Insights into the mechanical interaction between an active cranial implant and the skull subjected to moderate impact loadings.

In the context of cochlear implants, which are now widely used, and innovative active devices, the cranial implantation of electronic devices raises new questions about the mechanical interactions between the implant and the skull. The aim of this study was to build a methodology using experimental data and numerical simulations to evaluate the mechanical interactions between the skull and the WIMAGINE® active cranial implant intended for use for tetraplegic patients. A finite element model of the implant housing and a simplified model of the three-layered skull were developed.

Johnson-Cook Parameter Identification for Commercially Pure Titanium at Room Temperature under Quasi-Static Strain Rates.

Background: To simulate mechanical shocks on an intracranial implant called WIMAGINE, Clinatec chose a Johnson-Cook model to account for the viscoplastic behavior of grade 2 titanium in a dynamic study using Radioss.

Methods: Thirty tensile specimens were subjected to tensile tests at room temperature, and the influence of the strain rate (8 × 10 and 8 × 10 s) and sandblasting was analyzed. Relaxations were included in the tests to analyze viscosity phenomena.

Changes in wheelchair biomechanics within the first 120 minutes of practice: spatiotemporal parameters, handrim forces, motor force, rolling resistance and fore-aft stability.

During manual wheelchair (MWC) skill acquisition, users adapt their propulsion technique through changes in biomechanical parameters. This evolution is assumed to be driven towards a more efficient behavior. However, when no specific training protocol is provided to users, little is known about how they spontaneously adapt during overground MWC locomotion.

Shoulder kinetics during start-up and propulsion with a manual wheelchair within the initial phase of uninstructed training.

Purpose: Wheelchair locomotion is constraining for the upper limbs and involves a set of motor tasks that need to be learnt by a novice user. To understand this integration process, we investigated the evolution of shoulder kinetics during start-up and propulsion within the initial phase of low-intensity uninstructed training.

Materials And Methods: Seventeen novice able-bodied subjects performed a 120-min uninstructed practice distributed over 4 weeks.