Recently, there has been an increasing demand for independent suspension systems in commercial vehicles, and various researches related to this trend are currently underway. In this study, as part of an effort to localize the independent suspension system for commercial vehicles, a preceding study was conducted to convert the existing forging process into a casting process. The structural stability of the developed product was evaluated by performing stress analysis on both forging and casting materials. In order to compensate for the low yield characteristics of the casting material, design improvements were made to lower the maximum stress level based on numerical simulations.Additionally, Lightweight design was performed, capitalizing on the inherent design flexibility offered by casting products. As a result, it was confirmed that the developed product exhibited similar stress characteristics level to the existing product, along with a weight reduction of approximately 5%.

Gas springs applied to various industrial fields are generally composed of a cylinder, a piston rod, a cover, and a seal mount. Because of the thin wall of the cylinder, small gas springs are manufactured using a roller forming process that presses the cylinder wall into a groove of cover in the cylinder. In this study, finite element analysis and process design of roller forming are performed to systematically manufacture the small gas spring and develop a roller forming machine. In order to perform roller forming analysis, tensile tests of structural steel pipe are performed and mechanical properties are analyzed. Roller forming process parameters such as radius and depth of roller grooves are derived using the incompressible condition of plastic deformation theory and the results of finite element roller forming analysis. Using the derived roller shape, a roller forming machine is developed and prototypes of the small gas spring are manufactured. Finally, the dimensional accuracy of the manufactured gas spring prototypes is analyzed through three-dimensional shape measurement.

In this study, we used a numerical analysis program to study the molding conditions that affect the flow rate at the time of injection, using a spiral mold, which is mainly used for the evaluation of the flow rate of plastic resin. The mold temperature, melt temperature, and flow rate are composed of experimental factors. The three plastic forming factors were divided into five to six levels each. Since then, changes in the flow rate temperature were analyzed as the level of each forming factor increased. Experiments showed that all three forming factors increased the filling length of the spiral mold and the temperature of the flow front by a total of 34.53°C, melt temperatures increased the temperature of the flow front by a total of 34.53°C, the temperature increased by the flow rate was 23.5°C, and the temperature increased by the mold temperature was 1.99°C. It was shown that the melt temperature was the largest, followed by the flow rate and mold temperature. It was also possible to check the effect of plastic forming factors on the speed of the flow front.

Metal bodies have generally been produced through machining process, even the smallest parts that are assembled and mounted on the metal body. In this study, we will study the process of manufacturing parts called SIM Tray through compound forging process instead of cutting. The process of replacing a series of SIM Tray production process with a composite forging process by simulating the forming process using DEFORM-3D and making process design, mold design, mold fabricating.

유니버설 조인트는 두 회전 축 사이에서 힘을 전달하는 구성 요소이며, 구동축과 피동축이 나란히 정렬되지 않아도 나란히 정 렬되지 않아도 동력전달이 가능하게 하며 각도 변화가 있는 전동축에서도 효율적으로 동력을 전달시키는 부품으로서 자동차의 동력전달 장치에서 많이 적용되고 있다. 차량의 경량화를 위해 고강도 알루미늄의 사용이 증가하고 있다. 본 연구에서는 알루미늄 6061 재질을 사용하여 유니버셜 조인트 샤프트를 성형하기 위해 환봉 압출, U-Shape 성형, Spline 성형 등에 대한 단조 해석 연구하였다. Bar Extrusion 성형 시 23.3Ton, U-shape 성형 시 62.2Ton, Spline 성형 시 3.2Ton, 총 Cycle Time 226sec의 성형 조건을 산출하였으며, 이를 적용하여 알루미늄 유니버셜 조인트를 제작하였다. 비틀림 시험을 통해 토크값은 평균 425.8(N・m), 비틀림 각은 평균 171.6° 의 실험값을 통해 기존 제품에 비해 단조 제품이 12.0∼14.4%의 비틀림 성능의 향상을 보였다.

