In-vivo testing of biological bulk soft tissues by a non-axisymmetric tip indenter using displacement and force control

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2015

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Ashrafi, Parinaz

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Soft tissues of human body have complex structures and different mechanical behaviors than those of traditional engineering materials. There is a great urge to understand tissue behavior of human body. Experimental data is needed for improvement of soft tissue modeling and advancement in implants and prosthesis, as well as diagnosis of diseases. Mechanical behavior and responses change when tissue loses its liveliness and viability. One of the techniques for soft tissue testing is indentation, which is applied on live tissue in its physiological environment. Indentation affords several advantages over other types of tests such as uniaxial tension, biaxial tension, and simple shear and suction, thus it is of interest to develop new indentation techniques from which precise data can be extracted. In this study experimental data was acquired using a soft tissue indenter designed and manufactured in METU. For real time data collection computer codes with a graphical user interface was developed in LabVIEW programming software. The in-vivo force rate controlled cyclic loading test method which is novel is compared with the traditional displacement controlled cyclic loading tests. Displacement and force rate cyclic loading, and relaxation experiments were conducted on human arm. In addition to viscoelastic behavior of soft tissue, the anisotropic behavior and preconditioning behavior of human arm soft tissues were examined. Anisotropic behavior of tissue cannot be determined by axi-symmetric tips, therefore ellipsoid tips were designed and used for examining in-plane anisotropy of bulk soft tissues.Finally, precise experimental data, to be used in the computer simulations, were obtained.

Subject Keywords

Tissue engineering., Tissues, Anisotropy., Viscoelasticity., Biomechanics.

URI

http://etd.lib.metu.edu.tr/upload/12618564/index.pdf
https://hdl.handle.net/11511/24505

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Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

P. Ashrafi, “In-vivo testing of biological bulk soft tissues by a non-axisymmetric tip indenter using displacement and force control,” M.S. - Master of Science, Middle East Technical University, 2015.