Influence of small temperature variations on the ultrasonic velocity in concrete

Niederleithinger, Ernst; Wunderlich, Carolin

doi:10.1063/1.4789074

Cited by 37 publications

(35 citation statements)

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“…Unfortunately, the high sensitivity of coda waves also means that such methods are very susceptible to EOVs. 14,15 Some prior studies have used a reference specimen to compensate for measurement fluctuations in CWI measurements caused by temperature variations. 16,17 The reference specimen was subjected to the same temperature variations as the test specimen, but was not subjected to any loads.…”

Section: Introductionmentioning

confidence: 99%

Detecting damage events in concrete using diffuse ultrasound structural health monitoring during strong environmental variations

Fröjd

Ulriksen

2017

Structural Health Monitoring

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Diffuse ultrasonic wave measurements used in structural health monitoring applications can detect damage in concrete. However, the accuracy is very susceptible to environmental variations. In this study, a large concrete floor slab was monitored using diffuse wave fields that were generated by continuous-wave transmissions between ultrasonic transducers. The slab was monitored for several weeks while being subjected to changes in environmental conditions. Subsequently, it was damaged using impact hits, resulting in centimeter-scale cracking. The variations caused by the environment masked the effects of the damage in the measurements. To address this issue, the Mahalanobis distance was used to distinguish between the influence of the damage and the influence of the environmental variations. The Mahalanobis model uses amplitude and phase measurements of continuous waves at a set of different frequencies as inputs. A moving window approach was applied to the baseline data set to account for slow trends. This study shows that this technique greatly suppresses most of the variations caused by environmental conditions. All damage events in our data set have been detected.

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Section: Introductionmentioning

confidence: 99%

Detecting damage events in concrete using diffuse ultrasound structural health monitoring during strong environmental variations

Fröjd

Ulriksen

2017

Structural Health Monitoring

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“…The achieved sensitivity is so strong that a single change on one scatterer among thousands of others can be detected. Small relative velocity changes, of the order of 10 −5 , have also been measured using a technique based on the diffuse part of acoustic records [3,4] or the late part of seismograms, the seismic coda [5,6]. These results have been obtained by measuring the time shifts between waveforms that maximize their correlations.…”

Section: Introductionmentioning

confidence: 99%

Local time in diffusive media and applications to imaging

Rossetto

2013

Phys. Rev. E

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Local time is the measure of how much time a random walk has visited a given position. In multiple scattering media, where waves are diffuse, local time measures the sensitivity of the waves to the local medium's properties. Local variations of absorption, velocity and scattering between two measurements yield variations in the wave field. These variations are proportionnal to the local time of the volume where the change happened and the amplitude of variation. The wave field variations are measured using correlations and can be used as input in a inversion algorithm to produce variation maps. The present article gives the expression of the local time in dimensions one, two and three and an expression of its fluctuations, in order to perform such inversions and estimate their accuracy.

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“…The results show, that subtle changes in the concrete can be monitored with a sensibility (in terms of velocity change) up to 2*10 -5 . Details of the experiments are described in [11].…”

Section: Monitoring Subtle Changes In Concretementioning

confidence: 99%

Innovative Ultrasonic Techniques for Inspection and Monitoring of Large Concrete Structures

Wiggenhauser

Niederleithinger

2013

EPJ Web of Conferences

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Abstract. Ultrasonic echo and transmission techniques are used in civil engineering on a regular basis. New sensors and data processing techniques have lead to many new applications in the structural investigation as well as quality control. But concrete structures in the nuclear sector have special features and parameters, which pose problems for the methods and instrumentation currently available, e.g. extreme thickness, dense reinforcement, steel liners or special materials. Several innovative ultrasonic techniques have been developed to deal with these issues at least partly in lab experiments and pilot studies. Modern imaging techniques as multi-offset SAFT have been used e. g. to map delaminations. Thick concrete walls have successfully been inspected, partly through a steel liner. Embedded ultrasonic sensors have been designed which will be used in monitoring networks of large concrete structures above and below ground. In addition, sensitive mathematical methods as coda wave interferometry have been successfully evaluated to detect subtle changes in material properties. Examples of measurements and data evaluation are presented.

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Influence of small temperature variations on the ultrasonic velocity in concrete

Cited by 37 publications

References 0 publications

Detecting damage events in concrete using diffuse ultrasound structural health monitoring during strong environmental variations

Detecting damage events in concrete using diffuse ultrasound structural health monitoring during strong environmental variations

Local time in diffusive media and applications to imaging

Innovative Ultrasonic Techniques for Inspection and Monitoring of Large Concrete Structures

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