No abstract

Maximal local loads in animal joints are necessary to design bio-inspired mechanical joints. Many studies presented methods to determine joint reaction forces in humans and animals. However, many of these methods are invasive, and no work has been published yet about the joint reaction forces in the horse forelimb during jumping. Non-invasive methods to measure the kinematics and ground reaction force of a horse forelimb were used in this work. A musculoskeletal model of horse forelimb was built with mechanical methods for the estimation of joint reaction forces. The entire forelimb was reconstructed by scanning real bones geometry with a 3D optical scanner and modeling all the muscles on a Computer Assisted Design (CAD) software. The model dynamics were simulated with OpenSim in order to estimate the joint loading. This study allows knowing an order of magnitude of the loads at the joints at jumping in order to determine latter the maximal joint contact loading values that will be a key at designing bio-inspired joints for mechanical assemblies.

Fibre kinking is one of the main failure modes of composite laminates under compression loading. In this paper, the role of kinking in the failure of quasi isotropic composites subjected to a bearing load is inves tigated. High resolution CT scans show that kinking is largely involved in the events leading to laminate collapse, notably by triggering other damage modes such as delamination. Kink bands develop extremely progressively, leading to the formation of a wide localization zone (or FPZ, failure process zone). Such behaviour calls for a non local modelling approach. Local damage models would lead to overly conserva tive sizing. A simple model, based on Hashin failure criteria and non local effective stresses is confronted to experiments, and its limits are highlighted. It will be shown that proper modelling of the bearing fail ure requires the characteristic behaviour of kink bands to be taken into account.