TY - JOUR A1 - Wolf, Julia A1 - Pirskawetz, Stephan A1 - Zang, A. T1 - Detection of crack propagation in concrete with embedded ultrasonic sensors JF - Engineering fracture mechanics N2 - This study evaluates the sensitivity of embedded ultrasonic sensors to detect propagating cracks within concrete. Because of the sensors constant coupling to the medium, highly sensitive data analysis techniques, such as the correlation between signals and their attenuation, are applied to detect changes in the signal due to propagating cracks. The accuracy of the detected onset of the crack is evaluated with the nondestructive testing methods acoustic emission and Digital Image Correlation. It shows that with embedded ultrasonic sensors crack propagation can be detected before it is visible on the surface of the concrete. KW - Embedded sensors KW - Ultrasound KW - Acoustic emission KW - Concrete KW - Cracks PY - 2015 DO - https://doi.org/10.1016/j.engfracmech.2015.07.058 SN - 0013-7944 SN - 1873-7315 VL - 146 SP - 161 EP - 171 PB - Elsevier Science CY - Kidlington AN - OPUS4-34479 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Niederleithinger, Ernst A1 - Wolf, Julia A1 - Mielentz, Frank A1 - Wiggenhauser, Herbert A1 - Pirskawetz, Stephan T1 - Embedded ultrasonic transducers for active and passive concrete monitoring JF - Sensors N2 - Recently developed new transducers for ultrasonic transmission, which can be embedded right into concrete, are now used for non-destructive permanent monitoring of concrete. They can be installed during construction or thereafter. Large volumes of concrete can be monitored for changes of material properties by a limited number of transducers. The transducer design, the main properties as well as installation procedures are presented. It is shown that compressional waves with a central frequency of 62 kHz are mainly generated around the transducer's axis. The transducer can be used as a transmitter or receiver. Application examples demonstrate that the transducers can be used to monitor concrete conditions parameters (stress, temperature, …) as well as damages in an early state or the detection of acoustic events (e.g., crack opening). Besides application in civil engineering our setups can also be used for model studies in geosciences. KW - Ultrasound KW - Transmission KW - Concrete KW - Damages KW - Cracks KW - Stress KW - Monitoring KW - Acoustic emission KW - Transducers KW - Coda wave interferometry PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345632 DO - https://doi.org/10.3390/s150509756 SN - 1424-8220 VL - 15 IS - 5 SP - 9756 EP - 9772 PB - MDPI CY - Basel AN - OPUS4-34563 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -