• 한국자동차공학회논문집
• /
• 제16권2호
• /
• pp.114-119
• /
• 2008

The modern automotive industry develops innovative vehicle designs to meet increasing stability of car and performance demands of their customers. The improvement of frame rigidity by the structural foam is thought to be an effective means to improve the performance because of high applicability and minimum weight. The object of this paper is to examine the use of structural foam in a hat section as an optimum reinforcing means, to compare the reinforcing performance of structural foam versus a plastic reinforcement. The result of this paper indicated that reinforcing efficiencies are achieved by structural foam and plastic reinforcement shape.

• 한국자동차공학회논문집
• /
• 제14권2호
• /
• pp.92-99
• /
• 2006

Design capability for high safety vehicle with light weight is crucial to enhancing competitive power in vehicle market. The structural foam can contribute to restraining section distortion in body members undergoing bending collapse at vehicle crash. In this study, first, the validation of analysis model including structural foam model for simulating fracture behavior was discussed, and the bending collapse characteristics of five representative section types were analyzed and compared. Next, with changing the laminate foam shape, load carrying capability and absorbed energy were observed. The results suggests a design strategy of body members filled with laminate foam, leading to effectively elevating bending collapse characteristics with weight increase in the minimum.

• 한국자동차공학회논문집
• /
• 제15권2호
• /
• pp.41-49
• /
• 2007

More diversified and strengthened safety regulations require higher safety vehicle with less weight. The structural foam can play a role for restraining section distortion of main body members undergoing bending collapse at vehicle crash. In this study, using structural foam modeling technology, validated in previous work, the bending collapse characteristics were evaluated for two types of circular and actual vehicle body frame sections. With changing the foam filling method, outer panel thickness and section shape, load carrying capability and absorbed energy were observed. The results indicate valuable design strategy for effectively elevating bending collapse performance of body members with foam filled.

• 한국분말재료학회지
• /
• 제27권1호
• /
• pp.37-43
• /
• 2020

The Fe-22wt.%Cr-6wt.%Al foams were fabricated via the powder alloying process in this study. The structural characteristics, microstructure, and mechanical properties of Fe-Cr-Al foams with different average pore sizes were investigated. Result of the structural analysis shows that the average pore sizes were measured as 474 ㎛ (450 foam) and 1220 ㎛ (1200 foam). Regardless of the pore size, Fe-Cr-Al foams had a Weaire-Phelan bubble structure, and α-ferrite was the major constituent phase. Tensile and compressive tests were conducted with an initial strain rate of 10^-3/s. Tensile yield strengths were 3.4 MPa (450 foam) and 1.4 MPa (1200 foam). Note that the total elongation of 1200 foam was higher than that of 450 foam. Furthermore, their compressive yield strengths were 2.5 MPa (450 foam) and 1.1 MPa (1200 foam), respectively. Different compressive deformation behaviors according to the pore sizes of the Fe-Cr-Al foams were characterized: strain hardening for the 450 foam and constant flow stress after a slight stress drop for the 1200 foam. The effect of structural characteristics on the mechanical properties was also discussed.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2006년도 정기 학술대회 논문집
• /
• pp.906-913
• /
• 2006

The failure mechanism of a hollow bridge deck which is made of glass fiber reinforced polymer(GFRP) is investigated using both experiments and analysis. While the load-displacement behavior of the deck in the transverse direction shows a strong nonlinearity even in its initial response with relatively small magnitude of loads. In order to imporve the structural behavior of the deck in the transverse direction, we suggested that the empty space of the bridge deck is filled with a foam and investigated experimentally the static behavior of the orthotropic bridge deck which is made from GFRP and polyurethane foam. It is found that although the elastic modulus of the foam compared to that of the GFRP is about the order of $10^{-3}$, the structural behaviors in the weak axis such as nominal strength, stiffness, etc. are greatly improved. Owing to the low mass density of the foam used in this study, the bridge deck is still light enough with the improved structural properties.

• International Journal of Automotive Technology
• /
• 제4권3호
• /
• pp.141-147
• /
• 2003

For improving high-safety, convenience, and ride comfort, the automotive design suffers from radical increase of the weight, the recycling-related rules, regulations on the waste gas, and environmental protection of the resources. Among them, it is well known that the weight increase is the most critical. Thus, in order to minimize the weight of the body-in-white that takes up 20-30% of the whole weight of the automobile, most automotive manufacturers have attempted to develop the aluminum intensive body-in-white using aluminum space frames. In this research, the crush test and simulation for aluminum extrusions are performed to evaluate the collapse characteristics of that light weighted material. Also. the same test and simulation was done for aluminum extrusions filled with structural foam. Then, these results are analyzed and compared. From these studies, the effectiveness of structural foam is evaluated in improving automotive crashworthiness. Finally, the design strategy and guideline of the structural form are suggested in order to improve the crashworthiness for aluminum space frame in the vehicle.

