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Laser optic vibration sensing for the inspection of bonds in the orbiter thermal protection tiles
Non-Destructive Testing, Proceedings of the 4th European Conference, London (United Kingdom), 13-17 Sep. 1987. Vol. 4, pp. 2684-2693. Edited by J.M. Farley and R.W. Nichols. Pergamon Press. 1988 Due to their means of operation helicopters arc significantly more susceptible to serious mechanical failures than are fixed-wing aircraft. Such failures may have catastrophic results e.g. in North Sea Oil-rig operations. Over the last few years a wide range of predictive techniques have bccn developed by Government Agencies and the Helicopter Industry to monitor the health of critical components in order to take remedial action before failure occurs. More recently, microprocessor-based monitoring systems have been developed which quantify damage parameters in real-time and give an indication to the flight or ground crew of the current health of the components monitored. These systems are currently at the prototype stage and are undergoing evaluation with a view to manufacturing units suitable for installation in a wide range of hclicopter types. 40398
Milne, R.
Artificial intelligence for vibration based health monitoring Non-Destructive Testing, Proceedings of the 4th European Conference, London (United Kingdom), 13-17 Sep. 1987. Vol. 4, pp. 2678-2683. Edited by J.M. Farley and R.W. Nichols. Pergamon Press, 1988 Artificial Intelligence provides many powerful techniques to manipulate large amounts of information both about a particular domain as well as expert information. This expert information could be a wide range of facts, figures, descriptions and other knowledge that an expert normally uses in solving difficult problems. Non-Destructive Testing is becoming increasingly important. The complexity of Non-Destructive Testing tasks is also becoming increasingly difficult. One clear trend for the future is the marriage between Artificial Intelligence and N.D.T. To assist with vibration based mechanical health monitoring, the system called Violet has been developed. This system serves as an intelligent front end to a spectrum analyser and also provides intelligent interpretation of the spectral information. Violet is a very powerful toolkit for building interpretations of spectral data. Its initial application is health monitoring for helicopter rotor blades. The system also provides extensive trending and curve fitting facilities. 40397
Hills, P. W.
Modern predictive maintenance systems for monitoring vibration on rotating machinery Non-Destructive Testing, Proceedings of the 4th European Conference, London (United Kingdom), 13-17 Sep. 1987. Vol. 4, pp. 2667-2677. Edited by J.M. Farley and R.W. Nichols. Pergamon Press, 1988 Introducing a vibration based predictive maintenance system for monitoring the condition of rotating machinery gives both production and maintenance personnel lead time to avoid unscheduled plant outage. To be fully effective, systematic data collection, rapid evaluation and simple reporting methods are required. This paper outlines the maintenance strategy for selecting stateof-the-art predictive maintenance systems and then briefly describes the three main categories in current use. Periodic manual monitoring, automatic survcillance and continuous monitoring may be operated as individual or integrated plant-wide systems to provide maintenance managers with essential machinery condition information. 40200
Russell, S.S.; Lin, S.S.; Henneki, E.G.
Vibrothermographic NDE of fiherous composites Review of Progress in Quantitative Nondestructive Evaluation, Williamsburg, Virginia (United States), 22-26 Jun. 1987. Vol. 7B, pp. 1101-1108. Edited by D.D. T h o m p s o n and D.E. Chimenti, Plenum Press, 1988. Vibrothermography refers to the process of mapping the temperaturcs on the surface of a component while the component is undergoing forced mechanical vibration. Damaged zones in a polymeric fiber reinforced composite more efficiently convert kinetic energy to heat. Hence, at certain frequencies. delaminations and other damage appear to a scanning infrared camera as hot zones. This discussion of Vibrothermography will highlight the capabilities, advantages and limitations of using Vibrothermography as a nondestructive evaluation tool for fiber reinforced composites. Also, the frequency dependence of exciting dclaminations will be examined within the framework of a Raleigh-Ritz model of a delamination. The predictions of this model arc compared to laboratory results. Several trial investigations are presented. 40190
Barna, B.A.; Allemeier, R.T.; Rodiguez, J.G.