SUS hexagonal bar have been widely used to manufacture the hexagonal bolt/nut, adapter and fittings. Raw SUS circular bar is used to make SUS hexagonal bar using drawing system. The purpose of this study is to investigate the characteristics, for instance, such as stress, strain and reduction ratio of area for bar. As the results, it was confirmed that the maximum stresses were occurred at edge of hexagonal bar, thus it could be worked as residual stress of hexagonal bar. The phenomenon of spring back was almost no found in all parts of hexagonal bar. Furthermore it showed that the reduction ratios of area were about mean 26% when SUS circular bar was changed to SUS hexagonal bar in this study.

본 논문은 Shaped charge jet(SCJ)의 관통 과정을 유한요소해석을 통해 모사하여 제트 입사속도, 관통률 그리고 관통량 증분과 같은 물리량들을 획득하였다. 이 물리량들을 hydrodynamic 이론에 적용하여 입사 제트 속도의 효율을 분석한 결과, 입사 속도가 빠른 제트의 관통 효율은 이어지는 느린 제트에 비해 높은 것을 확인하였다. 이 효율은 hydrodynamic limit (HL) 미만인 제트인 경우 큰 폭으로 감소하였다. 한편, 시간에 따른 관통량 증분과 제트 소모량의 비교는 SCJ의 이론적인 관통현상 분석을 위해서는 길이 연장 효과를 고려해야함을 보였다.

In order to remove rust and impurities from surface of raw SUS circular bar, peeling machine is used to make lustrous and clean surface of SUS circular bar. Drawing process system is used to manufacture SUS hexagonal bar. SUS hexagonal bar have been widely used to make hexagonal bolt/nut, adapter and fittings and so on. The purpose of this study is to investigate the stabilities for guide bar of clamp in drawing process system. As the results, the guide bar showed structural stability in cases of below load of 50 Ton and over hook radius of 3.0mm. Further as the thickness of guide bar hooking with jaw was increased, minimum safety factor was decreased.

SUS hexagonal bar, which is manufactured by drawing process of SUS circular bar, have been widely used to make various adapters and fittings. The purpose of this study is to investigate the characteristics and stability of variable roll unit including stand module. Stand module is essential part of variable roll unit. Structural analysis was performed to predict the stability of stand module using 3 loads (50, 75, 100 Ton), thus it may be of help to the manufacture of stand module. As the results, internal ring of bearing showed maximum equivalent stress, and moreover bearing, shaft and roller had to be preferentially considered in order to maintain its stability. In cases of 50 and 75 Ton, there were no problems for stabilities, respectively, on the other hand, problem for stability may occur in case of 100 Ton.

Although most of the automobile bodies are made of steel, the application of aluminum alloy sheet with high strength is under consideration for the development of environmentally friendly lightweight body for fuel economy improvement and carbon dioxide emission reduction. In the case of some inner plates, application of magnesium alloy sheet is examined. TRB plate has been studied mainly for weight reduction and rigidity reinforcement of steel plate parts. Recently, research on aluminum TRB rolled plate for light and environment friendly automobile application has been started, It is expected that the development of eco - friendly TRB rolling material made of light alloy will increase as the importance of light weight body for future energy efficiency increases. Therefore, in this study, we tried to obtain the technology to improve the quality of the product by pre - verifying the cooling performance of the hot forming process through the heat flow analysis and evaluating the cooling performance through the temperature distribution analysis. As a result, it was found that the temperature distribution through the flow velocity problem and the flow of the cooling channel can influence the quality of the final product through different heat distribution and cooling time depending on the shape of the mold and the product.

The objective of this study is to predict the formability of sheet metal for the bladder press. The static implicit finite element method is applied effectively to analyze bladder forming processes using AutoForm software. The material used for forming analysis is AL2024, and the thickness of the plate is 1.6mm, 1.8mm and 2.0mm. Forming force is shown by 101.92kN～87.22kN. The result from the simulation analysis was applied to the bladder press system.

