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Utilization of moiré interferometry to study the strain distribution within multi-layer thermoplastic elastomers
Mao Wang1, Michael J Drews, Judy Wood
1School of Material Science and Engineering, Clemson University, South Carolina 29634, USA.
Journal of Biomaterials Science. Polymer Edition
|December 5, 2002
Summary
Soft elastomeric bearings show promise for reduced friction but can debond. Moiré interferometry successfully measured strain in these materials, revealing high shear stress points that may cause fatigue failure.
Area of Science:
- Materials Science
- Polymer Engineering
- Biomechanics
Background:
- Soft elastomeric bearings are explored as alternatives to ultra-high molecular weight polyethylene (UHMWPE) for improved lubrication and reduced friction.
- A key challenge is the stiffness mismatch between soft elastomeric layers and rigid substrates, causing high shear stress and debonding.
- Functionally modulus-graded materials are proposed to mitigate this stiffness mismatch.
Purpose of the Study:
- To investigate the application of moiré interferometry for analyzing strain distribution in multi-layer elastomeric materials.
- To model and study the behavior of functionally modulus-graded materials using elastomeric samples.
- To assess the suitability of moiré interferometry for low-modulus polymers exhibiting viscoelasticity.
Main Methods:
- Fabrication of multi-layer elastomeric samples as models for functionally modulus-graded materials.
- Application of moiré interferometry to measure strain distribution within and across material interfaces.
- Analysis of moiré patterns to understand deformation behavior under load, particularly in viscoelastic polymers.
Main Results:
- Moiré interferometry was successfully applied to low-modulus polymers with significant viscoelastic behavior.
- Analysis revealed compressive strain (epsilonx) and sideways displacement in the soft elastomeric material under the contact point.
- Maximum shear strain was observed at constrained deformation points, indicating potential sites for fatigue failure.
Conclusions:
- Moiré interferometry is a viable technique for studying strain in low-modulus elastomeric materials.
- Understanding strain distribution is crucial for predicting and preventing debonding and fatigue failure in elastomeric bearings.
- The findings provide insights into the mechanical behavior of graded elastomeric materials, relevant for advanced bearing design.