Transient dynamics response analysis of the limb under impact loading

Abstract

The limb vibrations are initiated at paw-strike in animals normal movement. The short ground contact duration suggests that there exists the transient dynamic response of the impact between the leg and ground, which is a high nonlinear problem and not well understood. The purpose of this study is to investigate the transient dynamic response of the lower limb of the felid during the moving. A kinematic model of the musculoskeletal system of a small felid is constructed from the anatomical measurement data. The elastic moduli are measured and calculated for different parts of the lower limb by a Nano-indentation technique. On the basis of the measured material parameters, the substructure technique is employed to numerically solve the contact-impact behavior of the lower limb. The high speed imaging system and a designed electronic detection system are employed in the experiment to testify the numerical results, which demonstrate that the initial impact has an important influence on the performance of the lower limb during the movement especially the high speed movement, and the paw-pad has good damping effects during the impact. The multiple impacts exist between limbs and the soil, which may provide the feedback energy for the felids high-speed running, though it may also increase the risk of the stress fracture of the limbs.