Laser optic vibration sensing for the inspection of bonds in the orbiter thermal protection tiles Review of Progress in Quantitative Nondestructive Evaluation, Williamsburg, Virginia (United States), 22-26 Jun. 1987. Vol. 7B, pp. 1227-1236. Edited by D.D. T h o m p s o n and D.E. Chimenti, Plenum Press, 1988. This paper describes the use of a noncontacting acousto-optie sensor for the detection of bonding flaws in complex composite structures, in the inspection of the complex, multitayer bond of the silica fiber composite thermal protection tiles for the Space Shuttle Orbiter. The approach described is used to sense submicron vibration displacements of the tile surface using a frequency stabilized helium-neon laser, and the signal processing applied using a computerized NDE workstation. The noncontacting laser acoustic sensor allows a rapid measurement that does not perturb the dynamic response and does not
104
damage the surface of interest. In addition, a coherent light imaging technique fi)r real- time visualization of the tile vibration modes (speckle interfclomctry) was used to guide the single point vibration measurements and study Ihe vibration mode shapes and their behavior as the bond was degraded 40003
Lundgaard, B.
Using transducers for machinery fault detection Sensors, Vol. 5, No. 11, pp. 28-31 (Nov. 1988) A variety of transducer arrangements can be used to detect machinery faults through vibration analysis. The results of a survey conducted in 1987 on the USS Constellation are examined in this paper, in which 379 machines were covered. Machines with one or three or more positions have been excluded here in order to simplify the statistical analysis, leaving 262 machines with two transducer positions. The transducers used incorporated three-channel accclerometers. The vibration signatures from the two triaxial transducer arrays yielded 97 repair recommendations. To investigate the effi:ct of reducing the number of transducers, the data wcrc rcanalyzed for various combinations of transducer positions. The results show a consequent loss in diagnostic accuracy. 39857
Rudnitskii, V.A.; Nedbalskii, 1.1.
Dynamic inspection of hardness in the self-oscillatory regime Soviet Journal of Nondestructive Testing, Vol. 24, No. 1, pp. 20-25 (Jan. 1988) The mcthod of inspecting hardness using a vibroimpact transducer working in the self-oscillatory regime is described analytically and graphically. The design of the transducer and of the device is examined. 39796
Fried. Krupp Gesellschafi
Method and apparatus for monitoring machine parts U.S. Patent No. 4,758,964 (19 Jul. 1988) Vibration testing is the basis of this method and apparatus for monitoring machine parts for wear. Vibrations arc detected and converted into analog electrical values. Output signals are analyzed according to evaluation criteria. The device includes a means of comparing output to desired state signals, it emits a signal whenever the desired threshold value is exceeded. A more complex memory device provides frequency and peak value analyses.
Gordon, A.L.; Armour, I.A.; Glanville, R.; Malcolm, G.J.; Wright, D. G.
39767
Holographic inspection of nuclear plant Proceedings of the International Conference on Remote Techniques for Inspection and Refurbishment of Nuclear Plant, Stratfordupon-Avon (United Kingdom), 28 November - 1 December 1988, pp. 87-95. The British Nuclear Energy Society, London. The high resolution, enormous depth of field and high tolerance to radiation of holography mean that it has great potential as an inspection tool in the nuclear industry. In addition, the ability of double-pulse holography to yield detailed information on vibration over the whole field of both large and small structures provides measurements that often cannot be obtained in any other way. This paper reviews the development of equipment for the holographic inspection of nuclear fuel elements; a portable holocamera for use inside reactors; and the application of holographic techniques for vibration measurements in a nuclear power station. 39740
Kosarev, L.I.; Kuzelev, N.R.; Yumashev, V.M.; Shtan' A.S.
Application of computer-aided radiation tomography to quality inspection of vibrocompacted fuel elements Soviet Atomic Energy, Vol. 62, No. 1, pp. 14-19 (Jul. 1987) Computer tomography can be used to extend the service life of power reactor fucl elements. Automated inspection systems using computers have lead to increased quality of fuel elements. Fuel distribution in vibrocompaeted fucl cores in elements can be detailed quantitatively with this method. 39692
Astridge, D.G.
HUM - Health and usage monitoring of helicopter mechanical systems British Journal of Nondestructive Testing, Vol. 30, No. 6, pp. 403-408 (Nov. 1988) Advances in monitoring technology over the last decade offer substantial improvements in flight safety and in cost of ownership of helicopters. This paper reviews many of these advances seen from the viewpoint of a helicopter manufacturer involved in Health and Usage Monitoring (HUM) development and implementation on its own products and collaborative ventures. The topics covered include gearbox diagnostics and torque monitoring, engine diagnostics and usage monitoring, and rotor system/airframe vibration monitoring. The results of nearly four years experience with advanced gearbox diagnostics systems on the Westland 30 helicopter in commercial operation are given, backed up by extensive gearbox rig tests to component failure. 39573
Prudko, N.1.
