The automotive industry continuously strives to enhance safety for both drivers and passengers through technological advancements. Car side impacts have the potential to significant risks to passengers, So the automotive industry has proposed various technological solutions. As part of these efforts, the development of side impact beams, which are affixed to the inner frame of vehicle side doors to absorb and dissipate collision energy, has been a safety enhancement. Conventional side impact beams are manufactured using hot-rolled steel sheets and have a pipe-like configuration. However, these impact beams are fixed to the vehicle's chassis, which directly transfers the energy generated during a collision to the chassis frame. This paper aims to address this issue by proposing the development and optimization of vehicle door impact beams using a dual-beam structure and fastening method, utilizing shear bolts. Moreover, the focus is on optimizing the cross-sectional shape of the dual-beam impact structure. The evaluation criterion for optimization is based on the second moment of area of the cross-section. To validate these improvements, Static experiments were conducted, comparing the proposed dual-beam structure with the traditional impact beam. This research is expected to serve as a guideline for enhancing vehicle safety through design directions and validation methods.

The purpose of this study was to develop a side protection device for school buses for children. In the case of the door side impact beam, it plays a very important role because it protects passengers from external collisions. However, in the case of a school bus for children, the space between the door and the door trim is very narrow, unlike a general passenger car. So, as an alternative to this, we are trying to develop Rub Rail, which is compulsory for children's school buses in the United States. Based on the results of structural analysis according to the cross-sectional shape of the rub rail, we want to find out the appropriate shape of the rub rail.

In this study, we compare and analyze stress and vertical deflectional displacement according to cross sectional shape changes of the beam using finite element analysis. The 11,000mm long horizontal beam showed stress differences depending on the cross-sectional variation, with stress differences of up to 200MPa and at least 149MPa. The deflection at the end of the beam also differed by up to 586 mm and at least 208mm. The weight change applied according to the cross-sectional shape of the steel horizontal beam was up to 235kgf, at least 144kgf, and showed the best stress and deflection characteristics in the cross sectional shape with a weight of 185kgf. This allowed us to improve structural safety through sectional shape optimization despite the weight increase.

A basic metal deposition experiment for manufacturing aluminum parts was performed using WAAM (Wire arc additive manufacturing), and the cross-sectional shape of the laminate according to nine deposition conditions. The effect of heat input was analyzed for the bead shape according to the deposition conditions, and the deposition efficiency was calculated by analyzing the cross-sectional shape of thin-wall parts made of aluminum. The amount of heat input was used in the experiment from about 2.7 kJ/cm to 4.5 kJ/cm, and the closer the heat input was to 4.5kJ/cm, the higher the deposition efficiency was. The maximum lamination efficiency obtained through this study reached 76%.

This study investigates the optimization of sectional shape with two dimensions on the rubber gasket of electric vehicle battery in order to maintain the airtightness and watertightness. For the section optimization, the shape of protruding section was analyzed as design variables and the design point was composed by the design of experiment(DOE) for the selected protruding shape. The uniaxial tensile test was carried out for the analysis of rubber gasket and five parameters of Mooney-Rivlin hyperelastic model were derived from the test data in order to construct the strain energy function for nonlinear behavior. The rubber gasket compression analysis was performed by using ANSYS of a commercial software and the performance of optimal shape was verified by performing the tests of watertightness and airtightness on the 3D rubber gasket with the derived section.

In this paper, we investigated the change of sectional shape according to the tension when the reed wire was rolled. When rolling is performed, the tension acting on the reed wire acts in the opposite direction of the rolling progress and prevents twisting or bending phenomenon. The shape of the cross section was changed according to the tension acting on the reed wire, and the reed wire was rolled by continuously rolling the flat rolled wire and the tension was applied to the reed wire to control the simulation. As a result of the experiment, it was confirmed that the dimensions of the thickness and width after rolling can be adjusted through the tension acting on the lead wire. It was also confirmed that as the tension increased, the length of the lead wire increased and the residual stress increased.

The curved beam has a complicated behavior compared to a straight beam due to torsional and warping. Therefor, in this study, eigenvalue analysis was performed for curved beam with different shape(I-shape, T-shape, box-shape) corresponding to the same value of the moment of inertia. As a result the curved beam with box-shape section had a larger natural frequency value than the other curved beam. Also, the dynamic analysis results showed that the largest result was obtained at 826.18MPa in the T-shape curved beam when the gyeongju earthquake was applied.

In the present study, FE analysis was performed for characterising structural strength of a seat frame w.r.t. varying sectional shapes as well as different materials of the seat back frame based on the FMVSS 207 regulation in order to obtain the design outline of a lightweight seat frane structure. Four types of materials, i.e., SAPH440, Al7021, Al6082 and carbon/epoxy composites were applied to the seat back frame type beams and their bending behaviours were compared by three point bending FE analysis. Consequently, the lightweight structure of seat back frame with the equivalent strength characteristics of conventional frame was suggested.

