• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 한국정밀공학회 2010년도 춘계학술대회 논문집
• /
• pp.1331-1332
• /
• 2010

• Journal of Korean Society of Steel Construction
• /
• 제23권4호
• /
• pp.483-491
• /
• 2011

The fabrication of steel structural members always involves welding process such as flux cored arc welding. Therefore, for the application of structural steels to cold regions, it is a prerequisite to clarify the service temperature of the welded joints in order to ensure the structural integrity of the welded parts. In this study, the Charpy impact test was conducted to evaluate the service temperature of structural steel weld. The Charpy impact test is a commercial quality control test for steels and other alloys used in the construction of metallic structures. The test allows the material properties for service conditions to be determined experimentally in a simple manner with a very low cost. Standard V-notch Charpy specimens were prepared and tested under dynamic loading condition. The service temperatures of the weld metal, HAZ (heat affected zone) and base metal were derived by the absorbed energy and the impact test requirements; thus the applicability of the structural steels to cold regions was discussed in detail.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 방전 플라즈마 유기절연재료 초전도 자성체연구회
• /
• pp.15-18
• /
• 2004

피뢰기에 뇌 또는 이상전압과 같은 정격이상의 고장전류가 유입되어 발생하게 되는 순간적인 열 충격과 내부압력 상승은 폭탄이 내부에서 터지는 것과 같은 엄청난 양의 충격에너지이다. 본 연구에 있어서 폴리머 피뢰기의 제조에 사용된 모듈용 브레이드 복합재료는 압력해소 및 폭발 비산하지 않도록 하는 기능을 수행하도록 설계되어있다. 기존의 폴리머 피뢰기에 적용된 복합재료보다 충격에너지를 흡수하는 구조물에 유리한 브레이드 복합재료를 피뢰기 모듈의 제조에 도입한 것은 매우 의미 있는 일이라 판단된다. 따라서 본 연구에서는 열경화성 브레이드 복합재료를 제조하기 위하여 프리폼을 먼저 제작한 다음 금형에 삽입한 후 진공상태에서 수지를 주입하여 경화시키는 RTM공법을 이용하였다. 본 연구의 목적은 브레이드 패턴 및 방압개소 설계 등의 기초적인 자료조사 및 실험을 통하여 폴리머 피뢰기의 폭발 비산을 방지할 수 있는 압력해소 성능을 위한 기초 자료를 확보하고자 하는 것이다. 브레이드 복합재료의 기본적인 경화거동을 등온 및 동적 DSC를 이용하여 고찰하였고, 기본적인 전기적 특성을 평가하였으며, 방압개소를 가진 폴리머 피뢰기 모듈의 고장전류시험시 예상되는 열 충격에 대한 성능을 검증하기 위하여 열팽창계수를 측정하였다.

• Elastomers and Composites
• /
• 제41권1호
• /
• pp.40-48
• /
• 2006

Mechanical systems with rubber parts have been used widely in industry fields. The evaluation of the physical characteristics of rubber is important in rubber application. Rubber material is useful to machine component for excellent shock absorbing characteristics. The impact characteristics of rubber were examined by experimental and finite element method. The impact test was conducted with a free-drop type impact tester. The ABAQUS/Explicit was used for finite element analysis. In the finite element analysis, elastic modulus of rubber using impact force was used as dynamic modulus, which are measured and predicted with dynamic property test and WLF model. The analysis result was coincided with the experimental results.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• 제30권3호
• /
• pp.241-248
• /
• 2006

Shoe cushioning systems are important to prevent body injuries. This study developed and evaluated a cushioning system to reduce impact force on the heel. The cushioning system suggested consist of a polyurethane pocket, which contains water and porous grains of open cell to dissipate the energy effectively. Load-displacement curves fer the shoe cushioning system were obtained from an instrumented testing machine and the results were compared with various pockets with air, water or grains. Mechanical testings showed that the pocket with 5g porous grain was the best for the cushioning system. This system can be applied to the design of various kind of sport shoes.

• Transactions of The Korea Fluid Power Systems Society
• /
• 제2권2호
• /
• pp.14-20
• /
• 2005

This study developed and evaluated a shoe cushioning system to reduce impact force patterns during running. The shoe cushioning system is composed with a poly urethane pocket, which contains water and porous grains to absorb the force against the weight inside the pocket. Load-displacement curves for the shoe cushioning system were obtained from an instrumented testing machine and the results were compared with various pockets that have air, water or grains. Mechanical testings showed that the pocket with 5 g particles was the best for the shoe cushioning system. This founding will be helpful to designing the shoe.

• Journal of the KSME
• /
• 제51권1호
• /
• pp.33-37
• /
• 2011

지금까지는 강도를 요구하는 구조재 신소재가 발달하였으나 21세기에는 기능성을 지닌 고기능신소재가 고부가가치를 창출하는 시대로 변화하고 있으며, 이중 한 가지인 충격흡수에너지와 소음, 진동 흡수능을 지닌 신소재 발포 금속의 활용성을 소개하고자 한다.

• Composites Research
• /
• 제13권4호
• /
• pp.75-82
• /
• 2000

A small diameter steel-ball impact experiment was performed to study the impact resistance of the surface of glass plates bonded with glass fabric/epoxy lamina. Five kinds of materials were used in this study: soda-lime glass plates, glass/epoxy lamina(one layer)-bonded and unbonded glass plates, glass/epoxy lamina(three layers)-bonded and unbonded glass plates. The range of impact velocity was 40 120m/s. The maximum stress and absorbed fracture energy were measured on the back surface of glass plates. With increasing impact velocity, various types of surface cracks such as ring, cone, radial and lateral cracks took place in the interior near the impacted site of glass plates. The cracks drastically decreased with glass/epoxy lamina coating. The surface fracture behavior could be evaluated using the maximum stress and the absorbed fracture energy.

• Journal of the Society of Naval Architects of Korea
• /
• 제29권2호
• /
• pp.92-102
• /
• 1992

Prediction of energy absorption for bow structure is important for a design of protective structures against collision. For the crushing behaviour of basic element of energy absorption, the plastic mechanism method is applied. The ship's crushing strength of bow section is obtained by summing the energy dissipated in all individual elements. The theoretical predictions are compared with experimental results for ship's bow models published with experimental results for ship's bow models published in the references, and it is observed that the present prediction method of crushing strength correlates well with the experimental results.

• Proceedings of the KSME Conference
• /
• 대한기계학회 2007년도 춘계학술대회A
• /
• pp.43-47
• /
• 2007

Based on experimental impact testing data, due to changing of velocity and mass of the impactor simultaneously under constant impact energy, crashworthiness of polyurethane foam has been observed. Dynamic tests were carried out in an instrumented impact-testing machine. Also, modified Sherwood-Frost model was proposed to investigate the crashworthy behaviour of rigid polyurethane foam under the condition of constant impact energy.