Novel Formulation of the Tightening and Breakaway Torque Components in Threaded Fasteners

Nassar, Sayed A.; Yang, Xianjie

doi:10.1115/1.2767354

Cited by 42 publications

(25 citation statements)

References 12 publications

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“…However this relationship is highly affected by friction of a bolted joint. This is confirmed by Nassar, S. A. et al in their experiments [18][19][20][21][22], which identified several factors affecting the relationship between input torque and preload generate at the bolt. They are the surface finish, tightening speed, coefficient friction of the bolt [21], and the lubricant used [22].…”

Section: Preload Of Bolted Jointssupporting

confidence: 68%

“…To overcome this difficulty, another approach is used to identify the transduction matrix experimentally. As can be seen from the transduction matrix in Equation (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22), electrical input (E and i) and mechanical output (T m and Ω m ) of the brushed DC motor are linearly related. When there is n-number of E, i, T m ,…”

Section: Experimental Identification Of Transduction Matrixmentioning

confidence: 99%

“…By substituting Equations (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24) and into Equation (5 the moving average for every 500 points is applied to the result. Equation (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23) shows that the response of the bolted joint is linearly related with the excitation torque of bolted joint. A higher excitation value leads to a higher response value.…”

Section: Angular Response Of Bolted Joint To Transverse Vibrationmentioning

confidence: 99%

“…21 shows that two regions of distinct patterns in the relationship between torque and preload during tightening process. In the first region, the relationship is…”

mentioning

confidence: 94%

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Tightening and loosening of bolted joint

Tanra¹

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A bolted joint is a common joint encountered in mechanical structures or machine design. Its tightness is important in order to secure the structure or machine it is attached to. A proper tightness is installed at a bolted joint to resist static and dynamic loading it is subjected to. When tightness is not sufficient, it can cause failure such as loosening and in extreme cases, joint separation. In this project, a bolted joint and its tightness are objects being studied. The purpose of this project is to understand the factors affecting tightness of a bolted joint and causes of its loosening under dynamic loading (vibration). A DC motor with known transduction matrix was used as a device to measure mechanical condition of a bolted joint. By obtaining the 2x2 transduction matrix, mechanical output of a DC motor can be related with its electrical input. With this relation, a DC motor was used to tighten a bolted joint and measure its mechanical condition by controlling and measuring its electrical input. Based on this mechanical condition, tightness and dynamic condition of a bolted joint were obtained. The project is divided into 2 parts. In the first part, the tightening process of a bolted joint is studied. The experiment results show that torque is not sufficient in indicating tightness of a bolted joint. Under different friction conditions, tightness that is achieved by the same value of torque differs significantly. Thus, energy is used as a tightening indicator. With simultaneously measurement of torque and rotation speed, energy applied to a bolted joint can be measured. The experiment results show that energy is a better tightening indicator as compared to torque. In the second part, dynamic behavior of a bolted joint under dynamic loading is studied. First, mechanical impedance of a bolted joint is measured with usage of Hilbert Transform. The Hilbert Transform helps to obtain mechanical impedance in time domain. With this, change of mechanical impedance over a period of time can be monitored. By obtaining mechanical impedance, system properties can be Abstract ii derived from their relation. The results show that system properties of a bolted joint are affected by tightness of a bolted joint (preload), its surface condition and frequency of applied excitation. After obtaining system properties of a bolted joint, response of a bolted joint to a vibration, especially transverse vibration, can be calculated. The results show that a transverse vibration given to a bolted joint can cause loosening due to thread geometry and system properties of a bolted joint. Acknowledgment iii ACKNOWLEDGMENT I would like to praise my thanks to the God for the completion of this thesis report. I also would also like to thank my supervisor, Professor Ling Shih Fu, for his ideas, guidance and support in this research. Even in his busiest schedule, he still spends his time in discussing this research. Secondly, I would like to thanks my fellow friends, Lian Kar Foong, Wong Yoke Rong, Felicia Rezanda, Hossein Mousavi and Peng Xi...

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Section: Preload Of Bolted Jointssupporting

confidence: 68%

Section: Experimental Identification Of Transduction Matrixmentioning

confidence: 99%

Section: Angular Response Of Bolted Joint To Transverse Vibrationmentioning

confidence: 99%

“…21 shows that two regions of distinct patterns in the relationship between torque and preload during tightening process. In the first region, the relationship is…”

mentioning

confidence: 94%

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Tightening and loosening of bolted joint

Tanra¹

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“…After Housari, Nassar and Yang [16][17][18][19][20] established a more accurate mathematical model based on the relative sliding of the friction surface to solve the tangential force and the friction torque at the support surface and the thread under the cyclic transverse load.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study and Life Prediction of Bolt Loosening Life under Variable Amplitude Vibration

Yang

Che

Xiao

et al. 2019

Shock and Vibration

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The transverse vibration test of bolts has been designed with adoption of the fatigue tester to study the features of the loosening life of bolts. Firstly, the transverse vibration frequency has been changed, the effects of the amplitudes of displacement, velocity, and acceleration on the loosening life of bolts have been compared, and it has been confirmed that the transverse displacement amplitude is the main factor that affects bolt loosening in low-frequency vibration. Secondly, the loosening degree of the bolts preloaded standard under five displacement amplitude grades has been monitored and the bolt loosening situation has been expressed through the residual preload-vibration times curve. The data of each stage of residual preload under each displacement amplitude were summarized, and the displacement-life (D-N) curve of bolt loosening under different loosening situations (percentage of residual preload) which is referred to the material fatigue life S-N curve was drawn. Finally, the accumulation mechanism of bolt loosening has been studied and the linear accumulation model of bolt loosening has been set up through designing variable amplitude vibration tests at high-low and low-high displacement stages. Results show that, through the bolt loosening D-N curve, it can be found out that the bolt loosening life curve and the material fatigue life curve are with features of double line and high- and low-cycle boundary under the logarithmic coordinate. Linear accumulation of bolt loosening is with similar principle of linear damage accumulation of material fatigue. Therefore, the bolt loosening life can be predicted through bolt displacement-loosening life (D-N) curve attained from the experiment and the established linear accumulation model of bolt loosening.

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Experimental and Mechanical Analysis of the Yielding Support Behavior of a Novel Compact Yielding Anchor Cable

Wang,

Guo

et al. 2024

Rock Mech Rock Eng

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Novel Formulation of the Tightening and Breakaway Torque Components in Threaded Fasteners

Cited by 42 publications

References 12 publications

Tightening and loosening of bolted joint

Tightening and loosening of bolted joint

Experimental Study and Life Prediction of Bolt Loosening Life under Variable Amplitude Vibration

Experimental and Mechanical Analysis of the Yielding Support Behavior of a Novel Compact Yielding Anchor Cable

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