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Viscoelastic Characterization of Soft Tissue-Mimicking Gelatin Phantoms using Indentation and Magnetic Resonance Elastography
Published on: May 10, 2022
Viscoelastic effects during loading play an integral role in soft tissue mechanics
Kevin L Troyer1, Donald J Estep, Christian M Puttlitz
1Department of Mechanical Engineering, Colorado State University, Fort Collins, CO 80523-1374, USA.
Acta Biomaterialia
|August 23, 2011
Summary
This study introduces a new method to accurately measure the viscoelastic properties of biological soft tissues during tensioning. The technique improves accuracy by accounting for relaxation during loading, crucial for understanding tissue mechanics.
Area of Science:
- Biomedical Engineering
- Materials Science
- Biomechanics
Background:
- Biological soft tissues exhibit viscoelastic relaxation during tensioning, a key protective mechanism.
- Current characterization methods often ignore or oversimplify this behavior, leading to inaccuracies.
- Existing correction methods are limited by specific viscoelastic formulations and strain histories.
Purpose of the Study:
- To develop a novel, formulation-independent correction method for stress relaxation experiments.
- To incorporate viscoelastic relaxation that occurs during the loading phase (ramp time).
- To accommodate arbitrary strain ramp histories in viscoelastic characterization.
Main Methods:
- Developed a finite ramp time correction method for stress relaxation experiments.
- Applied the correction method to quasi-linear viscoelastic (QLV) and fully nonlinear viscoelastic models.
- Validated the method by comparing its fitted parameters against independent cyclic experiments.
Main Results:
- The novel correction method significantly reduces errors compared to existing methodologies.
- Demonstrated the transferability of the correction method across different viscoelastic formulations (QLV and nonlinear).
- Identified significant errors in current methods for both QLV and nonlinear formulations.
Conclusions:
- The developed correction method accurately characterizes biological soft tissue viscoelasticity.
- Highlights the necessity of using fully nonlinear viscoelastic models that include loading-phase relaxation.
- Emphasizes the importance of this method for precise biomechanical analysis of soft tissues.
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