In this paper, a local deformation effect in thin-walled box beams is investigated via a finite element modal analysis. The analysis is carried out for single-cell and multi-cell box beam configurations. The single-cell box beam with and without a neck, which mimics a simple wind-turbine blade, is analyzed first. The results obtained by shell elements are compared to those of one-dimensional(1D) beam elements. It is observed that the wall thickness plays a crucial role in the natural frequencies of the beam. The 1D beam analysis deviates from the shell analysis when the wall thickness is either thin or thick. The shell modes(local deformations) are dominant as it becomes thin, whereas the shear deformation effects are significant as it does thick. The analysis is extended to the single-cell box beam with a neck, in which the shell modes are confined to near the neck. Finally the multi-cell box beam with a taper, which is quite similar to real wind-turbine blade configuration, is considered to investigate the local deformation effect. The results reveal that the 1D beam analysis cannot match with the shell analysis due to the local deformation, especially for the lagwise frequencies. There are approximately 5∼7% errors even if the number of segments is increased.

본 논문에서는 Co-Rotational plane beam transient analysis EDISON program(CR-보)를 이용한 에어포일 단면형상 변화 에 따른 진동특성 연구를 수행하였다. Co-Rotational 평면 보 해석은 대 회전과 작은 변형률을 갖는 보 해석에 적합하다. 항 공기의 날개를 외팔보로 가정하여, VABS를 통한 단면해석과 Fourier 변환을 통해 각 단면형상 변화에 따른 에어포일의 고 유진동수를 비교하였다. VABS를 사용하여 단면의 형상과 재료의 적층 정보를 고려한 단면에서의 유한요소 해석을 수행하 였다. 에어포일의 재질, spar 유무, 단일 등방성 재료·복합재료, 에어포일 최대두께의 변화에 따라 에어포일의 끝단 진폭과 고유진동수가 변화함을 확인할 수 있었다. 이를 바탕으로 에어포일 고유진동수 변화는 2차 관성모멘트/단면적, 밀도, 영률의 변화에 상당한 영향을 받음을 알 수 있었다.

The volume of fluid (VOF) method is applied to study the effects of the gas channel cross-section shape on the removal characteristics of a water slug in a trapezoidal PEMFC gas channel. Two different open angles 50 and 60 degrees are selected to investigate the effect of cross-section shape on the behavior of a liquid water slug. In comparison to the 50 degrees case, the water slug is removed slightly faster for the 60 degrees case.

The aim of this study was to use a 3D human body scanner to analyze the cross section of different body parts when a girdle is worn. Two types of girdles were selected as experimental garments: a standard type girdle (Garment A) and a high-waist type girdle (Garment B). Their sizes were 88 (S) and 94 (M). Ten female subjects in their twenties who wear girdles sizes 88 (S) and 94 (M) participated the experiment. Their bodies were scanned three times with the 3D human body scanner, before and after wearing experimental girdles. The data were collected by overlapping the cross sections of the 3D scanned body shape data. The space length was measured from the overlapped cross sections. The results show that human body silhouette are changed after wearing the compression type garments and the amount and place of the body change is different by style of garments. First, the waist girth shape became rounder. Second, there was a definite difference in space amount at abdomen girth between two types of girdle. The abdomen area was pushed toward the front after wearing the standard type girdle (A). The high-waist type girdle (B) pushed abdomen area toward the back. Third, there was clear difference at the hip area after wearing two types of girdle. The hip area pushed toward the front with the standard type girdle (A) and pushed toward the back with the high-waist type girdle (B).

The circular hollow section is usually used for member of main frame to carry the external load in single layer lattice dome. But, the H-shaped section may be used for member of main frame since it is convenient for attaching roof panels. Single layer lattice domes have various buckling characteristics, such as the overall buckling, the member buckling, and nodal buckling. The purpose of this study is to compare buckling characteristics of single-layer lattice domes in which the H-shaped steel section as the existing domestically-produced structural steel is used as main frames to those of domes in which a circular hollow section is used as main frames.

본 연구에서는 하부박스형상을 변화시킨 단일 박스거더단면에 대하여 변장비 1:51:10의 범위에서 풍동실험을 통하여 동적응답특성을 고찰하였다. 거더의 단면형상변화는 직사각형 1종류와 사다리꼴 단면 2종류를 선정하였다. 실험결과를 정리하면, 와류진동의 경우, 변장비 1:5에서는 전반적으로 직사각형거더에 비하여 사다리꼴 거더단면의 연직 및 비틀림 최대진폭이 감소하는 경향을 알 수 있으며 1:7.5의 경우는 미소하나마 직사각형단면의 와류진동응답이 사다리꼴 단면에 비하여 안정적인 응답을 보였다. 갤로핑은 변장비 1:5단면중에서 사다리꼴 단면(B050-1단면)의 (+)영각 범위에서만 발생하였고 그 이외의 모든 단면에서는 발생하지 않았다. 비틀림 플러터는 1:5 및 1:10단면 의 (+)영각범위에서 발생하였고 단면형상변화에 따른 한계풍속의 변화는 두드러지지 않았다. 또, 변장비 증가에 따라 와류진동의 발생은 (+)영각범위로 제한되고 최대진폭도 감소하는 추세를 보였으며 발산진동의 한계풍속도 증가하는 경향을 보였다. 하부박스거더의 형상변화에 따른 응답변화는 변장비가 증가할수록 그 차이가 작아지는 경향을 보였다.

