Forced vibration behaviour and crack detection of cracked beams using instantaneous frequency

2005 ◽  
Vol 38 (5) ◽  
pp. 411-419 ◽  
Author(s):  
S. Loutridis ◽  
E. Douka ◽  
L.J. Hadjileontiadis
Keyword(s):  
Instantaneous Frequency ◽  
Forced Vibration ◽  
Crack Detection ◽  
Cracked Beams

Crack detection and vibration behavior of cracked beams

2001 ◽  
Vol 79 (16) ◽  
pp. 1451-1459 ◽  
Author(s):  
P.N. Saavedra ◽  
L.A. Cuitiño
Keyword(s):  
Crack Detection ◽  
Vibration Behavior ◽  
Cracked Beams

scholarly journals Exact receptance function and receptance curvature of a clamped-clamped continuous cracked beam

2019 ◽  
Vol 41 (4) ◽  
pp. 349-361
Author(s):  
Nguyen Viet Khoa ◽  
Cao Van Mai ◽  
Dao Thi Bich Thao
Keyword(s):  
Numerical Simulations ◽  
Frequency Domain ◽  
Crack Detection ◽  
Harmonic Excitation ◽  
Second Derivative ◽  
Cracked Beam ◽  
Cracked Beams

The receptance function has been studied and applied widely since it interrelates the harmonic excitation and the response of a structure in the frequency domain. This paper presents the derivation of the exact receptance function of continuous cracked beams and its application for crack detection. The receptance curvature is defined as the second derivative of the receptance. The influence of the crack on the receptance and receptance curvature is investigated. It is concluded that when there are cracks the receptance curvature has sharp changes at the crack positions. This can be applied for the crack detection purpose. In this paper, the numerical simulations are provided.

A study on the crack detection in beams using linear and nonlinear normal modes

2019 ◽  
Vol 23 (7) ◽  
pp. 1305-1321
Author(s):  
Yildirim Serhat Erdogan
Keyword(s):  
Normal Mode ◽  
Crack Detection ◽  
Normal Modes ◽  
Element Model ◽  
Nonlinear Normal Modes ◽  
Crack Identification ◽  
Crack Location ◽  
Linear And Nonlinear ◽  
Nonlinear Normal ◽  
Cracked Beams

Linear and nonlinear normal mode motions may provide promising information about the condition of mechanical structures under small and large amplitude vibrations, respectively. In this view, this study investigates the nonlinear dynamics of cracked beams through use of the nonlinear mode motion and extends the crack identification methods that utilize the linear characteristics to nonlinear vibrating structures. At first, the nonlinear normal modes of the intact and cracked beams are calculated by a continuation algorithm. A finite element model of a geometrically nonlinear prismatic beam was created based on crack stress intensity. Subsequently, a method based on normal mode motion and minimization of strain energy, which is valid for linear and nonlinear vibrating beams, was developed as an optimization problem. To this end, hybrid optimization was also used due to its capability in finding global minimum along with its computational efficiency. It was shown that the proposed crack detection technique is applicable to beams vibrating in linear and/or nonlinear regimes and well capable of detecting both crack location and severity.

Explicit Assessment of the Forced Vibration of Multi-cracked Beams with Uncertain Damage Intensity

2020 ◽  
pp. 1718-1728
Author(s):  
Francesco Cannizzaro ◽  
Nicola Impollonia ◽  
Giuseppe Cocuzza Avellino ◽  
Salvatore Caddemi ◽  
Ivo Caliò
Keyword(s):  
Forced Vibration ◽  
Cracked Beams

scholarly journals Exact Receptance Function of Cracked Beams and Its Application for Crack Detection

2019 ◽  
Vol 2019 ◽  
pp. 1-19
Author(s):  
Khoa Viet Nguyen ◽  
Mai Van Cao
Keyword(s):  
Boundary Conditions ◽  
Numerical Simulations ◽  
Frequency Domain ◽  
Crack Detection ◽  
Harmonic Excitation ◽  
General Boundary ◽  
Second Derivative ◽  
General Boundary Conditions ◽  
Cracked Beams

The receptance function is very important which interrelates the harmonic excitation and the response of a structure in the frequency domain. This paper presents the exact receptance function of cracked beams. In this work, the “receptance curvature” is defined as the second derivative of the receptance. The influence of the crack on the receptance curvature is investigated. The results show that when there are cracks, the receptance curvature is influenced significantly at crack positions. This might be useful for the detection of cracks. In this paper, the derivation of exact receptance of the beam with general boundary conditions is presented, and the numerical simulations are provided.