Non-destructive testing of piezoelectric vibrator by new admittance method Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 3, pp. 1870-1873. Pergamon Press, 3173 pp. (1988) Coefficients defining the energy dissipation are sensitive indices of the quality of piezoelectric vibrators. An improved model of piezoelectric vibrators which differs from Van Dyke classical model with a complete representation of various loss energy components is proposed. A new method by which real parts
NDT& E International April 1991
Milne, R.
Artificial intelligence for vibration based health monitoring Non-Destructive Testing, Proceedings of the 4th European Conference, London (United Kingdom), 13-17 Sep. 1987. Vol. 4, pp. 2678-2683. Edited by J.M. Farley and R.W. Nichols. Pergamon Press, 1988 Artificial Intelligence provides many powerful techniques to manipulate large amounts of information both about a particular domain as well as expert information. This expert information could be a wide range of facts, figures, descriptions and other knowledge that an expert normally uses in solving difficult problems. Non-Destructive Testing is becoming increasingly important. The complexity of Non-Destructive Testing tasks is also becoming increasingly difficult. One clear trend for the future is the marriage between Artificial Intelligence and N.D.T. To assist with vibration based mechanical health monitoring, the system called Violet has been developed. This system serves as an intelligent front end to a spectrum analyser and also provides intelligent interpretation of the spectral information. Violet is a very powerful toolkit for building interpretations of spectral data. Its initial application is health monitoring for helicopter rotor blades. The system also provides extensive trending and curve fitting facilities. 40397
Hills, P. W.
Modern predictive maintenance systems for monitoring vibration on rotating machinery Non-Destructive Testing, Proceedings of the 4th European Conference, London (United Kingdom), 13-17 Sep. 1987. Vol. 4, pp. 2667-2677. Edited by J.M. Farley and R.W. Nichols. Pergamon Press, 1988 Introducing a vibration based predictive maintenance system for monitoring the condition of rotating machinery gives both production and maintenance personnel lead time to avoid unscheduled plant outage. To be fully effective, systematic data collection, rapid evaluation and simple reporting methods are required. This paper outlines the maintenance strategy for selecting stateof-the-art predictive maintenance systems and then briefly describes the three main categories in current use. Periodic manual monitoring, automatic survcillance and continuous monitoring may be operated as individual or integrated plant-wide systems to provide maintenance managers with essential machinery condition information. 40200
Russell, S.S.; Lin, S.S.; Henneki, E.G.
Vibrothermographic NDE of fiherous composites Review of Progress in Quantitative Nondestructive Evaluation, Williamsburg, Virginia (United States), 22-26 Jun. 1987. Vol. 7B, pp. 1101-1108. Edited by D.D. T h o m p s o n and D.E. Chimenti, Plenum Press, 1988. Vibrothermography refers to the process of mapping the temperaturcs on the surface of a component while the component is undergoing forced mechanical vibration. Damaged zones in a polymeric fiber reinforced composite more efficiently convert kinetic energy to heat. Hence, at certain frequencies. delaminations and other damage appear to a scanning infrared camera as hot zones. This discussion of Vibrothermography will highlight the capabilities, advantages and limitations of using Vibrothermography as a nondestructive evaluation tool for fiber reinforced composites. Also, the frequency dependence of exciting dclaminations will be examined within the framework of a Raleigh-Ritz model of a delamination. The predictions of this model arc compared to laboratory results. Several trial investigations are presented. 40190
Barna, B.A.; Allemeier, R.T.; Rodiguez, J.G.
Laser optic vibration sensing for the inspection of bonds in the orbiter thermal protection tiles Review of Progress in Quantitative Nondestructive Evaluation, Williamsburg, Virginia (United States), 22-26 Jun. 1987. Vol. 7B, pp. 1227-1236. Edited by D.D. T h o m p s o n and D.E. Chimenti, Plenum Press, 1988. This paper describes the use of a noncontacting acousto-optie sensor for the detection of bonding flaws in complex composite structures, in the inspection of the complex, multitayer bond of the silica fiber composite thermal protection tiles for the Space Shuttle Orbiter. The approach described is used to sense submicron vibration displacements of the tile surface using a frequency stabilized helium-neon laser, and the signal processing applied using a computerized NDE workstation. The noncontacting laser acoustic sensor allows a rapid measurement that does not perturb the dynamic response and does not
104
damage the surface of interest. In addition, a coherent light imaging technique fi)r real- time visualization of the tile vibration modes (speckle interfclomctry) was used to guide the single point vibration measurements and study Ihe vibration mode shapes and their behavior as the bond was degraded 40003
Lundgaard, B.
