Vibration and Acoustic Emission of Linear-Guideway Type Recirculating Ball Bearings With a Millimeter-Sized Artificial Defect in the Carriage

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Hiroyuki Ohta ◽  
Kazuya Matsuura ◽  
Soichiro Kato ◽  
Yutaka Igarashi
Keyword(s):  
Acoustic Emission ◽  
Acoustic Emissions ◽  
Linear Velocity ◽  
Experimental Results ◽  
Ball Bearings ◽  
Artificial Defect ◽  
Collision Model ◽  
Defect Type ◽  
Defect Angle

This paper deals with vibrations and acoustic emissions (AEs) of linear-guideway type recirculating ball bearings with a millimeter-sized artificial defect in the carriage. The vibration and AE of one normal bearing without a defect (Type N), and six defective bearings (Types D1–D6) were measured using a linear velocity of 1 m/s. The defects in the bearings range from 1.87 mm to 6.77 mm in length, 2.45 mm to 3.80 mm in width, and 23.3 μm to 68.0 μm in depth. The experimental results show that the pulse amplitudes of the vibrations and AE (both the peak-to-peak and RMS values) of the defective bearings have a tendency to be greater than those of the normal bearing. Both the measured vibration and AE components over 30 kHz increased in the carriages with defects. To explain these increases in the defective bearings, a collision model with balls and one defect in the carriage is presented. That collision model shows that the increases in both the vibrations and AE of the defective bearings are caused by increases in the defect angle. A reasonable correlation exists between the presented collision model and the measured vibrations or AE of the defective bearings.

Effects of Grease Types on Vibration and Acoustic Emission of Defective Linear-Guideway Type Recirculating Ball Bearings

2010 ◽  
Author(s):  
Hiroyuki Ohta ◽  
Shinya Hayashi ◽  
Soichiro Kato ◽  
Yutaka Igarashi
Keyword(s):  
Acoustic Emission ◽  
Acoustic Emissions ◽  
Experimental Results ◽  
Ball Bearings ◽  
Oil Viscosity ◽  
Grease Lubrication ◽  
Base Oil ◽  
Defect Angle

In this paper, vibrations and acoustic emissions (AEs) of defective linear-guideway type recirculating ball bearings under grease lubrication were measured. The experimental results show that the vibration and AE amplitudes (the pulse amplitudes, the RMS values) of both the normal and defective bearings have a tendency to be reduced when a grease with higher base oil viscosity is used. Under the same type of grease, the RMS values of the vibrations and AE of the defective bearings increase as the defect angle increases. However, the increases of the RMS values due to increased defect angle are reduced when a grease with higher base oil viscosity is used.

Effects of Grease Types on Vibration and Acoustic Emission of Defective Linear-Guideway Type Recirculating Ball Bearings

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Hiroyuki Ohta ◽  
Shinya Hayashi ◽  
Soichiro Kato ◽  
Yutaka Igarashi
Keyword(s):  
Experimental Results ◽  
Ball Bearings ◽  
Oil Viscosity ◽  
Ball Impact ◽  
Artificial Defect ◽  
Base Oil ◽  
Impact Tests ◽  
Impact Forces ◽  
The Impact ◽  
Defect Angle

This paper deals with effects of grease types on vibrations and acoustic emissions (AEs) of linear-guideway type recirculating ball bearings with a millimeter-sized artificial defect in the carriage. First, the vibration and AE of one normal bearing without a defect (Type N) and six defective bearings (Types D1–D6) were measured using a linear velocity of 1 m/s. Three types of grease are used for the lubrication of test bearings. The experimental results show that the vibration and AE amplitudes (the pulse amplitudes, the root-mean-square (RMS) values, and component amplitudes in the spectra) of both the normal and defective bearings have a tendency to be reduced when a grease with higher base oil viscosity is used. Under the same type of grease, the RMS values of the vibrations and AE of the defective bearings increase as the defect angle increases. However, the increases of the RMS values due to increased defect angle (the increasing rates of the RMS values) are reduced when a grease with higher base oil viscosity is used. To explain these experimental results, grease impact tests are carried out. The grease impact tests show that a grease with higher base oil viscosity reduces the impact velocity and the maximum impact forces. This implies that a grease with higher base oil viscosity generate greater viscous resistance to balls in the test bearings then reduces the ball impact forces in the ball circulation collisions and ball-defect collisions. Because of the reduction of the ball impact forces, both the vibration and AE amplitudes as well as the increasing rate of the RMS values are reduced.

