Establishment of biaxial testing system for characterization of small animal ventricle viscoelasticity under physiological loadings
Date
2022
Authors
Roth, Kellan, author
Wang, Zhijie, advisor
Garrity, Deborah, committee member
McGilvray, Kirk, committee member
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Abstract
Ventricular dysfunction is a leading cause of heart failure. It is known that the mechanical behavior of both the left and right ventricles contribute to the function and changes during heart failure development. The ventricle tissue is viscoelastic meaning it is a stretch rate dependent material that exhibits both elastic and viscous behavior. The elasticity of the passive ventricular wall has been extensively investigated in cardiac research, but the viscous behavior is poorly understood. Moreover, as viscoelastic behavior is dependent on strain rate, characterizing the ventricle viscoelasticity under physiological loadings will invoke clinically relevant information. The objective of this thesis is to establish a biaxial testing system that can characterize rodent ventricle viscoelasticity under physiological loadings. The new tester was validated using polydimethylsiloxane (PDMS) sheets. The results from the biaxial tester's viscoelastic measurement of PDMS confirm that the tester is functioning properly for the measurement of viscoelastic soft tissue properties in small animal species under sinusoidal deformation at physiological stretch rates. Finally, rat right ventricular (RV) free walls in healthy and diseased specimens were characterized under physiological loadings. Significant alterations in viscoelastic properties and tissue anisotropy between the healthy and diseased tissues were observed. The rat RV study provides novel insight into the frequency-dependent and anisotropic viscoelasticity of the rat RV during heart failure development.
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Subject
cardiovascular
hysteresis
viscoelasticity
dissipated energy
biaxial
storage energy