This paper presents a method to determine the contact force and pressure on the surface of viscoelastic objects grasped by an endoscopic grasper, used in Minimally Invasive Surgery (MIS). Normally, an endoscopic grasper is corrugated (teeth-like) in order to grasp slippery tissues. It is highly important to avoid damage to the tissues during grasping and manipulation in endoscopic surgery. Therefore, it is essential to determine the exact contact force on the surface of the tissue. To this end, initially a comprehensive closed form analysis of grasping contact force and pressure on elastic and particularly viscoelastic materials which have similar behavior as that of biological tissues is studied. The behavior of a rigid grasper with wedge-like teeth, when pressed into a delayed elasticity material is being examined. Initially, a single wedge penetrating into a solid is studied and then is extended to the grasper. The elastic wedge indentation is the basis of this study and the effects of time are included in the equations by considering the corresponding integral operator from viscoelastic stress-stain relations. Under the action of a constant normal load, the penetration of the indenter and the contact area will change. In this research, the variation of the contact area with time and the grasping contact force is studied. The results of this study which provides a closed form expression for grasping contact force and contact area are compared with those from elastic analysis.
- Bioengineering Division
Grasping Contact Analysis of Viscoelastic Materials With Applications in Minimally Invasive Surgery
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Bonakdar, A, Dargahi, J, & Bhat, R. "Grasping Contact Analysis of Viscoelastic Materials With Applications in Minimally Invasive Surgery." Proceedings of the ASME 2006 International Mechanical Engineering Congress and Exposition. Advances in Bioengineering, Biomedical and Safety Systems. Chicago, Illinois, USA. November 5–10, 2006. pp. 75-80. ASME. https://doi.org/10.1115/IMECE2006-13081
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