A Novel Method for Grinding Wheel Setting Based on Acoustic Emissions

2016 ◽  
Vol 874 ◽  
pp. 79-84 ◽  
Author(s):  
Xiang Long Zhu ◽  
Zhen Hua Jiao ◽  
Ren Ke Kang ◽  
Zi Guang Wang ◽  
Hui Xu
Keyword(s):  
Acoustic Emission ◽  
Negative Impact ◽  
Acoustic Emissions ◽  
Experimental Results ◽  
Grinding Wheel ◽  
Detection Accuracy ◽  
Grinding Process ◽  
Novel Method ◽  
Ae Signals ◽  
Better Than

Wheel setting is difficult in a grinding process and may directly apply a negative impact on grinding accuracy and efficiency. This study presents a novel method for grinding wheel setting based on acoustic emissions. The method experimentally detects the acoustic emission (AE) signals that come from the touch-down of the grinding wheel with the workpiece. The experimental results show that the measured AE signals monotonically increase with grinding depth and can be used for detection of wheel setting in a grinding process with a detection accuracy better than 0.5μm.

Vibration and Acoustic Emission of Linear-Guideway Type Recirculating Linear Ball Bearings With One Artificial Defect in the Carriage

2008 ◽  
Author(s):  
Hiroyuki Ohta ◽  
Kazuya Matsuura ◽  
Soichro Kato ◽  
Yutaka Igarashi
Keyword(s):  
Acoustic Emission ◽  
Ball Bearings ◽  
Artificial Defect ◽  
Detection Techniques ◽  
Increasing Demand

In machines with linear-guideway type recirculating linear ball bearings (linear bearings), to prevent shutdown of machines caused by unexpected-failures of linear bearings, there has been an increasing demand for the development of defect (especially flaking) detection techniques of linear bearings by using vibration or acoustic emission (AE) measurements. Although studies [1–3] on vibrations of linear bearings without defects have been carried out, work on vibrations and AE of defective linear bearings are few [4, 5].

Guided Wave Acoustic Emission from Fatigue Crack Growth in Aluminium Plate

2006 ◽  
Vol 13-14 ◽  
pp. 23-28 ◽  
Author(s):  
C.K. Lee ◽  
Jonathan J. Scholey ◽  
Paul D. Wilcox ◽  
M.R. Wisnom ◽  
Michael I. Friswell ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Elastic Waves ◽  
Fatigue Cracks ◽  
Guided Wave ◽  
Experimental Results ◽  
Multiple Reflections ◽  
Alloy Plate

Acoustic emission (AE) testing is an increasingly popular technique used for nondestructive evaluation (NDE). It has been used to detect and locate defects such as fatigue cracks in real structures. The monitoring of fatigue cracks in plate-like structures is critical for aerospace industries. Much research has been conducted to characterize and provide quantitative understanding of the source of emission on small specimens. It is difficult to extend these results to real structures as most of the experiments are restricted by the geometric effects from the specimens. The aim of this work is to provide a characterization of elastic waves emanating from fatigue cracks in plate-like structures. Fatigue crack growth is initiated in large 6082 T6 aluminium alloy plate specimens subjected to fatigue loading in the laboratory. A large specimen is utilized to eliminate multiple reflections from edges. The signals were recorded using both resonant and nonresonant transducers attached to the surface of the alloy specimens. The distances between the damage feature and sensors are located far enough apart in order to obtain good separation of guided-wave modes. Large numbers of AE signals are detected with active fatigue crack propagation during the experiment. Analysis of experimental results from multiple crack growth events are used to characterize the elastic waves. Experimental results are compared with finite element predictions to examine the mechanism of AE generation at the crack tip.