Most of the structural forms in which ETFE film is used are the cushion(pneumatic membrane structures) and tension type(tensile membrane structures), which have been generally accepted to be the most efficient forms. Tensile membrane structures are pulled outward from the exterior to introduce initial stress. And such structures offer the advantage of a natural shape formed by tensile stress and eliminate the need for blast air. Recently, the number of tension type structures is increasing. However, there are problems of creep and relaxation of ETFE films under long-term stresses. In this paper, the stretch fabrication method is proposed for stretching the film into the plastic region during initial tensioning as a way to increase its strength. And its effectiveness is confirmed by investigating experimental and analytical test using ETFE films.

본 논문에서는 범용 유한요소프로그램 ANSYS와 ABAQUS를 이용하여 냉간성형강으로 조립한 조립기둥의 전체좌굴과 뒤틀림좌굴에 대한 비선형해석을 위한 모델링 기법을 소개한다. 냉간성형강의 경우 두께가 얇아서 국부좌굴 등 비선형거동을 보이기 때문에 좌굴에 대한 해석에 매우 섬세한 모델링이 필요하다. ANSYS의 내연적정적모델링에 의한 해석은 좌굴 극한점 부근에서 수렴의 문제를 발생하였지만, ABAQUS의 외연적동적모델링의 경우에는 좌굴 및 좌굴이후의 부재 거동에 대해서 안정적인 결과를 제공하였다. 또한 수치해석 결과는 좌굴실험을 통해 얻어진 축내력에 비해 높은 내력을 보여주고 있다. 이는 실험과정에서 발생하는 편심에 의한 영향으로서 수치해석에 의한 좌굴내력에 적정한 보정치의 적용이 필요하며 본논문에서는 기존 실험데이터와의 비교를 통해 0.88의 값을 제시한다.

The automotive industry in the research and development cost ratio accounted for high technology coefficient of specialization research and development budget. development and adoption of innovative technologies such as new materials technology, electronics technology, information and communications technology and new production systems is a source of competitive products. because permanent magnets without applying an external magnetic field in the BLDC motor drive system parts for EV can be supplied. it has been used in several areas. permanent magnet in the different kinds of motor parts materials is one of the key components. permanent magnet is a relatively fast rate of technological advances, changes in price is considered the fastest. in this paper, the BLDC motor parts produce by the core making method of casting method moulding analysis. moulding density was measured. As a result, the moulding density is measured 7.2~7.5g/cm2 results were excellent.

압출성형 ECC 패널을 활용한 철근콘크리트 복합 슬래브 구조에 대한 비선형 휨 해석 모델을 새롭게 제시하였다. ECC 패널은 직접인장시험 결과로부터 균열 이후에 고인성 인장거동을 하는 재료로 모델링하였다. 개발 모델을 기존 철근콘크리트 슬래브 및 ECC 패널 철근콘크리트 복합슬래브 실험체의 휨 실험결과와 비교하였다. 예측결과는 실험결과와 잘 일치하였으며, ECC 패널 적용 철근콘크리트 복합슬래브는 균열제어, 휨내력 및 휨변형능력 개선에 장점이 있는 것으로 판단되었다.

In the case of Inmold injection, it is a device which conducts injection and painting. In order to design it is important composition of devices to accurate feed of film and process of analysis. It used program of plastic injection flow analysis in order to a flow aspect of resin. It might be used shape crystallization of products, design of mold and process of feed device. In the case of inmold injection, film supply equipment is one of important device. 2-dimensional designs and 3-dimensional modelings are performed for its manufacturing. Specially 3-dimensional modeling data is used in structural strength analysis by finite element method. These background data is avail of manufacture of film supply equipment. Finally it is performed mold injection test and we got the satisfactory result.

본 논문은 횡하중을 받는 냉간성형 ㄷ 형강보의 응력해석에 관해 다루고 있다. 냉간형강 보에 가해지는 각 하중 레벨에서의 응력을 계산하여 국부좌굴과 횡좌굴을 고려하여 구조해석을 실시하였다. 해석모델은 박벽보의 기본이론에 의해 유도되었으며 1차원 보요소 유한요소해석을 통하여 수치해석을 하였다. 수치해석결과는 AISI 규준과 비교되었으며, 본 연구에서 제안된 해석모델이 냉간형강보의 처짐뿐 아니라 응력도 매우 정확히 예측함을 알 수 있었다.