• Advances in Computational Design
• /
• 제4권3호
• /
• pp.251-272
• /
• 2019

This study performed lateral load testing on seventeen wood wall frames in two sections. Section one included eight tests studying structural foam sheathing of shear walls subjected to monotonic loads following the ASTM E564 test method. In this section, the wood frame was sheathed with four different types of structural foam sheathing on one side and gypsum wallboard (GWB) on the opposite side of the wall frame, with Simpson HDQ8 hold down anchors at the terminal studs. Section two included nine tests studying wall constructed with oriented strand board (OSB) only on one side of the wall frame subjected to gradually applied monotonic loads. Three of the OSB walls were tied to the baseplate with Simpson LSTA 9 tie on each stud. From the test results for Section one; the monotonic tests showed an 11 to 27 percent reduction in capacity from the published design values and for Section two; doubling baseplates, reducing anchor bolt spacing, using bearing plate washers and LSTA 9 ties effectively improved the OSB wall capacity. In comparison of sections one and two, it is expected the walls with structural foam sheathing without hold downs and GWB have a lower wall capacity as hold down and GWB improved the capacity.

• Advanced Composite Materials
• /
• 제17권4호
• /
• pp.343-358
• /
• 2008

This present study provides the structural design and analysis of main wing, horizontal tail and control surface of a small scale WIG (Wing-in-Ground Effect) craft which has been developed as a future high speed maritime transportation system of Korea. Weight saving as well as structural stability could be achieved by using the skin.spar.foam sandwich and carbon/epoxy composite material. Through sequential design modifications and numerical structural analysis using commercial FEM code PATRAN/NASTRAN, the final design structural features to meet the final design goal such as the system target weight, structural safety and stability were obtained. In addition, joint structures such as insert bolts for joining the wing with the fuselage and lugs for joining the control surface to the wing were designed by considering easy assembling as well as more than 20 years service life.

• International Journal of Aerospace System Engineering
• /
• 제10권2호
• /
• pp.1-4
• /
• 2023

Even though the recent development trend of wind turbine systems has been focused on larger MW Classes, the small-scale wind turbine system has been continuously developed because it has some advantages due to easy personnel establishment and use with low cost and energy saving effect. This work is to propose a specific structural design and analysis procedure for development of a low noise 500W class small wind turbine system which will be applicable to relatively low wind speed region like Korea. The proposed structural feature has a skin-spar-foam sandwich composite structure with the E-glass/Epoxy face sheets and the Urethane foam core for lightness, structural stability, low manufacturing cost and easy manufacturing process. Moreover this type of structure has good behaviors for reduction of vibration and noise. Structural analysis including load cases, stress, deformation, buckling and vibration was performed using the Finite Element Method. In order to evaluate the designed blade structure the structural tests were done, and their test results were compared with the estimated results.

• 비파괴검사학회지
• /
• 제36권6호
• /
• pp.474-482
• /
• 2016

가벼운 다공성 구조재로서 널리 사용되는 캘빈 폼(foam) 재료의 탄성특성을 초음파를 이용하여 조사하였다. 캘빈 폼의 구조는 tetrakaidecahedron의 단위 셀(unit cell)이 규칙적으로 3차원 배열된 구조를 갖고 있는데 본 연구에서는 SoildWorks 프로그램에서 캘빈 단위 셀을 설계하고 ABS 플라스틱 재료를 이용하여 3차원 프린터로 제작한 후 초음파시험을 수행하였다. 캘빈 구조체는 기공이 많은 재료이기 때문에 초음파가 투과할 수 없어서 빈 공간을 모두 파라핀 왁스로 충진하여 초음파가 투과할 수 있도록 하였다. 파라핀을 충진한 캘빈 구조체는 초음파의 비행시간(TOF)을 이용하여 초음파 속도를 계산한 후, 이 복합 구조체에 대한 탄성 구조 모델을 기반으로 캘빈 구조체만의 탄성계수를 계산하였다. 측정된 캘빈 구조체의 탄성계수 값은 모재(ABS 플라스틱) 탄성계수의 약 3.4%가 되는 것으로 나타났는데 이 평가 결과는 선행된 연구 결과들에서 나타난 실험값이나 이론 해석 결과와 잘 일치하는 것을 확인할 수 있었다.