Güralp Systems is now able to offer the ARTeMIS software suite, developed by Structural Vibration Solutions, for applications in construction and civil engineering.
Using ARTeMIS Extractor with Güralp Systems CMG-5T and CMG-5U acceleration sensors, engineers have access to a complete modal analysis environment.
ARTeMIS
Natural-input modal analysis is a method of deriving the normal modes of vibration of a structure directly from the random impulses which occur naturally owing to ground motion and human activity.
Using natural-input modal analysis, engineers do not need to use impact hammers or any artificial vibration source to determine the characteristics of a structure. Not only does this make the experiment easier to carry out, but it completely removes the dependency on accurate measurements of the input signal.
Because data can be recorded and normal modes calculated in situ, structures in use can be monitored for any changes in their vibration characteristics which might indicate fatigue or other defects.
Natural-input modal analysis can also produce better results than traditional analysis: because natural ground motions arrive at the structure from all directions, rather than a single direction, closely-spaced and repeated vibration modes can be distinguished.
For more information, see SVS's introduction to NIMA.
A CMG-5T in place.
Broadband accelerometers, such as the CMG-5T, are ideal for natural-input modal analysis applications with ARTeMIS.
Ambient ground vibrations span a much wider range of amplitudes than those produced with shaking equipment or impact hammers. A sensor with low self-noise and high dynamic range is essential to detect and measure these vibrations.
CMG-5 instruments have dynamic range over 145 dB in the long period, and over 127 dB over the entire passband.
Random vibrations have complex structure over a large range of frequencies. To capture these vibrations, a sensor needs to have high linearity, and a flat response over a wide passband. Spurious modes of resonance must be kept to a minimum.
CMG-5 instruments have linearity of 0.1 % and no spurious resonances below 450 Hz.
The instrument must be easily installable, with secure mountings to maximize coupling to the building and eliminate interface resonance.
The CMG-5T Compact is under 125 mm in diameter and can be securely fixed to any surface with a single fixing bolt. Digital CMG-5TD sensors can be supplied with a mounting plate for installation.
For monitoring experiments, instruments need to retain their response characteristics over a long period of time. Multiple instruments should have similar response profiles for greater flexibility in installation and ease of processing.
The response of a broadband feedback instrument is determined entirely by its electronic components. At Güralp Systems every instrument is calibrated to ensure its response is identical to the published values.
Digital output from the instruments should be easy to convert to formats used by ARTeMIS.
All Güralp Systems instruments use the compact GCF format for digital output, which can be easily converted to UFF using our free Scream! acquisition and monitoring software.
DM24S12AMS
Güralp Systems have pioneered the use of redeployable multi-instrument arrays with the DM24S12AMS acquisition and monitoring system.
This unit acts as a data hub for small- to medium-size modal analysis deployments. Up to 12 CMG-5U uniaxial sensors, and up to 6 additional CMG-5TD digital instruments, can be connected to the DM24S12AMS simultaneously. The system has been used in a variety of deployments, from office buildings to wind farms.
An on-board laptop PC running Scream! gathers data from all the attached instruments. and displays it for monitoring purposes.
The DM24S12AMS can now be ordered with ARTeMIS already installed and configured for immediate use, minimizing the time and costs of setting up the system.