V-type coupling, which is often applied to wastegate-turbochargers(WGT), is a mechanical fastener. Its radial forces generated from the bolt pretension load colse contact with each other to the axial direction for turbine housing and center housing rotating assembly(CHRA). In addition, the torsional stiffness between two bodies should be sufficiently secured to minimize the linkage angle change from the EWGA to the valve spindle. Therefore, in this study, the torsional stiffnesses according to the effects of positioning pins and friction coefficient, and the bolt pretension loads were calculated for V-coupling turbocharger. As a result, it can be seen that the torsional stiffness of the coupling according to the number of position pins is very small. And, when the friction coefficient and the axial force of the bolt are large, the torsional stiffness is greatly increased, and gradually decreasing when the bolt load of the coupling is about 6,000 N or more.

The clamping of torque shear high strength bolt is induced when the pin-tail is broken. However the tension forces induced shank of the bolt do not be known by now. This study focused to develop a quantitative method to identify the induced tension by analyzing the electric energy of which electric torque wrench (rpm 20) was applied to high strength bolt at the break of pin tail. Based on this co-relation between tension and accumulated current, the regressive analysis was derived. The error rate between tension and accumulated current was 5.06%.

The clamping of torque shear high strength bolt is induced when the pin-tail is broken. However the tension forces induced shank of the bolt do not be known by now. This study focused to develop a quantitative method to identify the induced tension by analyzing the electric energy of which electric torque wrench was applied to high strength bolt at the break of pin tail. Based on this co-relation between tension and accumulated current, the regressive analysis was derived. The error rate between tension and accumulated current was 2.24%.

Torque control method and turn of nut method are specified as clamping method of high strength bolts in the steel construction specifications. Quality control of torque coefficient is essential activity because torque control method, which is presently adopted as clamping method in domestic construction sites, is affected by variation of torque coefficient. The clamping of torque shear bolt is based on KS B 2819. It was misunderstood that the tension force of the TS bolt was induced generally at the break of pin-tail specified. However, the clamping forces on slip critical connections do not often meet the intended tension, as it considerably varies due to torque coefficient dependent on the environmental factors and temperature variables despite the break of the pin tail.This study was focused to evaluate the effect of environmental factors and errors of installing bolts during tightening high strength bolts. The environmental parameters were composed of 'wet' condition, 'rust' condition, 'only exposure to air' condition. And the manufacture of trial product was planned to identify the induced force into the bolts. The algorithm for a trial product was composed of the relation between electricity energy taken from torque shear wrench and tension force from hydraulic tension meter.

고력볼트의 초기 체결력은 미끄럼표면조건에 따라, 일정시간이 경과될 때까지, 축력저하가 발생한다. 이 연구는 미 끄럼접합부 표면에 도장이 되어있는 경우, 도장의 크리프현상에 따른 축력저하에 관한 예측 모델을 찾는 것이다. 이 실험연구 범위는 무기질 아연 프라이머로 도포된 볼트접합부의 장기축력저하에 한정한다. 실험에 적용된 볼트종 류는 다크로 도포된 토크쉬어 볼트이다. 대상 표면의 도막 두께는 각각 96, 168, 226㎛ 이었다. 도막두께가 증가될 수록, 초기 체결이후 축력이완율은 도막의 크리프 때문에 10%에서 18%로 증가되었다. 장기축력예측을 위한 정량적 인 모델은 도막두께에 따른 크리프 스트레인과 경과된 시간사이에 회귀분석 결과로 얻어진다. 이 실험연구를 통해 미끄럼표면 도막의 크리프 거동특성을 알 수 있다면, 일정시간 경과후 고력볼트 체결력은 초기 체결력으로부터 구 할 수 있다. 본 실험결과를 근거로 각 도막두께에 대한 장기축력이완이후의 고력볼트 체결력에 관한 정량적인 수식 을 제안하였다.

The initial clamping forces of the high strength bolts depending on the different faying surface conditions drop within 1,000 hours regardless of loading any other external force or loosening of the nut. This study focused on the mathematical model for relaxation confined to creep on coated faying surface after initial clamping. The quantitative equation for estimating long term relaxation was derived from nonlinear regression analysis for relation between the creep strain of coated surface and the elapsed time.

현수교 주 케이블은 케이블 밴드의 볼트 축력에 대한 정기적인 유지 관리가 매우 중요하다. 현수교 케이블 밴드의 볼트 축력은 시간이 경과함에 따라 케이블 소선의 크리프 현상, 볼트의 릴렉세이션, 하중 변동, 케이블 소선의 재배열 등으로 인해 축력 감소 현상이 발생하게 된다. 본 연구에서는 국내 현수 교량(SR대교)의 케이블 밴드가 시간이 경과하면서 발생하는 축력 감소 현상에 대해 그 원인 및 감소량 등에 대한 현장 측정 및 이론적 검토, 안전율 검토, 장기적인 이력 관리 등을 수행하였다. 그 결과, 케이블 밴드 볼트 축력 감소는 주 케이블 소선에 사용된 아연 도금층의 소성 변형에 크게 영향받는 것을 확인하였으며, 이에 대한 이론적 체계 및 장기 이력 관리에 대한 적용성을 확립하였다.

High-strength bolt has high stiffness and fatigue strength. At this time, initial axial force is one of main factor to affect the strength and deformation behavior of connection. Therefore, the objective of this study is to investigate reduction of initial axial force in high-strength bolt under shear fatigue.

The purpose of this study was to analyze the reduction of clamping force of TS (torque shear) bolted connection under fatigue loading. Generally, TS bolt has been totally tightened by torque shear wrench. However the plant structures experienced various fatigue loadings that makes reduction of clamping force of TS bolt. Therefore, this study conducted to the fatigue load test.

This study on the maintenance of axial force of the cable band bolts in suspension bridge. The axial force on the cable band is reduced as suspension bridge of increases service period. In is a summary of the field measurement results and review of cause.

This study dealt with the change in the clamping force of bolt in the friction joint depending on the sectional damage of bolt. Based on the study of the clamping axial force of bolt and sectional damage, clamping force of bolt was affected by sectional damage of bolt head. Thus, relationship between clamping axial force of bolt and corrosion damage of bolt should be considered for maintenance of steel structures.

토크쉬어볼트의 토크계수는 환경요인에 의해 영향을 받는다. 습기, 녹, 시공중의 작업성 등. 토크쉬어볼트의 토크계수의 변동에 기인하여 볼트에 도입된 축력을 예측하는 매우 어렵다. 이런 이유로 시공중인 볼트 축력을 측정하고, 체결력을 검증하는 것은 필수적이다. 이 연구에서, 볼트에 도입된 하중을 확인하기 위해 시작품 제작이 계획되었다. 시작품의 알고리즘은 토크쉬어 전동렌치에서 얻은 전기에너지와 유압축력기에서 얻은 축력과의 상관관계를 구성한 것이다. 직접축력을 계측하는 회귀분석식은 미니탭 프로그램을 이용한 통계학적인 분석방법에서 구한 것이다. 이 시작품은 상용 토크렌치에 견줄만한 인장력을 평가하는 신뢰성이 있는 도구라고 판단된다.