Estimation of mechanical properties of soft tissue subjected to dynamic impact

Abstract

Human soft tissue is highly deformable leading to a difficulty in estimating itsmechanical properties. This paper focuses on the extraction of human tissue dampeningproperties under dynamic impact, which enabled an efficient implementation ofmechanical response of tissue, which is of growing interest and importance inbiomedical research and forensic science. Such properties are not only useful forrealistic surgical simulation, preoperative planning, and robot-assisted medicalprocedures, but also may be useful in deriving impact characteristics necessary tocause contusions for forensics purposes. The estimates of the damping propertiesof human soft tissue was done by using spring and damper system as a model; massdamper-spring (MDS). Spring stiffness is represented by the spring constant K anddashpot damping resistance is represented by the damper constant C. Data werecollected by striking human subjects with a weighted pendulum at different levelsof energy, velocity, and mass. The estimation process involved conditioning the data,such that the modeling process and estimation were feasible, resulting in estimates ofK and C. In conclusion, using impact data collected on living human tissue to estimatethe dampening properties is plausible. The results showed that both the stiffness andthe dampening resistance are highly correlated with the mass of the striking object, itsenergy and velocity. Hence, knowledge of these properties may be used in determiningthe impact parameters required by a striking object, which might be helpful in forensicinvestigation when contusions were induced.