A viscoelastic sphere model for the representation of plantar soft tissue during simulations

Guler, HC
Berme, N
Simon, SR
Simulations of human body during locomotion require a realistic representation of the foot which is the major interacting part of the body with the environment. Most simulation models consider the foot to be a rigid link, and impose unrealistic kinematic conditions. This study utilizes a viscoelastic sphere model with realistic properties, which can be used to represent the plantar surface of the foot during locomotion. The mechanical properties of the sphere are identified using experimental data on heel pads (Valiant, 1984). To check the validity of the model the results of the experimental study are reproduced by simulating the impact tests. Sensitivity analyses of the model parameters are carried out. The model is found to be insensitive to variations in stiffness and damping properties. The change in the thickness of the soft tissue, however, affected the maximum force of deformation proportionally. ii symmetrical pressure distribution for the sphere during impact is calculated. It is concluded that the viscoelastic sphere model, presented here, can be incorporated into a foot model to represent the plantar surface of the foot.


A Vision Based Approach for Assessing Equine Locomotion and Whole-Body Vibration Induced on a Horse Rider
Tanil, Gozde; Soylu, Reşit (2013-07-05)
Biomechanical systems such as horse locomotion are investigated by using inertial sensor systems composed of accelerometers, gyroscopes and magnetometers, or by optical motion tracking systems. The major difficulty in the inertial sensor systems is the integration process. Furthermore, the signals possess noise that has to be filtered. On the other hand, the motion tracking systems are expensive and mostly adapted to indoor laboratory conditions. Hence, in some studies, horses are trained to walk on treadmi...
Using noisy work loops to identify the phase-dependent stiffness and damping of muscle in lampreys
Tytell, E. D.; Carr, J. A.; Danos, N.; Cowan, N. J.; Ankaralı, Mustafa Mert (2018-03-01)
Unlike most manmade machines, animals move through their world using flexible appendages, which bend due to internal muscle and body forces, but also due to forces from the environment. Fishes, in particular, must cope with fluid dynamic forces that not only resist their overall swimming movements but also may have unsteady flow patterns, vortices, and turbulence. We have been characterizing how the muscle tissue itself, due to its own intrinsic properties, is able to respond to perturbations. We have devel...
Sayginer, Ege; Akbey, Tulay; Yazıcıoğlu, Yiğit; Saranlı, Afşar (2009-05-17)
In this paper, we study the kinematics of a legged robot with half-circular leg morphology. In particular, our focus is on the RHex hexapod platform. A new kinematic model for RHex is developed considering the leg shape and its consequences, which was over simplified in the previous models seen in literature. The formulation is an accurate kinematic representation of the robot in the sagittal plane that is based on a four-link mechanism analogy. When only pure rolling motion of the legs are considered, it i...
A probabilistic design approach for rock slopes
DUZGUN, HSB; Karpuz, Celal; Yücemen, Mehmet Semih (1998-10-09)
The basic aim of this study is to develop a reliability-based methodology for the practical design of rock slopes. The advanced first-order second-moment (AFOSM) approach is adapted as;the reliability assessment model. In the reliability-based design methodology, the first step is the modeling and quantification of uncertainties associated with the design parameters. Since the safety of a rock slope is most sensitive to the shear strength of discontinuities, the uncertainty analysis is focused on the parame...
Modeling and control of autonomous underwater vehicle manipulator vehicle manipulator systems
Korkmaz, Ozan; İder, Kemal S.; Özgören, Mustafa Kemal; Department of Mechanical Engineering (2012)
In this thesis, dynamic modeling and nonlinear control of autonomous underwater vehicle manipulator systems are presented. Mainly, two types of systems consisting of a 6-DOF AUV equipped with a 6-DOF manipulator subsystem (UVMS) and with an 8-DOF redundant manipulator subsystem (UVRMS) are modeled considering hydrostatic forces and hydrodynamic effects such as added mass, lift, drag and side forces. The shadowing effects of the bodies on each other are introduced when computing the hydrodynamic forces. The ...
Citation Formats
H. Guler, N. Berme, and S. Simon, “A viscoelastic sphere model for the representation of plantar soft tissue during simulations,” JOURNAL OF BIOMECHANICS, pp. 847–853, 1998, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/66684.