Pseudodynamic Test Method for the MOST Experiment

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Pseudodynamic Test Method for the MOST Experiment
George E. Brown, Jr. Network for Earthquake
Engineering Simulation

• P. Benson Shing
• University of Colorado at Boulder

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Pseudodynamic Test Method
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Integration Schemes

• Central Difference
• Constant Average Acceleration
• a Method
• a-OS Method

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Advantages of a-OS Method

• Unconditionally stable implicit scheme
• No iteration is required for a nonlinear structure

Drawbacks

• Larger frequency distortion.
• Larger experimental error effect.

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a Method of Hilber, Hughes and Taylor
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a-OS Method
Predictor
Corrector
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Restoring Force Approximation
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Modified Equations of Motion
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Multi-Site Substructure Tests
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Multi-Site Substructure Tests
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Multi-Site Substructure Tests
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Implementation

• Compute predictor displacements .
• Impose on the test structures.
• Compute with the computation
  model.
• Measure and developed by
  the test structures.
• Solve the equations of motion for .
• Compute corrected displacement .

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Implementation

• Compute .
• Set i i 1 and go to Step 1.

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Real-Time Ramp Function Generation/Feedback
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Possible Improvement
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Error Correction
I-Modification - Introduces some damping effect
This could potentially lead to large artificial
damping.