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Research

Current research focuses include:

  • Hybrid Testing of Large and Complex Structural Systems
  • Mixed Load and Displacement Control for Structural Testing
  • Smart Structures Technology
  • Virtual Structural Testing Laboratory (VSTL)

 
Hybrid Testing

Hybrid Testing (Hybrid Simulation) is an effective experimental method that combines laboratory experiment with numerical analysis. The experimental substructures are usually structural members that are difficult to model in numerical analysis, whereas the numerical substructures are those that can be modeled within a reasonable tolerance. Using the Hybrid Testing method, large and complex structural systems can be modeled using various experimental and numerical resources, dynamic response of such large and complex structural systems can be simulated, and critical structural components can be assessed at the systems level.
Mixed Load and Displacement Control
Structural members exhibit complex behavior under multi-directional loadings, such as shear, flexure, axial, and torsional loadings. For example, behavior of vertical structural members is susceptible to the influence of axial loads, which create a second-order effect (P-delta effect) under large deformation. To impose and measure mixed load and displacement boundary conditions on test specimen, control and data acquisition systems have to properly transform coordinates between Cartesian and actuator spaces, taking into account actuator kinematics and system geometry. The challenge is that mixed-mode commands cannot be explicitly decomposed into individual actuator displacement or force commands, due to cross-coupling between Cartesian and actuator spaces.
Smart Structures Technologies

Using Smart Structures Technologies (SST), including smart materials, smart actuation, smart damping, and smart sensing, the safety and integrity of civil structures can be enhanced in various ways. Among these enhancements are vibration and noise reduction, structure self-alignment, monitoring of structure conditions and environment, provision of security alerts, and damage detection. Furthermore, with emerging wireless sensor technology that provides on-board signal processing and communications networks, the potential of SST has become even higher. For practical applications of SST, more research is required for development, implementation, and verification of technologies.

Virtual Structural Testing Laboratory (VSTL)

Structural testing systems and facilities have advanced, and their capabilities have significantly improved. However, due to test complexity, even experienced system users can have difficulty validating their test results. The Virtual Structural Testing Laboratory (VSTL) aims to provide a virtual environment using advanced network and visualization tools through which users can learn fundamentals of controls, sensors, data acquisition, and signal processing. VSTL also covers a variety of structural testing methods, such as quasi-static, dynamic, hybrid (pseudo-dynamic), and effective-force testing.