Simultaneous Monitoring of Rolling-Element and Journal Bearings Using Analysis of Structure-Born Ultrasound Acoustic Emissions

2010 ◽  
Author(s):  
A. Albers ◽  
M. Dickerhof
Keyword(s):  
Acoustic Emission ◽  
Acoustic Emissions ◽  
Piezoelectric Sensor ◽  
Journal Bearings ◽  
Rolling Element Bearings ◽  
Acoustic Emission Sensor ◽  
Outer Race ◽  
Rolling Element ◽  
Characteristic Values ◽  
Acoustic Emission Technology

The application of Acoustic Emission technology for monitoring rolling element or hydrodynamic plain bearings has been addressed by several authors in former times. Most of these investigations took place under idealized conditions, to allow the concentration on one single source of emission, typically recorded by means of a piezoelectric sensor. This can be achieved by either eliminating other sources in advance or taking measures to shield them out (e. g. by placing the acoustic emission sensor very close to the source of interest), so that in consequence only one source of structure-born sound is present in the signal. With a practical orientation this is often not possible. In point of fact, a multitude of potential sources of emission can be worth considering, unfortunately superimposing one another. The investigations reported in this paper are therefore focused on the simultaneous monitoring of both bearing types mentioned above. Only one piezoelectric acoustic emission sensor is utilized, which is placed rather far away from the monitored bearings. By derivation of characteristic values from the sensor signal, different simulated defects can be detected reliably: seeded defects in the inner and outer race of rolling element bearings as well as the occurrence of mixed friction in the sliding surface bearing due to interrupted lubricant inflow.

Anisotropy in the Dicke Narrowing of Rotational Raman Lines (A New Measure of the Nonsphericity of Intermolecular Forces)

1972 ◽  
Vol 50 (8) ◽  
pp. 778-782 ◽  
Author(s):  
B. K. Gupta ◽  
S. Hess ◽  
A. D. May
Keyword(s):  
Diffusion Coefficient ◽  
Physical Interpretation ◽  
Anisotropic Diffusion ◽  
Scattered Light ◽  
Intermolecular Forces ◽  
Gaseous Hydrogen ◽  
Experimental Results ◽  
Scattering Angle ◽  
Collision Model

The diffusion coefficient characterizing the Dicke narrowing of the rotational Raman lines, in general, depends on the polarizations of the incident and scattered light and on the scattering angle. Experimental results for the anisotropic diffusion coefficient are presented for 90° scattering and vv and vh polarizations of the S0(1) line in gaseous hydrogen. The physical interpretation of the observed anisotropy is given with the help of a simple collision model.

Experimental analysis of crack evolution in concrete by the acoustic emission technique

2015 ◽  
Author(s):  
J. Saliba ◽  
A. Loukili ◽  
J.P. Regoin ◽  
D. Grégoire ◽  
L. Verdon ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fracture Process ◽  
Process Zone ◽  
Mouth Opening ◽  
Acoustic Emissions ◽  
Plain Concrete ◽  
Crack Mouth Opening Displacement ◽  
Notch Depth ◽  
Opening Displacement ◽  
Magnitude Distribution

The fracture process zone (FPZ) was investigated on unnotched and notched beams with different notch depths. Three point bending tests were realized on plain concrete under crack mouth opening displacement (CMOD) control. Crack growth was monitored by applying the acoustic emission (AE) technique. In order to improve our understanding of the FPZ, the width and length of the FPZ were followed based on the AE source locations maps and several AE parameters were studied during the entire loading process. The bvalue analysis, defined as the log-linear slope of the frequency-magnitude distribution of acoustic emissions, was also carried out to describe quantitatively the influence of the relative notch depth on the fracture process. The results show that the number of AE hits increased with the decrease of the relative notch depth and an important AE energy dissipation was observed at the crack initiation in unnotched beams. In addition, the relative notch depth influenced the AE characteristics, the process of crack propagation, and the brittleness of concrete.

scholarly journals Acoustic Emission in Snow at Constant Rates of Deformation

1973 ◽  
Vol 12 (64) ◽  
pp. 144-146 ◽  
Author(s):  
W. F. St. Lawrence ◽  
T. E. Lang ◽  
R.L. Brown ◽  
C. C. Bradley
Keyword(s):  
Acoustic Emission ◽  
Brittle Fracture ◽  
Uniaxial Compression ◽  
Laboratory Experiments ◽  
Acoustic Emissions ◽  
Snow Sample ◽  
Frequency Range ◽  
Snow Samples

AbstractAcoustic emissions in the audio spectrum are reported from observations of laboratory experiments conducted on snow samples in uniaxial compression. A number of tests show the pattern of acoustic emissions to be a function of the rate of deformation. Over the frequency range 20 to 7 000 Hz acoustic emissions are associated with rates of deformation corresponding to brittle fracture of the snow sample. Though probably present, no acoustic emissions were detected from samples deforming plastically.

Sign in / Sign up

Export Citation Format

Share Document