Christian Hochard

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Osteoporosis is a bone disease related to age, it weakens bone structure by deterioration of the trabecular architecture and decreases the cortical envelop width and increases its porosity. Hip fractures are the more recurrent consequences of osteoporosis, and are the cause of morbidity and increase the rate of mortality. The fracture risk due to(More)
This study deals with the optimisation of hybrid composite drive shafts operating at subcritical or supercritical speeds, using a genetic algorithm. A formulation for the flexural vibrations of a composite drive shaft mounted on viscoelastic supports including shear effects is developed. In particular, an analytic stability criterion is developed to ensure(More)
The damping in a carbon fiber reinforced plastic (CFRP) laminate is greater than that which occurs in most metallic materials. In the supercritical regime, the damping can trigger unstable whirl oscillations, which can have catastrophic effects. The vibrations occurring in a supercritical composite drive shaft are investigated here in order to predict(More)
INTRODUCTION Schizophrenia causes psychological difficulties (with positive and/or negative symptoms) as well as cognitive disabilities (attention, memory, executive functions and social cognition). Moreover, 40 to 60% of patients suffer from an excess of weight or obesity (due to bad eating habits, eating disorders or medication). All these difficulties(More)
Cognitive impairments associated with schizophrenia are very frequent. They concern both neurocognition and social cognition, including facial emotion recognition. These impairments have a negative impact on the daily functioning, in particular the social and vocational rehabilitation of people with schizophrenia. Previous studies in this area clearly(More)
Woven ply laminates show a good resistance to delamination and do not present any premature traverse failure on all the thickness of the ply because of the weaving [1]. In addition it was observed experimentally that, in case of static loadings conditions, failure of a ply generally has catastrophic effects on the structure. In case of woven plies, failure(More)
Trefftz approximations are known to require very few degrees of freedom to give an order of magnitude of the solution. In this paper, we show that it is possible to take advantage of this situation in two ways: (i) we show that it is also possible to get accurate solutions (especially for the pressure) at a reasonable cost and (ii) we show that the low(More)
This paper presents a method for a quick evaluation of stresses and displacements for elastostatic problems. A set of polynomial Trefftz functions and a variational formulation are introduced for solving elastostatic problems for simple star-shaped domains. It is shown, through examples, that this approximation allows the computation of the interior large(More)
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