Detection of the Broken Wires in the Cables’ Hidden Parts (Anchorings) by Acoustic Emission

2006 ◽  
Vol 13-14 ◽  
pp. 345-350 ◽  
Author(s):  
Hasnae Zejli ◽  
A. Laksimi ◽  
C. Tessier ◽  
L. Gaillet ◽  
S. Benmedakhene
Keyword(s):  
Acoustic Emission ◽  
Elastic Energy ◽  
Necessary Conditions ◽  
Contact Strength ◽  
Surface Conditions ◽  
Stay Cables ◽  
Dynamic Bending ◽  
Steel Cables

Steel cables play an indispensable role in a number of rather diverse fields of applications. They are extensively used in suspension and stay cables bridges. It is important to be able to detect as precociously as possible the defects affecting their performance. They can present a healthy aspect over their observable lengths and be damaged in the hidden parts (anchorages). In this present study, Acoustic Emission (AE) is used in order to detect and to locate broken wires in the anchorage zones. The study of the behaviour of a broken wire in a cable under dynamic bending contribute to understand the origin of AE source and to discuss the necessary conditions of vibrating for detection. In this case, the phenomene source of AE is related to interwire friction caused by the redistribution of elastic energy on the recovery length of the broken wire and the repetition of the process joining-slip between wires. AE parameters are very influenced by the change of surface conditions, contact strength between wires and the recovery length of the broken wire. Several cables are evaluated in different surface conditions i.e. corroded, dry and oiled.

The Secant Modulus of Elasticity of Stay Cables Stiffened by Secondary Steel Cables

Volume 3 ◽  
2004 ◽  
Author(s):  
Igino Mura
Keyword(s):  
Modulus Of Elasticity ◽  
Tangent Modulus ◽  
Secant Modulus ◽  
General Validity ◽  
Stay Cables ◽  
Steel Cables

Provided herein is the expression for calculation of the secant modulus of elasticity E*HS for stay cables stiffened with the application of elastic stiffening cables. The solution obtained is compared with the formulation of the tangent modulus of elasticity EiH proposed by Tschemmernegg and Obholzer. The general validity of the formula obtained is shown, as are the significant limitations inherent in the use of the tangent expression for finite tensional ranges in the stays for purposes of comparison. It is found that vertical cables are more effective than inclined ones, although their use implies greater limitations because of fatigue phenomena and the danger of unloading.

Nonlinear vibrations of CFRP cables excited by periodic motions of supports in cable-stayed bridges

2018 ◽  
Vol 24 (22) ◽  
pp. 5249-5260 ◽  
Author(s):  
Kuihua Mei ◽  
Guoqing Jin ◽  
Shengjiang Sun
Keyword(s):  
Numerical Solutions ◽  
Geometrical Nonlinearity ◽  
Stay Cable ◽  
Periodic Motions ◽  
Nonlinear Dynamic Model ◽  
Steel Cable ◽  
Traffic Loading ◽  
Stay Cables ◽  
Vibration Responses ◽  
Steel Cables

Owing to its excellent non-corrosiveness and fatigue resistance, a carbon fiber-reinforced polymer (CFRP) stay cable is an ideal alternative to overcome corrosion and fatigue problems associated with the traditional steel cable. However, stay cables are prone to various oscillations under wind, rain, and traffic loading. The vibrations of CFRP stay cables excited by periodic motions of the girder and/or pylons were studied and compared with those of steel cables. A nonlinear dynamic model for in-plane and out-of-plane vibrations of stay cables was proposed. Particularly, the geometrical nonlinearity of the cables was considered in this model. On the basis of this model, numerical solutions were obtained for CFRP cables and steel cables with the same conditions. Furthermore, the effects of important parameters on vibrations were discussed. These parameters included cable tensions, excitation amplitudes, and damping ratios. Results demonstrate that small excitation amplitudes may lead to forced vibrations or parametric vibrations with substantial amplitudes when natural frequencies of the cables are approximately half or one time of excitation frequencies. The maximal vibration responses of CFRP cables are weaker than those of steel cables when their lengths are substantial. As static tensions of the cables decrease, the “beating” frequencies and the maximal amplitudes of the vibrations increase.

