The load-deformation characteristics of seat frame are simulated according to the test requirements by FMVSS. Structural analyses were performed with an analysis package program named I-DEAS for the conventional and the hydroforming seat back frame. The seat back frame made by hydroforming is not only about 23 percent lightweight, but also about 20 percent high strength compared with conventional that.

• 대한산업공학회지
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• 제41권1호
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• pp.74-78
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• 2015

A bus seat is required to be ergonomically designed in terms of its shape and physical properties to increase seating comfort. The present study is intended to develop a systematic bus seat evaluation protocol based on seating comfort. A total of 48 participants evaluated 12 parts (seat belt, recliner, armrest, headrest, upper-back support, lumbar support, seatback bolster, seatback overall, hip support, thigh support, seatpan bolster, and seatpan overall) of 12 bus seats with 17 subjective comfort measures (e.g., convenience of control, suitability of size, and overall comfort). Lastly, ergonomic features of shape and physical properties of each seat part were identified based on the subject evaluation analysis results. The developed bus seat evaluation protocol can be applied to evaluate various types of seats.

• Industrial Engineering and Management Systems
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• 제10권3호
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• pp.185-190
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• 2011

A driver interacts directly with the car seat at all times. There are ergonomic characteristics that have to be followed to produce comfortable seats. However, most of previous researches focused on either static or dynamic condition only. In addition, research on car seat development is critically lacking although Malaysia herself manufactures its own car. Hence, this paper integrates objective measurements and subjective evaluation to predict seat discomfort. The objective measurements consider both static and dynamic conditions. Steven's psychophysics power law has been used in which after expansion; ${\psi}\;=\;a+b{\varphi}_s^{\alpha}+c{\varphi}_v^{\beta}$ where ${\psi}$ is discomfort sensation, ${\varphi}_s^{\alpha}$ is static modality with exponent ${\alpha}$ and ${\varphi}_v^{\beta}$ is dynamic modality with exponent ${\beta}$. The subjects in this study were local and the cars used were Malaysian made compact car. Static objective measurement was the seat pressure distribution measurement. The experiment was carried out on the driver's seat in a real car with the engine turned off. Meanwhile, the dynamic objective measurement was carried out in a moving car on real roads. During pressure distribution and vibration transmissibility experiments, subjects were requested to evaluate their discomfort levels using vehicle seat discomfort survey questionnaire together with body map diagram. From subjective evaluations, seat pressure and vibration dose values exponent for static modality ${\alpha}$ = 1.51 and exponent for dynamic modality ${\beta}$ = 1.24 were produced. The curves produced from the $E_{q.s}$ showed better $R_{-sq}$ values (99%) when both static and dynamic modalities were considered together as compared to Eq. with single modality only (static or dynamic only R-Sq = 95%). In conclusion, car seat discomfort prediction gives better result when seat development considered both static and dynamic modalities; and using ergonomic approach.

• 산업기술연구
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• 제28권A호
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• pp.71-74
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• 2008

Belt Integrated Seat(BIS) has many advantages compared to the existing seats. Due to the development of materials and manufacturing technology, BIS, which has been used restrictely in the past, has gone through a rapid growth. As a result, its advantages have gained attention and the possibility of replacing the existing seats has grown. The need to develop BIS has risen and presently joint development with associated industries is in progress. For its first goal, the development and research of Recliner sensor has been selected. Recliner sensor is an essential part of the BIS in which the belt is incorporated onto the seat. In seat-belts, there is an inclination sensor which locks the belt according to the angle of a car. Because the inclination sensor can change frequently depending on the back of seat, a device which can enhance the inclination sensor according to the angle of the back of seat. It is the Recliner sensor that play's this role. Studies on Recliner sensor within and outside Korea has not yet made a salient progress, and due to this fact, the joint development has made a start by benchmarking other company's products. Currently, in other to set the course of the development, a research in patents and various other information is being done. In addition, for the purpose of developing a product which will be compatible with the existing products, a prototype will be made and tested before a new product makes its launching on the market.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.383-386
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• 2002

This paper reports on the fluid flow simulation results of an active microvalve. The mechanical and fluidic analysis are done by finite element method. The designed structure is normally closed microvalve using buckling effect, which is consist of three separate structures; a valve seat die, an actuator die and a small piezoelectric actuator. It is confirmed that the complete laminar flow and the lowest flow leakage are strongly depend on the valve seat geometry. In addition, turbulent flow was occurs in valve outlet according to increase seat dimension, height and inlet pressure. From this, we was deducts the optimum geometry of the valve seat and diaphragm deflection that have an great influence fluid flow in microvalve. Thus, it is expected that our simulation results would be apply for constructing integrated chemical analyzing system or drug delivery system.

• 대한기계학회논문집A
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• 제24권7호
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• pp.1779-1786
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• 2000

Most of traditional design processes of mechanical parts are regarded as sequential and discrete, since different kinds of softwas should be introduced. In this paper, we develop an integrated fram ework for virtual design and performance testing of an automobile seat. The system is composed of four modules, i.e. CAD, static analysis, dynamic analysis, and draft drawing module. In the CAD module, PRO/ENGINEER 3D seat model is created using parameters to be modified with the result of static and dynamic analysis. In the static analysis, headrest tere used in each design stage make it difficult to feedback their results to upstream process. These discrete processes may result in time loss and cost rise. In recent years, life cycle of product is reduced. To have competence with others, new concept design processt is simulated using ANSYS. In the dynamic analysis module, FMVSS201 test is simulated using DADS. Overall data flow is controlled by Motif. The advantage of the system is that even a novice can perform and review the whole design process, without a good hand at professional design/analysis S/W in each stage. The system also provides a virtual design space, where engineers in different development stage can access common data of design models. The concept could be applied to other fields and it could reduce time and money required in design process.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.933-937
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• 1995

The design of injection molded prlymeric parts has been done empirically, since it requires profound knowledge about the moldability and causal effects on the properties of the parts. This study shows CAE approach for the design of the seat frame of fiber-reinforced composite material in order to realize the concept os rationsl design for the productivity and quality of mold making. The knowledge-based CAE system is constructed by adding the knowledge-basw module for the design evaluation and appropriate CAE programs for mold design analysis in order to provied designers, at the initial design stage, with comprehensive process knowledge for the performance analysis and the design evaluation. A knowledge-based CAE system is a new tool which enables the concurrent design with integrated and balanced design decisions at the initial design stage of injection molding.

• 한국기계가공학회지
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• 제19권7호
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• pp.41-51
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• 2020

This paper presents the development of a robotic system for rehabilitation of the trunk's ability to maintain postural control under different balance conditions. The system, developed with extensive input from rehabilitation and biomedical engineering experts, consists of a seat mounted on a robotic mechanism capable of moving it with four degrees of freedom (3 rotational and 1 translational). The seat surface has built in instrumentation to gauge the movements of the user's center of pressure (COP) and it can be moved either to track the movements of the COP or according to operator given commands. The system allows two types of leg support. A ground mounted footrest allows participation of legs in postural control while a seat connected footrest constrains the leg movement and limits their involvement in postural control. The design evolution over several prototypes is presented and computer aided structural analysis is used to determine the feasibility of the designed components. The system is pilot tested by a stroke patient and is determined to have potential for use as a trunk rehabilitation tool. Future works involve more detailed studies to evaluate the effects of using this system and to determine its efficacy as a rehabilitation tool.