An Experimental Study on the Relaxation of Bolts

Abid, Мuhammad; Khalil, Muhammad; Wajid, Hafiz Abdul

doi:10.31436/iiumej.v16i1.539

Cited by 5 publications

(3 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Appropriate pre-tensioning of a bolt makes it less sensitive to fatigue and prevents it from self-loosening when subjected to extreme vibration, stress, or temperature cycles [ 1 ]. Both the initial magnitude and the clamping force’s ability to be maintained over time have an effect on the behavior and condition of the bolted joints [ 2 ]. As a result, improperly adjusted bolt pre-tensioning can lead to a number of issues in the joints, such as joint separation [ 1 ], bolt fatigue failure [ 3 ], and nut vibration loosening [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

PMUTs Arrays for Structural Health Monitoring of Bolted-Joints

et al. 2023

View full text Add to dashboard Cite

Micro-electro-mechanical systems (MEMS) have enabled new techniques for the miniaturization of sensors suitable for Structural Health Monitoring (SHM) applications. In this study, MEMS-based sensors, specifically Piezoelectric Micromachined Ultrasonic Transducers (PMUT), are used to evaluate and monitor the pre-tensioning of a bolted joint structural system. For bolted joints to function properly, it is essential to maintain a suitable level of pre-tensioning. In this work, an array of PMUTs attached to the head and to the end of a bolt, serve as transmitter and receiver, respectively, in a pitch-catch Ultrasonic Testing (UT) scenario. The primary objective is to detect the Change in Time of Flight (CTOF) of the acoustic wave generated by the PMUT array and propagating along the bolt’s axis between a non-loaded bolt and a bolt in service. To model the pre-tensioning of bolted joints and the transmission of the acoustic wave to and from a group of PMUTs through the bolt, a set of numerical models is created. The CTOF is found to be linearly related to the amount of pre-tensioning. The numerical model is validated through comparisons with the results of a preliminary experimental campaign.

show abstract

Section: Introductionmentioning

confidence: 99%

PMUTs Arrays for Structural Health Monitoring of Bolted-Joints

et al. 2023

View full text Add to dashboard Cite

show abstract

“…In addition, many researchers have studied the preload loss caused by embedding. Abid et al 7 deemed that embedding was an important cause of preload loss. Zhang et al studied the preload loss behavior of CFRP bolted joint under axial cyclic loading.…”

Section: Introductionmentioning

confidence: 99%

Preload loss of CFRP bolted joint without rotation under transverse and axial loading

Yang

Chen

et al. 2023

Advances in Mechanical Engineering

View full text Add to dashboard Cite

There are a large number of CFRP-steel bolted joints with jet nuts subjected to transverse and axial load in aircraft structures, which have passed standard testing of locking characteristics of fasteners under transverse loading conditions. This fastener has a great preload loss and no rotation loosening occurs. Based on the observation, we designed a biaxial loading experiment for CFRP bolted joint, and measured the preload and loosening angle under different initial preload. The biaxial research suggests that compared with the uniaxial loading condition, the preload loss is larger, the rotation is minimal and only appears in the early stage of test, and there are obvious indentations on the surface of CFRP panel. Embedment as an important factor leads to the preload loss due to the weak ability of CFRP panel suffering out of plane load. In order to study the effect of embedment, the relationship between stress S22 and indentation depth under different preload, the relationship between biaxial load amplitude and embedding depth, and the ratio of the preload loss caused by embedding to the total preload loss are revealed by finite element analysis.

show abstract

“…The notions of short-term relaxation and long-term relaxation are used in order to distinguish between two inherently different causes for relaxation [3]. The initial preload losses increase with an increase in preload force.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of preload losses in high strength bolts under cyclic loading

Fric

Veljković²,

Mišković

et al. 2021

JCE

View full text Add to dashboard Cite

Slip-resistant shear connections with preloaded bolts have traditionally been used in steel structures exposed to cyclic / fatigue loading or in cases when bolt slipping or connection deformations should be restricted. Hence, shear load is transferred through friction surfaces rather than through contact between the bolt surface and the hole. The main influencing parameters determining slip resistance of the connection are the friction between contact surfaces and the bolt preload level. This paper presents an experimental study of preloaded bolted connections under cyclic load, the main objective being to investigate the influence of cyclic load on the losses of preload force in high strength bolts and lock bolts.

show abstract

An Experimental Study on the Relaxation of Bolts

Cited by 5 publications

References 9 publications

PMUTs Arrays for Structural Health Monitoring of Bolted-Joints

PMUTs Arrays for Structural Health Monitoring of Bolted-Joints

Preload loss of CFRP bolted joint without rotation under transverse and axial loading

Experimental investigation of preload losses in high strength bolts under cyclic loading

Contact Info

Product

Resources

About