October 9th, 2010, NEES and PEER 2010 Annual Meetings
Site Operations Manager, NEES@UCLA This section gives a general overview of sensors, instrumentation, and data acquisition systems. Topics discussed in this section include: (1) what kinds of standard sensors are available at the NEES Equipment Sites, (2) how to select and specify sensors for an experiment, and (3) how to select and setup a Data Acquisition System (DAS) for different types of measurements.
|Presentation (PPT, 9.6MB)||Video part 1 (QuickTime MOV, 111MB)||Video part 2 (MOV, 70MB)||YouTube part 1||YouTube part 2|
Site Operations Manager, NEES@UCDavis NEES experimental facilities include tremendous resources for researchers to use in their experiments. Sites may offer hundreds of sensors, high speed video imaging systems, and new sensor technologies. The natural tendency for a new researcher is to want to try everything. But an effective experiment design is limited. The researcher should first clearly identify the mechanisms of interest--i.e., what question are we trying solve? Or what is it that we don't know? Experiment design begins with identifying what we are trying to learn, and matching that to the resources available. In this session we will discuss instrumentation for experiments, including how to set up your experiment; what you might include and what you should not include; and some limitations on what you can reasonably expect to be able to accurately monitor.
|Video (MOV, 142MB)||YouTube link|
Instrumentation Engineer, NEES@Minnesota Traditional instrumentation capabilities are limited to measurements in one or two degrees of freedom. The Nikon Metrology K600 Krypton camera is able to measure a point in three dimensions. The measurement system is based on three linear CCD cameras that detect a series of infrared LEDs in space and use triangulation to determine their 3D position. The presentation will discuss the features and capabilities of the system, how the system can be used in research projects, and the work being done at the University of Minnesota MAST Laboratory to create a visualization tool to view the Krypton data using RDV.
|Presentation (PPT, 5.6MB)||Video (MOV, 59MB)||YouTube link|
Site Operations Manager, NEES@RPI Sensors and transducers are vital components of geotechnical centrifuge testing. They need to be minimally invasive while producing accurate and repeatable data. Traditional sensors, e.g. accelerometers and strain gages, produce one-dimensional data streams that can be monitored and recorded using widely available and interchangeable systems. Advanced sensing techniques provide additional methods for system identification and acquiring experimental data. NEES@RPI has implemented non-traditional systems that complement traditional sensors. These include an in-flight high-speed camera and target tracking system for dynamic testing; and tactile sensors that measure 2-D soil pressure. The high-speed camera captures the motion of targets installed on the surface of centrifuge models. Motion tracking software is used to post-process video and determines the displacement of targets on the surface of a centrifuge model. Tactile pressure sensors are flexible sheets that are specifically designed to be minimally disruptive to a true pressure pattern. A tactile sensor contains a matrix of smaller sensors, individually referred to as sensels, which measure the change in resistance in response to an applied load. Pressure, force, and the center of force may be obtained through proprietary data acquisition hardware and software. In centrifuge modeling tests, tactile pressure sensors are used to measure the soil pressure on buried structures and obtain the at-rest lateral earth pressure for a model soil.
|Presentation (PPT, 2.7MB)||Video (MOV, 217MB)||YouTube link|
|Additional video: Non-Traditional Sensors in Geotechnical Centrifuge Models||Video (MOV, 89MB)||YouTube link|
Site Operations Manager, NEES@UTexas It is a stressful situation when something doesn't work during laboratory or field testing. To keep up with the schedule, one often rushes to fix the problem. However, if the problem is not resolved after 2 or 3 attempts, it can cause frustration. From the past experience, we found taking a two minute break can actually speed up the debugging process. As in debugging software programs, the keyword in debugging laboratory and field measurements is systematic. Three techniques are discussed in this section to serve as a starting point. These three debugging techniques are: (1) modulated debugging, (2) checking the voltage along the line, and (3) checking the resistance along the line. A potentiometer type displacement sensor is used as an example in the presentation to illustrate these techniques. A faulty load cell measurement circuit will be made available for practice in the hands-on section.
|Presentation (PPT, 401KB)||Video (MOV, 51MB)||YouTube link|