Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Defect localisation in wood with low frequency ultrasonic echo technique
The use of low-frequency ultrasonic echo technology with longitudinal and transverse waves for the investigation of wooden construction components is described. Further more the different influences of the wood fibres on the sound velocity of the longitudinal and transversal waves is pointed out on the basis results of measurements. The efficiency of the ultrasonic echo technique is shown on wooden specimens. It is possible to use low frequency ultrasonic echo techniques successfully with longitudinal (100 kHz) and with transverse (55 kHz) waves on wood. So it is possible to detect the back walls of the specimens as well as the inserted cavities inside the structures. The relative results can be calibrated by measuring the dimension of the specimen on the area were it is possible to use drill resistance. So it is possible to check the thickness of a beam without cracks even though the back wall is not accessible. It is therefore possible to determine the dimensions and inner structure of large constructions. Detailed tests are only necessary in areas with no or an unexpectedly early echo from the back wall, because this can be a sign of damage. With a combination of the described procedures, damage can be examined rationally: The ultrasonic echo procedure can be used for the investigation of large areas. Thus areas with irregularities can be determined under certain conditions, such as accessibility, few cracks, and undamaged surfaces. The expansion of these areas can be examined exactly by X-ray and the position in depth and the kind of defects using drilling resistance. The present investigation shows that the ultrasonic echo technique has the capability to be utilized for the preservation of large wooden structures, e.g. monuments and historic buildings (frameworks, churches,...). The early detection of defects and their extend make it possible to precisely locate hidden damage that would normally only be discovered during restoration. The possibilities of discovering hidden damage before commencement of work permits a more precise estimation of costs, and therefore a more economic allocation of funds.
Defect localisation in wood with low frequency ultrasonic echo technique
The use of low-frequency ultrasonic echo technology with longitudinal and transverse waves for the investigation of wooden construction components is described. Further more the different influences of the wood fibres on the sound velocity of the longitudinal and transversal waves is pointed out on the basis results of measurements. The efficiency of the ultrasonic echo technique is shown on wooden specimens. It is possible to use low frequency ultrasonic echo techniques successfully with longitudinal (100 kHz) and with transverse (55 kHz) waves on wood. So it is possible to detect the back walls of the specimens as well as the inserted cavities inside the structures. The relative results can be calibrated by measuring the dimension of the specimen on the area were it is possible to use drill resistance. So it is possible to check the thickness of a beam without cracks even though the back wall is not accessible. It is therefore possible to determine the dimensions and inner structure of large constructions. Detailed tests are only necessary in areas with no or an unexpectedly early echo from the back wall, because this can be a sign of damage. With a combination of the described procedures, damage can be examined rationally: The ultrasonic echo procedure can be used for the investigation of large areas. Thus areas with irregularities can be determined under certain conditions, such as accessibility, few cracks, and undamaged surfaces. The expansion of these areas can be examined exactly by X-ray and the position in depth and the kind of defects using drilling resistance. The present investigation shows that the ultrasonic echo technique has the capability to be utilized for the preservation of large wooden structures, e.g. monuments and historic buildings (frameworks, churches,...). The early detection of defects and their extend make it possible to precisely locate hidden damage that would normally only be discovered during restoration. The possibilities of discovering hidden damage before commencement of work permits a more precise estimation of costs, and therefore a more economic allocation of funds.
Defect localisation in wood with low frequency ultrasonic echo technique
Fehlerortung in Holz mit niederfrequenter Ultraschall-Echotechnik
Hasenstab, A. (Autor:in) / Hillemeier, B. (Autor:in) / Krause, M. (Autor:in)
2005
6 Seiten, 14 Bilder, 1 Tabelle, 14 Quellen
Aufsatz (Konferenz)
Englisch
Ultrasonic Pulse-Echo Subwavelength Defect Detection Mechanism: Experiment and Simulation
| British Library Online Contents | 2003
Structure testing with ultrasonic-echo and impulse radar technique
| British Library Conference Proceedings | 2012
Inspection of concrete by ultrasonic pulse-echo-technique
| Tema Archiv | 1994
Diagnostic investigations of wooden structures using ultrasonic-echo technique
| British Library Conference Proceedings | 2008
Ultrasonic defectoscopy of concrete by means of pulse-echo technique
| Tema Archiv | 2002