5235 Influences of Tightening Conditions of bolted Joint on Loosening-Fatigue characteristics under Transverse Vibration

Fatigue tests under transverse vibration were performed for three separate tightening conditions to investigate the grip length and the engaging thread length in this study. The relationships between the apparent fatigue limit (the highest amplitude of transverse vibration force which can be applied to the bolted joint without generating fatigue) and the real fatigue limit of bolt material also were investigated. Results showed that apparent transverse fatigue limit decreased if the grip length was long. And relationships of the apparent fatigue limit and the real fatigue limit were different in each tightening conditions depending on the bending moment at the root of the first thread.

Download Full-text

A Study of Self-Loosening and Fatigue Failure of Bolted Joint under Transverse Vibration - Influences of Property Class of Bolt and Plastic Region Tightening

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.353-358.2037 ◽

2007 ◽

Vol 353-358 ◽

pp. 2037-2040 ◽

Cited By ~ 3

Author(s):

Shinji Hashimura

Keyword(s):

Fatigue Limit ◽

Fatigue Failure ◽

Transverse Vibration ◽

Plastic Region ◽

Fatigue Tests ◽

Bolted Joints ◽

Bolted Joint ◽

Transverse Vibrations ◽

Fatigue Characteristics ◽

Long Life

In our previous study, loosening-fatigue tests under small transverse vibrations had been performed to elucidate bolt behavior and loosening-fatigue mechanism in the long life region. In this study, the influences of bolt property class and the plastic region tightening on loosening-fatigue characteristics under transverse vibration have been investigated. Result shows that bolt property class has little influence on the loosening-fatigue limits under transverse vibration. Result also shows that the transverse loosening-fatigue limit of the bolt which has been tightened to within the plastic region is lower than the transverse loosening-fatigue limit of the bolt that has been tightened to within the elastic region. This result is the opposite of the result of the axial fatigue characteristics of bolted joints.

Download Full-text

Fatigue Characteristics of Nonferrous Bolts

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.577-578.417 ◽

2013 ◽

Vol 577-578 ◽

pp. 417-420 ◽

Cited By ~ 2

Author(s):

Shinji Hashimura ◽

Tetsuya Torii ◽

Yukio Miyashita ◽

Shigeru Yamanaka ◽

Genki Hibi

Keyword(s):

Aluminum Alloy ◽

Magnesium Alloy ◽

Fatigue Tests ◽

Bolted Joint ◽

Fatigue Characteristics ◽

Axial Fatigue

Fatigue characteristics of bolted joint tightened with a steel bolt have been discussed extensively. However the fatigue characteristics of bolted joint tightened with a nonferrous bolt have not been sufficiently discussed. In this study, two types of fatigue tests, axial fatigue tests and transverse fatigue tests, for nonferrous bolts were conducted. The nonferrous bolts used in this study made of AZ31 and AZX912 magnesium alloy and A5056 aluminum alloy. The results of both fatigue tests showed that the fatigue limits of the A5056 bolt were the highest of all. The fatigue limits of two kinds of the magnesium alloy bolts were almost the same in both fatigue tests. However the ration of the axial fatigue limits to the transverse fatigue limits were different according to the bolt materials.

Download Full-text

Transverse Vibration Testing Research for 6.8 Grades Bolted Joint Used on Transmission Tower

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.470.567 ◽

2013 ◽

Vol 470 ◽

pp. 567-571

Author(s):

Xiao Hao Dai ◽

Yan Ting Feng ◽

Xiao Guang Niu ◽

Hui Fan ◽

Qiang Wang ◽

...

Keyword(s):

Transverse Vibration ◽

Decisive Role ◽

Bolted Joint ◽

Transmission Tower ◽

Vibration Testing ◽

Second Stage ◽

Reduced Rate ◽

Test Result

Five groups of vibration experiments were carried out on the 6.8 grades and M20 bolts and nuts that used on transmission tower. The test result shows that the basic way to improve the anti-loosening property was increasing the initial preload. Both increasing initial torque and appending lubrication can obviously increase the initial preload, however appending lubrication may reduce it's anti-loosening property under the situation of same preload. In the vibrating process the second stage plays a decisive role for anti-loosening property, it can be expressed as reduced rate “K” of the preload.

Download Full-text