Study on Acoustic Emission of Rock Damage Based on Physical Cellular Automata

2012 ◽  
Vol 170-173 ◽  
pp. 179-182
Author(s):  
Zhi Tao Ma ◽  
Yong Ping Wang ◽  
Sai Jiang Liang ◽  
Dong Chuan Gao
Keyword(s):  
Nonlinear Dynamics ◽  
Acoustic Emission ◽  
Cellular Automata ◽  
Elastic Energy ◽  
Physical Phenomenon ◽  
New Method ◽  
Rock Deformation ◽  
Dynamics Analysis ◽  
Rock Damage ◽  
Analysis Method

Rock acoustic emission a physical phenomenon during the rock deformation, it is also an effective method used to study the properties of rock damage. In this article, from the aspects of elastic energy, a discrete nonlinear dynamics analysis method was established based on physical cellular automata. Using this new method, the properties of acoustic emission during the rock deformation and damage were studied, and the results were compared with related previous research achievements, and the results show that this new method based on cellular automata is reasonable and effective.

scholarly journals Study on unloading energy characteristics of limestone in different crossing sections

2020 ◽  
Vol 165 ◽  
pp. 03015
Author(s):  
Yilin Liao ◽  
Jianfeng Liu ◽  
Qiangxing Zhang ◽  
Zhicheng Li ◽  
Deng Xu ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Elastic Energy ◽  
Test System ◽  
Coal Measure ◽  
Dissipation Energy ◽  
Energy Characteristics ◽  
Peak Energy ◽  
Confining Pressures ◽  
Energy Ratios ◽  
Main Factor

In order to study the energy characteristics of limestone under different initial confining pressures and different unloading rates, based on MTS815 flex test GT rock mechanics test system and acoustic emission (AE) 3D positioning real-time monitoring system, the unloading test and acoustic emission synchronous monitoring of limestone are carried out. The results show that: (1) the pre peak energy process is dominated by energy accumulation, but mainly occurs in the loading stage. The proportion of energy in the unloading stage is basically unchanged, and the proportion of elastic energy is more than 0.9, which fluctuates only before the failure. During the failure, the proportion of energy in the stress drop changes dramatically, and the proportion of elastic energy decreases rapidly to 0. (2) In the coal measure strata, the energy dissipation is the main factor, the dissipation energy and its proportion increase rapidly, while in the front of coal measure strata, the energy release is the main factor, the elastic energy decreases rapidly and the dissipation energy does not increase. (3) The proportion of coal bearing strata in front of coal bearing strata is 0.68 and 0.57 respectively. Unloading elastic energy ratios before coal-bearing strata and coal-bearing strata are 0.824 and 0.876, respectively.

Dynamic Bending Stresses near the Ends of Parallel-Bundle Stay Cables

2003 ◽  
Vol 13 (1) ◽  
pp. 64-68 ◽  
Author(s):  
Carlos A. Prato ◽  
Marcelo A. Ceballos
Keyword(s):  
Stay Cables ◽  
Bending Stresses ◽  
Dynamic Bending

Deformation and Acoustic Emission during Nanoindentation on Single Crystal MgO (001) Plane

2009 ◽  
Vol 76-78 ◽  
pp. 404-409 ◽  
Author(s):  
Zhi Gang Dong ◽  
Han Huang ◽  
Ren Ke Kang
Keyword(s):  
Acoustic Emission ◽  
Single Crystal ◽  
Energy Release ◽  
Elastic Deformation ◽  
Elastic Energy ◽  
Elastoplastic Deformation ◽  
Acoustic Emission Monitoring ◽  
Emission Monitoring ◽  
Three Stages

Nanoindentation tests with the aid of acoustic emission monitoring were performed on single crystal MgO (001) plane to investigate the deformation of MgO under high indentation pressures. The results indicated that the deformation of MgO under nanoindentation with a sharp indenter could be classified into three stages: elastic deformation, elastoplastic deformation, and fragmentation. The elastic energy release and fracture occurred could be identified using acoustic emission signals.

scholarly journals Improvement in Contact Strength of Si3N4/SiC Composite by Crack Healing

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Koji Takahashi ◽  
Keita Takahashi ◽  
Kotoji Ando
Keyword(s):  
Acoustic Emission ◽  
Cutting Tool ◽  
Indentation Test ◽  
Machining Process ◽  
Surface Cracks ◽  
Contact Strength ◽  
Crack Healing ◽  
Machining Processes ◽  
Contact Loading ◽  
Ceramic Components

Ceramics have been used as bearing and cutting tool components, which are subjected to contact loading during their operation. The presence of surface cracks on these components decreases their contact strength. Thus, the reliability of ceramic components can be increased by improving their contact strength through crack healing. In the present study, the effects of crack healing on the contact strength of a silicon carbide-(SiC-) reinforced silicon nitride (Si3N4) composite subjected to various machining processes were investigated. The contact strength of this composite was evaluated using a sphere indentation test in which acoustic emission was used. The results showed that the contact strength of the composite improved when it was subjected to crack healing in combination with rapping; this was true even when the composite had cracks due to a heavy machining process.

Sign in / Sign up

Export Citation Format

Share Document