Modelling of a Beam with a Breathing Edge Crack and Some Observations for Crack Detection

2002 ◽  
Vol 8 (5) ◽  
pp. 673-693 ◽  
Author(s):  
A. Nandi ◽  
S. Neogy
Keyword(s):  
Edge Crack ◽  
Crack Detection ◽  
Spectral Characteristics ◽  
Crack Size ◽  
Small Displacement ◽  
Harmonic Load ◽  
Cracked Beam ◽  
Frequency Spectra ◽  
Proposed Model ◽  
Cracked Beams

The breathing behaviour of closing cracks has been adequately simulated as a small-displacement, frictionless contact problem. The problem of a beam with an edge crack subjected to harmonic loading has been considered as a plane problem and an attempt is made to solve it by using finite elements employing eight-node plane isoparametric elements. The proposed model allows the crack size and position to be varied. Another physically important problem of a cantilever beam held between two heavy jaws at the top and bottom, which are not equally flushed, is considered. This beam is also excited by a harmonic load at the tip. The contact model and a simple single degree of freedom model are used to solve the problem. Both the above problems (cracked beam and beam in offset jaws) show presence of integral multiples of the forcing frequency in their frequency spectra. An important observation regarding cracked beams and beams with imperfect support is made. If the forcing frequency is such that it coincides or is close to any one of the integral sub-multiples (1/ n) of the first natural frequency of the system, then the nth harmonic of the forcing frequency will considerably shoot up. This effect is highly pronounced for the case n = 2 and this observation may be used to detect cracks in beams as small as 2.5% of the depth. For cracked beams, the even harmonics are considerably stronger than the odd ones. As the crack size decreases, the odd harmonics become weaker. For a 2.5% crack only the second and fourth harmonics are visible in an 80 dB scale, with the former being the stronger. However, it is important to note that cracked beams and beams with imperfect support have closely similar spectral characteristics and so due caution must be exercised during crack detection.

Three-Dimensional Ultrasonic Crack Detection in Anisotropic Materials

1997 ◽  
Vol 9 (2) ◽  
pp. 59-79 ◽  
Author(s):  
J. Mattsson ◽  
A. J. Niklasson ◽  
A. Eriksson
Keyword(s):  
Crack Detection ◽  
Three Dimensional ◽  
Anisotropic Materials

Status of nondestructive control of transport function metal products at JSC EVRAZ NTMK

2020 ◽  
Vol 76 (6) ◽  
pp. 586-590
Author(s):  
S. P. Bersenev ◽  
E. M. Slobtsova
Keyword(s):  
Crack Detection ◽  
Middle Part ◽  
Control Line ◽  
Magnetic Powder ◽  
Nondestructive Control ◽  
Automated Control ◽  
Ultrasonic Control ◽  
Acoustic Contact ◽  
In Series

Achievements in the area of automated ultrasonic control of quality of rails, solid-rolled wheels and tyres, wheels magnetic powder crack detection, carried out at JSC EVRAZ NTMK. The 100% nondestructive control is accomplished by automated control in series at two ultrasonic facilities RWI-01 and four facilities УМКК-1 of magnetic powder control, installed into the exit control line in the wheel-tyre shop. Diagram of location, converters displacement and control operations in the process of control at the facility RWI-01 presented, as well as the structural diagram of the facility УМКК-1. The automated ultrasonic control of rough tyres is made in the tyres control line of the wheel-tyre shop at the facility УКБ-1Д. The facility enables to control internal defects of tyres in radial, axis and circular directions of radiation. Possibilities of the facility УКБ-1Д software were shown. Nondestructive control of railway rails is made at two facilities, comprising the automated control line of the rail and structural shop. The УКР-64Э facility of automated ultrasonic rails control is intended to reveal defects in the area of head, web and middle part of rail foot by pulse echo-method with a immersion acoustic contact. The diagram of rail P65 at the facility УКР-64Э control presented. To reveal defects of the macrostructure in the area of rail head and web by mirror-shadow method, an ultrasonic noncontact electromagnetic-acoustic facility is used. It was noted, that implementation of the 100% nondestructive control into the technology of rolled stuff production enabled to increase the quality of products supplied to customers and to increase their competiveness.

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