Experimental Study on Recentering Behavior of Precompressed Polyurethane Springs
Young-Hun Ju1,2, Iman Mansouri3, Jong-Wan Hu1,2
1Department of Civil and Environmental Engineering, Incheon National University, Incheon 22012, Korea.
Materials (Basel, Switzerland)
|May 28, 2022
Summary
Polyurethane springs offer enhanced seismic resilience by utilizing smart material recentering properties. Controlling precompression strain in these springs effectively minimizes permanent deformation, improving structural safety.
Area of Science:
- Materials Science
- Civil Engineering
- Structural Engineering
Background:
- Traditional seismic design struggles with permanent deformation after plastic behavior under external loads.
- Smart materials offer recentering properties to overcome limitations in conventional seismic design.
- Polyurethane springs can have their recentering characteristics tuned by adjusting precompression strain.
Purpose of the Study:
- To investigate the compression and precompression behavior of polyurethane springs.
- To determine the relationship between design variables (compressive stiffness, specimen size, precompression strain) and spring performance.
- To establish an optimal precompression level to prevent residual strain and develop a predictive model for recentering force.
Main Methods:
- Fabrication of 160 polyurethane spring specimens with varying design variables.
- Cyclic loading tests to analyze compression and precompression behavior.
- Regression analysis to identify optimal precompression and model recentering force.
Main Results:
- A linear relationship was observed between maximum stress and maximum strain in the polyurethane springs.
- A strong linear correlation was found between precompression and recentering forces.
- The optimal precompression strain to avoid residual strain was determined.
Conclusions:
- Polyurethane springs, by controlling precompression strain, can effectively mitigate permanent deformation in seismic applications.
- A predictive model for recentering force was developed, based on the linear relationship with precompression.
- This research provides a method to enhance seismic design using tunable smart material properties.
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