Pultruded FRP (Pultruded Fiber Reinforced Polymeric Plastic, PFRP) members have many advantages such as high strength and stiffness, high corrosion resistance, light weight, etc. However, it has relatively low modulus of elasticity and also cross-section of the structural shapes is composed of thin plate components. Therefore, global buckling, local buckling, and post-buckling strengths should be considered in the design of compression members. In the structural steel design following AISC/LRFD, this effect, in addition to the buckling strength, is incorporated with a form factor. In this study, referring to AISC/LRFD, form factor for the design of I-shape and Box-shape PFRP members under compression has been suggested and discussed through the analytical study.

본 연구는 도로안전 시설물의 풍하중에 의한 손상발생 사례를 토대로 현행 도로안전 시설물의 구조적 휨 성능을 평가하고 이에 대한 부재별 휨 성능개선을 위한 연구이다. 본 연구의 대상구조물로는 대표적인 도로안전시설물이며 풍하중에 대한 선행 피해사례가 밝혀진 방음벽 지주프레임을 대상으로 고려하였으며 이들 지주프레임의 휨 구조성능 및 형상설계에 대한 평가를 우선적으로 수행하였다. 본 연구평가 결과에서 나타난 현행 보강재의 구조적 성능을 토대로 중량 대비 구조적 강성이 우수한 유리섬유 강화플라스틱 (GFRP)을 활용하여 다양한 보강 형태에 따른 성능개선방법을 해석 및 실험적 연구를 통하여 수행하였다. 그 결과 효율적 성능개선을 위한 GFRP 적용방법의 경우 구조적, 시공적 측면에서 효율적인 것으로 평가되었고 자체적인 형상단면 최적설계를 통한 개선방법도 성능보강에 효과적인 것으로 해석적으로 평가되었다. 본 연구에서 적용된 GFRP 단면보강 및 최적형상설계 연구는 향후 노후 도로안전 시설물의 풍하중 또는 태풍으로 인한 피해예방을 위한 기초자료로서 효율적으로 활용될 수 있을 것으로 판단된다.

본 연구는 박스거더단면을 대상으로 정적공기력특성에 미치는 단면형상의 영향을 파악하기 위하여 변장비 B/ D=2.5~15 범위에서 6종류의 기본단면을 채택하고 하부거더의 개수 및 브래킷 길이를 변화시킨 총 47개 단면에 대하여 영 각 -8o~+8o 범위에서 풍동실험을 통하여 정적공기력을 측정하였다. 그 결과를 요약하면, 전연박리류의 재부착여부에 따라 정적공기력계수는 확연한 차이를 나타냈으며, 브래킷부의 유무에 따라서도 공기력계수의 변화특성이 달라졌으며, 하부거 더수의 변화는 공기력계수의 변화에 크게 영향을 미치지 않았다. 또, 영각 -5o~+5o 범위에서 최대 항력계수는 CD=1.5 정도로 현행 기준치에 약간 밑도는 값으로 나타났으나, 양력계수는 최대값이 CL=0.95, 최소값은 -0.6 정도로 무시할 만큼 작은 값은 아니므로 향후 설계기준개정시 반영되어야 될 것으로 판단된다. 모멘트계수은 최대값 0.05, 최소값은 -0.29로서의 타 계수에 비하여 미소한 값으로 나타났다.

본 연구에서는 플레이트거더단면의 정적공기력특성에 미치는 단면형상의 영향을 파악하기 위하여 변장비 B/ D=2.5~15범위에서 6종류의 기본단면을 채택하고 주거더의 수와 브래킷 길이를 변화시킨 총 36개 단면에 대하여 영각 -8o~ +8o 범위에서 풍동실험을 통하여 정적공기력을 측정하였다. 그 결과를 요약하면, 전연박리류의 재부착여부에 따라 정적공기력계수는 확연한 차이를 나타냈으며, 브래킷부의 유무에 따라서도 공기력계수의 변화특성이 달라졌으며, 거 더수의 변화는 공기력계수의 변화에 크게 영향을 미치지 않았다. 또, 영각 -5o ~ +5o 범위에서 최대 항력계수는 변장비가 8이상에서는 현행 기준의 항력계수보다 월등히 크게 나타났으며, 양력계수는 최대값이 CL=1, 최소값은 -0.7 정도였고, 모멘트계수의 최대값은 0.1, 최소값은 -0.18이였다. 이를 근거로 항력계수 및 양력계수에 대한 제안식을 도출하였다. 변장비에 따른 양력계수의 기울기 dCL/dα는 변장비 7.5까지는 증가하다가 그 이상이 되면 일정한 값을 가지고 브래킷의 길이가 길어질수록 작아지는 경향을 나타냈으며, 모멘트계수의 기울기는 변장비 5까지는 증가하다가 그 이후부터는 감소하는 패턴을 가지고 있었다.