º£½ÇÉçÇø

Our centrifuge and structural testing experiments are supported by a flexible data acquisition (DAQ) and control infrastructure built around National Instruments (NI) PXI/SCXI hardware and an MTS Structural Testing System (STS). Together, these systems allow us to acquire high-quality data from large numbers of sensors, synchronize measurements with actuator commands, and tailor signal conditioning to the specific needs of each project.

At the core of the NI system is a PXI chassis with an embedded controller, which effectively acts as a ruggedized PC dedicated to DAQ and control. A suite of plug-in NI modules provides high-resolution analog input and output channels that can be configured for a variety of sensor types, including strain gauges, LVDTs, thermocouples, accelerometers, pressure transducers, and general voltage signals. The PXI chassis can be linked to one or more SCXI chassis, which house additional sensor-specific modules for strain, displacement, and temperature. These SCXI modules offer built-in bridge completion, programmable excitation, gain, filtering, and isolation, allowing us to handle everything from low-level millivolt bridge signals to higher-voltage transducers within the same integrated system. All NI hardware is controlled through LabVIEW, where we implement custom interfaces for real-time monitoring, closed-loop control, and on-the-fly calibration.

The MTS STS DAQ system complements the NI hardware and is tightly integrated with our servo-hydraulic actuators and load frames. A distributed network of junction boxes and dedicated cabling allows strain gauges, LVDTs, encoders, and accelerometers to be connected anywhere across the strong floor and centrifuge bay, with signals routed back to the MTS controller for conditioning and logging. For tests that require both sophisticated control (e.g., multi-axis loading protocols) and extensive sensor coverage, we can link the NI PXI system to the MTS controller via a fiber-optic interface, effectively combining the channel capacity of both platforms into a single synchronized experiment.

To support this DAQ backbone, the lab maintains a broad inventory of instrumentation suitable for geotechnical and structural applications. Available sensors include linear displacement transducers spanning sub-millimeter to multi-inch ranges, high-capacity and low-capacity load cells for shear and axial force measurement, encoders for long-stroke displacement tracking, high- and low-g accelerometers for dynamic response monitoring, and specialized extensometers for measuring localized strains. Shielded cabling, completion boxes, and terminal blocks are configured so that visiting users can plug in new sensors with minimal effort, and lab staff routinely assist with connector fabrication, wiring, and basic calibration checks.

Because the NI and MTS systems are modular, we can scale from small component-level tests with a handful of channels to large-scale centrifuge or structural experiments with dozens of strain, displacement, acceleration, and pressure measurements running concurrently. This flexibility, combined with custom LabVIEW interfaces and MTS control software, enables precise, repeatable, and well-documented measurements across the full range of CIEST research activities.

View More Details