Areas that are difficult to access and inspect can be effectively monitored for crack initiation and growth by using acoustic emission (AE) technology. For structures loaded randomly, such as offshore platforms, continuous monitoring is necessary. In addition to AE, the acquisition of dynamic strain data gives essential information on structural behaviour, helps with life prediction, and aids analysis in the case that cracking is suspected. Physical Acoustics structural monitoring expertise includes both metals, and reinforced concrete, and applications as diverse as offshore platforms, bridges, nuclear reactors, and process plant.

 

 

Good data begins with Physical Acoustics data acquisition systems, Physical Acoustics is the world leader in AE technology with ~85% market share*, our systems make extensive use of DSP's (digital signal processors) and FPGA's to process data at high speed in real-time (>20MB/sec/channel) and avoid "data overload" downstream. A typical 40 channel system has DSP processing power of 3GFLOPS (3 billion 32-bit floating point operations per second, in addition to the real-time FPGA's). Strain data is acquired "in-phase" at high resolution so it is useable for dynamic structural analysis, intelligent acquisition acquires fast scan transients whenever the strain exceeds a set threshold, "slow strain" data is used to generate strain range histograms and time histories for improving fatigue predictions.

 

The high-density electronics are manufactured in-house using the latest automated surface-mount technology. System measurement resolution, speed and accuracy is the best available in the market. Physical Acoustics has ensured backwards compatibility and support for its customers systems and data for over 20 years, one of the main reasons for its continued market dominance. Intrinsically safe, the systems are remotely monitored and controlled via network, eliminating the need for offshore system expertise or regular visits. In common with other PAC remote structural monitoring applications, a networked system (Win 2000 Pro is the standard operating system used) may automatically generate results, upload them to a web-site, and provide near real-time customer access. Field experience has demonstrated typical uptimes of >99%.

 

Physical Acoustics works with the customer and other experienced professional partners to provide a total system solution meeting customer requirements. Installation time is minimised by extensive advance planning.

 

Acoustic emission results provide detection and location of active crack growth in steel and RC, for the areas monitored. If cracks are identified the extent of their growth can be monitored by triangulation. Strain data provides time histories, strain range distributions, and high scan rate "strain transient" files whenever very high strains are detected. Low-Frequency "seismic" Accelerometers and LVDT's may also be used for analysing global dynamic movement. Other sensing inputs are easily integrated into the systems.

 

Physical Acoustics will provide the necessary technical support, and if necessary verification trials, to ensure the solution meets customer requirements. In many instances the data from our hundreds of man years research experience will suffice.