In order to respond to environmental pollution, developed countries, including Korea, have begun to conduct research to utilize hydrogen energy. For mass transfer of hydrogen energy, storage as liquid hydrogen is advantageous, and in this case, the volume can be reduced to 1/800. As such, the transportation technology of liquefied hydrogen for ships is expected to be needed in the near future, but there is no commercialized method yet. This study is a study on the technology to test the performance of the components constituting the membrane type storage container in a cryogenic environment as a preparation for the above. It is a study to find a way to respond by analyzing in advance the problems that may occur during the shear test of adhesives. Through this study, the limitations of ISO4587 were analyzed, and in order to cope with this, the specimen was supplemented so that fracture occurred in the adhesive, not the adhesive gripper, by using stainless steel, a low-temperature steel, to reinforce the thickness. Based on this, shear evaluation was performed under conditions lowered to minus 243℃, and it was confirmed that the breaking strength was higher at cryogenic temperatures.
Conversion to modern hydrogen energy is required, and research on liquefied hydrogen cargo containment systems is needed for large-capacity transport and storage. In this study, changes in the mechanical properties of the adhesive required for storage and transport in liquid hydrogen were confirmed. The lap shear test was performed by realizing cryogenic conditions in a small chamber using liquid nitrogen and liquid helium. There was an increase of 11.0% in the -180℃ condition compared to room temperature, and an increase of 1.8% in the -230℃ condition compared to the -180℃ condition was confirmed. In the case of shear strain, it is known that it decreases as the temperature goes down. As a result of the experiment, it was confirmed that the value at room temperature and the value at -180℃ reduced the shear strain by 5.0%, and -230˚ compared to the -180℃ condition. An increase of 1.5% was confirmed in the C condition. In the case of the specimen tested at -230℃, the deformation in the gripper part was larger than in other tests, and it is judged that the maximum shear strength and shear strain were affected. In addition, in this study, there is a limitation in the experiment at -230°C rather than 253°C, which is the boiling point of hydrogen
알루미늄 폼을 볼트나 너트를 이용하여 체결한다면 경량성이 감소되므로 접착제로 접합하는 것이 가 장 효율적이다. 이런 알루미늄 폼 접착 구조물에 대한 충격 피로 특성과 접착 합면에 대한 파괴인성 연 구는 매우 부족하며 또한 중요하다. 이에 따라 본 연구에서는 알루미늄 폼으로 만들어진 DCB모델을 접 착제로 접합한 후 두께를 변수로 하여 25mm 부터 45mm까지 10mm차이를 두어 실험과 컴퓨터 시뮬레 이션을 통하여 수행하였다. 실험은 MTS사의 인장 시험기를 사용하여 강제 변위 100mm를 주어 변위에 따른 전단력을 알아보았고, 실험과 똑같은 조건하에 ANSYS를 이용하여 유한요소해석을 수행하였다. 실험과 유한요소해석 값을 비교하여 접착제로 접합된 알루미늄 폼 구조물의 접착 합면에 대한 파괴인성을 고찰하였다.
Aluminum foam has many superb properties such as light weight, impact absorption and thermal resistance by comparing with original metallic materials. Composite materials made of aluminum foam have used at various fields as automotive bumper, shock absorption, vessel and aircraft. But it is inefficient to join aluminum foam with bolt and nut because of the property of light weight. In this study, this approach is investigated by joining aluminum foam with adhesive. Impact fatigue and failure toughness at the commissure of adhesive structure are studied by simulation analysis. This study aims to investigate the shear strength evaluation at shear mode of adhesively bonded joint with double cantilever beam(DCB) made of aluminum foam.
By attaching the adhesive retrofit material using wire and nylon to masonry walls, the changes in the shear strength of the walls were examined through experiments. In the experiment results, when the adhesion of the adhesive retrofit material was secured, the shear strength and the yield displacement ratio of the masonry walls were largely improved, and the falling of the walls did not happen, which has verified the retrofitting effect of the adhesive retrofit material.
탄소섬유시트의 부착성능을 조사하는 방법으로써 중앙을 절단한 보 공시체를 이용한 휨 거동 형식의 시험기를 개발하여, 콘크리트의 압축강도를 변수로 정적 재하 실험을 실시하였다. 탄소섬유시트의 파단의 결과를 이용하여 이 시험기의 검증과 함께 전단부착강도의 산출식을 도출하려고 노력 하였다. 그 결과, 첫 번째로 새로운 형식의 시험기에 의한 부착강도시험의 타당성이 증명되었다. 두 번째는 CFS 표면 변형률의 결과로부터 구해진 전단부착강도는 2종류의 경향이 있음이 발견되었다. 그 데이터 중에서 비교적 안정성이 높은 전단부착강도의 평균치는 3.41MPa, 하한치는 2.11MPa이었다. 이번 실험에서는 콘크리트의 강도가 전단부착강도에 미치는 특별한 영향을 볼 수 없었다.