• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2008년도 춘계학술대회 논문집
• /
• pp.723-724
• /
• 2008

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2007년도 춘계학술대회 논문집
• /
• pp.511-512
• /
• 2007

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2011년도 추계학술대회 논문집
• /
• pp.637-638
• /
• 2011

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2007년도 춘계학술대회 논문집
• /
• pp.525-526
• /
• 2007

• 한국정밀공학회지
• /
• 제24권9호
• /
• pp.44-51
• /
• 2007

There are many methods to assemble various parts of a product, and one of them is the bolting system widely used in a industrial field due to the merits; easiness to obtain strong tightening force, simplicity of assemble or disassemble in order to repair, substitution or cleaning, and so on. But this bolting system needs attachments not to let a bolt loose and they are an important factor to cost a great deal. In this study, some equations are suggested and FE analyses are carried out to verify the cause of the bolt looseness occurring in the tightening process. And because the number of bolts in the bolting system has been decided by empirical know-how of designers in the field, safety rate in the plate type heat exchanger is often too high. Therefore the equations to decrease in quantity are suggested in consideration of the relationship between a critical shearing force acting on the screw and a normal force acting on the cooling plate by the working fluid.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
• /
• pp.793-796
• /
• 2008

교량 신축이음장치의 파손 유형은 주로 후타재(무수축 모르타르)와 관련된 부분에서 많이 발생된다. 또 다른 문제는 중차량 통과에 따른 충격과 진동하중으로 인해서 신축이음장치를 후타재에 고정하기 위해서 사용하는 앵커 풀림 현상이다. 본 연구에서는 무수축 모르타르의 파괴에 따른 신축이음 장치의 파손을 방지하기 위해 탄성콘크리트를 개발하였다. 개발된 탄성콘크리트와 현재 주로 사용하고 있는 무수축 모르타르의 인발성능을 비교하였다. 또한, 후타재와 신축이음장치를 일체화하여 후타재의 파손을 방지하고 신축이음장치를 쉽게 교체할 수 있는 앵커 시스템을 개발하였다.

• 한국정밀공학회지
• /
• 제32권6호
• /
• pp.523-528
• /
• 2015

As the sizes of mobile phones and watch phones decrease, the joining bolt for the products should also be decreased to a miniature size. However, the miniature-sized bolt has to support sufficient joining and anti-releasing torque to keep the product fastened. In this study, the thread shapes are designed to improve anti-releasing performance of bolts. Especially, when bolt materials is stronger than nut materials, the design of thread shapes is needed, like bolt for wood, to improve the fastening capability. Through the joining and releasing analyses of bolts, the thread shapes for SUS302 bolt and Mg alloy nut are newly designed. It was shown that the newly designed bolt has 20 % higher anti-releasing torque and 35% lower torque loosening slope compared to the standard bolt.

• 한국자동차공학회논문집
• /
• 제18권2호
• /
• pp.91-96
• /
• 2010

The combination of a bolt and nut is the element most widely used for connecting machines and structures. When a load is repetitively applied in the direction right angle to the bolt axis after the bolt and nut is fastened, the nut gradually becomes loose. To solve this problem, in this study, a new type of the loose-proof nut, called a lock nut, is developed. The lock nut is equipped with a spring, and the spring increases the axial force of the bolt. Then, the connection force between the bolt and nut is also augmented. Three dimensional finite element models for the bolt and spring are generated, and the change of the axial force of the bolt while the bolt is being inserted into the spring is analyzed using MSC/Marc, a commercial finite element program. Finally, the optimum shape of the spring is found according to the response surface analysis methodology. The optimization result is verified by comparing the variation of the axial force of the bolt when the bolt is inserted to the initial and optimized spring.

• 한국건축시공학회지
• /
• 제10권1호
• /
• pp.65-72
• /
• 2010

교량 신축이음장치의 파손 유형은 주로 후타재(무수축 모르타르)와 관련된 부분에서 많이 발생된다. 또 다른 문제는 중차량 통과에 따른 충격과 진동하중으로 인해서 신축이음장치를 후타재에 고정하기 위해서 사용하는 앵커 풀림 현상이다. 본 연구에서는 무수축 모르타르의 파괴에 따른 신축이음장치의 파손을 방지하기 위해 탄성콘크리트를 개발하였다. 개발된 탄성콘크리트와 현재 주로 사용하고 있는 무수축 모르타르의 인발성능을 비교하였다. 또한, 후타재와 신축이음장치를 일체화하여 후타재의 파손을 방지하고 신축이음장치를 쉽게 교체할 수 있는 앵커 시스템을 개발하였다.

• 한국정밀공학회지
• /
• 제18권1호
• /
• pp.129-138
• /
• 2001

This study examined the effects of the annealing heat treatments on the mechanical properties of the Invar(Fe-36%Ni Alloy) materials. Invar materials were annealed at various temperatures range 900~120$0^{\circ}C$ in vacuum(10-4Torr) and hydrogen atmospheres. And annealing conditions were changed by cooling rate and holding time at 110$0^{\circ}C$. The grain size of rolled Invar materials was very fine but those of annealed Invar materials at 900~120$0^{\circ}C$ in vacuum and hydrogen atmosphere increased with increasing annealing temperature. The micro-vickers hardness values of annealed Invar materials were decreased about 15% that of the rolled Invar materials, regardless of the various of annealing temperatures, atmosphere(vacuum, hydrogen) and annealing conditions. The tensile strength and yield strength of annealed Invar materials at 900~120$0^{\circ}C$ in vacuum and hydrogen atmosphere were decreased 10.0~14.4% and 34.6~39.1% those of the rolled Invar materials, respectively. The strength ratio(tensile strength/ yield strength) of annealed Invar materials was improved to 1.7~1.8 from the value of 1.2~1.3 of rolled Invar materials. The degree of spring back of annealed Invar materials was about 50% of the rolled Invar materials, regardless of the various of annealing temperatures, atmosphere(vacuum, hydrogen) and annealing conditions.