7
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
L. Lamberson et al. (eds.), Dynamic Behavior of Materials, Volume 1, Conference Proceedings of the Society
for Experimental Mechanics Series, https://doi.org/10.1007/978-3-030-59947-8_2
Chapter 2
Expanding Inertial Microcavitation Rheometry to Cover Large
Material Stretches in Soft Materials
Selda Buyukozturk and Christian Franck
Abstract The existence of cavitation in soft materials introduces challenging problems as it exhibits unique deformation
and failure mechanisms. Soft materials behave differently under high strain-rates than under quasi-static loading conditions.
Particularly, the effects of strain-rates in the ballistic and blast ranges are unknown. Laser-induced cavitation (LIC) is a thermally driven inertial process for generating large deformations at high to ultra-high strain- rates in optically transparent
materials by way of cavitation. This study focuses on LIC as a reliable and robust experimental method for characterizing
the constitutive response of materials across an order of magnitude in material stretches. Through the integration of an appropriate theoretical framework, material stresses and strains during cavitation can be estimated for homogeneous, isotropic
materials with Inertial Microcavitation Rheometry (IMR), a tool developed to characterize the nonlinear viscoelastic properties of soft materials at high strain-rates. The long-time bubble radius at mechanical equilibrium and maximum bubble
radius, defined as the material stretch in the hydrogel, determine the initial gas pressure in the bubble to initialize the simulation. However, the current theoretical framework was developed with limited experimental modulation of bubble amplitude,
limiting the regime of accessible material deformations. Furthermore, the model neglects to address inelastic material behavior at large material stretches. In this work, an extensive library of material stretches due to bubble oscillation are experimentally achieved to identify critical material stretches during the transition from viscoelastic to inelastic behavior by
systematically controlling bubble amplitude and material deformations over a large stretch range. This library of material
stretches defined by the bubble dynamics are used in the simulation to test the robustness of IMR, and identify new avenues
for future theoretical and numerical developments. In sum, this critical experimental data will lay the foundation for incorporating damage and failure mechanisms of inelastic behavior of soft materials undergoing high strain-rate deformations.
Keywords Laser-induced cavitation (LIC) · Inertial microcavitation rheometry (IMR) · Ultra-high strain-rate · Bubble
amplitude · Material stretch
2.1 Introduction
The recent recognition and use of cavitation in biological and other soft material systems has motivated the development of
understanding bubble dynamics in and near soft materials. Specific applications include the study of biological tissues, polymeric coatings, biofouling, composites, and other synthetic materials. Laser-induced cavitation (LIC) is a thermally driven
inertial process with the ability to characterize material behavior at high strain-rate (10
3
–10
8
s
−1
) deformations. Through the
integration of an appropriate theoretical framework, material stresses and strains during cavitation can be estimated for
homogeneous, isotropic materials through Inertial Microcavitation Rheometry (IMR), a tool we recently developed to characterize the nonlinear viscoelastic properties of soft materials at high strain-rates [1].
S. Buyukozturk (*)
School of Engineering, Brown University, Providence, RI, USA
Department of Mechanical Engineering, University of Wisconsin–Madison, Madison, WI, USA
e-mail: selda_buyukozturk@brown.edu
C. Franck
Department of Mechanical Engineering, University of Wisconsin–Madison, Madison, WI, USA
e-mail: cfranck@wisc.edu
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
L. Lamberson et al. (eds.), Dynamic Behavior of Materials, Volume 1, Conference Proceedings of the Society
for Experimental Mechanics Series, https://doi.org/10.1007/978-3-030-59947-8_2
Chapter 2
Expanding Inertial Microcavitation Rheometry to Cover Large
Material Stretches in Soft Materials
Selda Buyukozturk and Christian Franck
Abstract The existence of cavitation in soft materials introduces challenging problems as it exhibits unique deformation
and failure mechanisms. Soft materials behave differently under high strain-rates than under quasi-static loading conditions.
Particularly, the effects of strain-rates in the ballistic and blast ranges are unknown. Laser-induced cavitation (LIC) is a thermally driven inertial process for generating large deformations at high to ultra-high strain- rates in optically transparent
materials by way of cavitation. This study focuses on LIC as a reliable and robust experimental method for characterizing
the constitutive response of materials across an order of magnitude in material stretches. Through the integration of an appropriate theoretical framework, material stresses and strains during cavitation can be estimated for homogeneous, isotropic
materials with Inertial Microcavitation Rheometry (IMR), a tool developed to characterize the nonlinear viscoelastic properties of soft materials at high strain-rates. The long-time bubble radius at mechanical equilibrium and maximum bubble
radius, defined as the material stretch in the hydrogel, determine the initial gas pressure in the bubble to initialize the simulation. However, the current theoretical framework was developed with limited experimental modulation of bubble amplitude,
limiting the regime of accessible material deformations. Furthermore, the model neglects to address inelastic material behavior at large material stretches. In this work, an extensive library of material stretches due to bubble oscillation are experimentally achieved to identify critical material stretches during the transition from viscoelastic to inelastic behavior by
systematically controlling bubble amplitude and material deformations over a large stretch range. This library of material
stretches defined by the bubble dynamics are used in the simulation to test the robustness of IMR, and identify new avenues
for future theoretical and numerical developments. In sum, this critical experimental data will lay the foundation for incorporating damage and failure mechanisms of inelastic behavior of soft materials undergoing high strain-rate deformations.
Keywords Laser-induced cavitation (LIC) · Inertial microcavitation rheometry (IMR) · Ultra-high strain-rate · Bubble
amplitude · Material stretch
2.1 Introduction
The recent recognition and use of cavitation in biological and other soft material systems has motivated the development of
understanding bubble dynamics in and near soft materials. Specific applications include the study of biological tissues, polymeric coatings, biofouling, composites, and other synthetic materials. Laser-induced cavitation (LIC) is a thermally driven
inertial process with the ability to characterize material behavior at high strain-rate (10
3
–10
8
s
−1
) deformations. Through the
integration of an appropriate theoretical framework, material stresses and strains during cavitation can be estimated for
homogeneous, isotropic materials through Inertial Microcavitation Rheometry (IMR), a tool we recently developed to characterize the nonlinear viscoelastic properties of soft materials at high strain-rates [1].
S. Buyukozturk (*)
School of Engineering, Brown University, Providence, RI, USA
Department of Mechanical Engineering, University of Wisconsin–Madison, Madison, WI, USA
e-mail: selda_buyukozturk@brown.edu
C. Franck
Department of Mechanical Engineering, University of Wisconsin–Madison, Madison, WI, USA
e-mail: cfranck@wisc.edu