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Updated: Jun 14, 2026
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Studying Large Amplitude Oscillatory Shear Response of Soft Materials
Published on: April 25, 2019
Strain-rate frequency superposition in large-amplitude oscillatory shear
Chirag Kalelkar1, Ashish Lele, Samruddhi Kamble
1Complex Fluids and Polymer Engineering Group, Polymer Science and Engineering Division, National Chemical Laboratory, Pune 411008, India. kalelkar@gmail.com
Summary
Soft solids exhibit strain-rate frequency superposition under large-amplitude oscillatory shear (LAOS). This property allows superposition of higher harmonic moduli onto master curves, simplifying analysis of viscoelastic behavior.
Area of Science:
- Rheology
- Soft Matter Physics
- Materials Science
Background:
- Soft solids display unique viscoelastic properties under shear.
- Previous work identified strain-rate frequency superposition in linear oscillatory shear.
- Extending this phenomenon to large-amplitude oscillatory shear (LAOS) is crucial for understanding nonlinear behavior.
Purpose of the Study:
- To investigate strain-rate frequency superposition in soft solids under LAOS.
- To analyze the behavior of higher harmonic moduli in nonlinear viscoelasticity.
- To determine the relationship between energy dissipation and viscoelastic moduli in soft solids.
Main Methods:
- Performed LAOS studies on a monodisperse hydrogel suspension, an aqueous gel, and a biopolymer suspension.
- Conducted constant strain-rate frequency sweep measurements.
- Analyzed higher harmonic moduli and energy dissipation rate per unit volume.
Main Results:
- Demonstrated strain-rate frequency superposition for higher harmonic moduli in soft solids under LAOS.
- Identified that higher harmonic moduli at low frequencies mirror behavior at large strain amplitudes.
- Showed that energy dissipated per unit volume depends solely on the first harmonic loss modulus, across linear and nonlinear regimes.
Conclusions:
- Strain-rate frequency superposition is a valid principle for soft solids even under LAOS conditions.
- The findings simplify the characterization of nonlinear viscoelasticity in soft materials.
- Energy dissipation in soft solids is directly linked to the linear loss modulus, irrespective of deformation amplitude.
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