Experimental Time Domain Reflectometry (TDR) data obtained from the field are compared with numerical simulations using a finite-difference solution of the transmission line equations. The model simulates transmission of a voltage pulse along a lossy coaxial cable where deformities on the cable, such as crimps and shears, are represented by...
Miniaturized, wireless instrumentation is now a reality and this thesis describes development of such a system to monitor crack response. Comparison of environmental (long-term) and blast-induced (dynamic) crack width changes in residential structures has lead to a new approach to monitoring and controlling construction vibrations. In wireless systems transducer power...
The thesis describes the second phase of development of the Autonomous Crack Comparometer (ACC) system to incorporate measurements of ground motions and add several changes in the autonomous operation. In order to obtain the ground motion and air blast data, four additional transducers have been added. There are now a...
All structures have cosmetic cracks, which have no influence on structural integrity and usually remain unremarked until the structure’s occupants sense ground vibrations. Such vibrations are often associated with engineering activity, but are rarely responsible for cracks. However, this is difficult to prove without scientific basis. Automated Crack Monitoring (ACM)...
Autonomous Crack Monitoring (ACM) and Autonomous Crack Propagation Sensing (ACPS) are two types of structural health monitoring in which characteristics of cracks are recorded over long periods of time. ACM seeks to correlate changes in widths of cosmetic cracks in structures to nearby blasting or construction vibration activity for the...