A dynamic Approach for Modeling the Amount of Soft Tissue Viscoelasticity with respect to Its Momentary Status

Abstract

One of the recent challenges in modeling is to determine and explain the behavior of a viscelastic material such as soft tissue. In order to correlate the soft tissue stress and strain, fractional order calculus is used as a promising approach. The tendency of soft tissue to behave as a pure viscous or pure elastic material is expressed by a parameter called order. Although stress and strain, as well as the order, are all functions of time, the purpose of this paper is to identify the order as a function of the state of the material. Therefore, it is necessary to somehow eliminate the time relationship between the order and the stress and strain pair and express the fractional order as a function of the momentary stress-strain. Here, this functionality considered as a dynamic model. To validate the proposed model, a state-space model is extracted using the results of previous studies estimated the order as an explicit function of time. The results of this novel dynamic model are then compared with the former methods. The obtained results show the efficiency of the proposed model.

Keywords

• soft tissue:viscoelastic material
• :dynamic identification
• :stress-strain relationship
• :non-integer order calculus
• : pem