Using transducers for machinery fault detection Sensors, Vol. 5, No. 11, pp. 28-31 (Nov. 1988) A variety of transducer arrangements can be used to detect machinery faults through vibration analysis. The results of a survey conducted in 1987 on the USS Constellation are examined in this paper, in which 379 machines were covered. Machines with one or three or more positions have been excluded here in order to simplify the statistical analysis, leaving 262 machines with two transducer positions. The transducers used incorporated three-channel accclerometers. The vibration signatures from the two triaxial transducer arrays yielded 97 repair recommendations. To investigate the effi:ct of reducing the number of transducers, the data wcrc rcanalyzed for various combinations of transducer positions. The results show a consequent loss in diagnostic accuracy. 39857
Rudnitskii, V.A.; Nedbalskii, 1.1.
Dynamic inspection of hardness in the self-oscillatory regime Soviet Journal of Nondestructive Testing, Vol. 24, No. 1, pp. 20-25 (Jan. 1988) The mcthod of inspecting hardness using a vibroimpact transducer working in the self-oscillatory regime is described analytically and graphically. The design of the transducer and of the device is examined. 39796
Fried. Krupp Gesellschafi
Method and apparatus for monitoring machine parts U.S. Patent No. 4,758,964 (19 Jul. 1988) Vibration testing is the basis of this method and apparatus for monitoring machine parts for wear. Vibrations arc detected and converted into analog electrical values. Output signals are analyzed according to evaluation criteria. The device includes a means of comparing output to desired state signals, it emits a signal whenever the desired threshold value is exceeded. A more complex memory device provides frequency and peak value analyses.
Gordon, A.L.; Armour, I.A.; Glanville, R.; Malcolm, G.J.; Wright, D. G.
39767
Holographic inspection of nuclear plant Proceedings of the International Conference on Remote Techniques for Inspection and Refurbishment of Nuclear Plant, Stratfordupon-Avon (United Kingdom), 28 November - 1 December 1988, pp. 87-95. The British Nuclear Energy Society, London. The high resolution, enormous depth of field and high tolerance to radiation of holography mean that it has great potential as an inspection tool in the nuclear industry. In addition, the ability of double-pulse holography to yield detailed information on vibration over the whole field of both large and small structures provides measurements that often cannot be obtained in any other way. This paper reviews the development of equipment for the holographic inspection of nuclear fuel elements; a portable holocamera for use inside reactors; and the application of holographic techniques for vibration measurements in a nuclear power station. 39740
Kosarev, L.I.; Kuzelev, N.R.; Yumashev, V.M.; Shtan' A.S.
Application of computer-aided radiation tomography to quality inspection of vibrocompacted fuel elements Soviet Atomic Energy, Vol. 62, No. 1, pp. 14-19 (Jul. 1987) Computer tomography can be used to extend the service life of power reactor fucl elements. Automated inspection systems using computers have lead to increased quality of fuel elements. Fuel distribution in vibrocompaeted fucl cores in elements can be detailed quantitatively with this method. 39692
Astridge, D.G.
HUM - Health and usage monitoring of helicopter mechanical systems British Journal of Nondestructive Testing, Vol. 30, No. 6, pp. 403-408 (Nov. 1988) Advances in monitoring technology over the last decade offer substantial improvements in flight safety and in cost of ownership of helicopters. This paper reviews many of these advances seen from the viewpoint of a helicopter manufacturer involved in Health and Usage Monitoring (HUM) development and implementation on its own products and collaborative ventures. The topics covered include gearbox diagnostics and torque monitoring, engine diagnostics and usage monitoring, and rotor system/airframe vibration monitoring. The results of nearly four years experience with advanced gearbox diagnostics systems on the Westland 30 helicopter in commercial operation are given, backed up by extensive gearbox rig tests to component failure. 39573
Prudko, N.1.
Non-destructive testing of piezoelectric vibrator by new admittance method Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987. Vol. 3, pp. 1870-1873. Pergamon Press, 3173 pp. (1988) Coefficients defining the energy dissipation are sensitive indices of the quality of piezoelectric vibrators. An improved model of piezoelectric vibrators which differs from Van Dyke classical model with a complete representation of various loss energy components is proposed. A new method by which real parts
NDT& E International April 1991