Search results for "physics.class-ph"
showing 10 items of 334 documents
Influence of the Microgeometry on the Cylindrical Fit Characteristics
1995
International audience
Systematic Error Correction of a 3D laser scanning Measurement Device
2007
International audience
Planification de la trajectoire automatique pour la mesure d'objet 3D sans contact
2009
International audience
Modelling of a Circular Shrinkage Fit in Taking into account of the Form Defect
1996
International audience
Effective orifice area assessment in BI-leaflet mechanical valves by MRI,
2016
International audience; Effective orifice area (EOA) and mean pressure gradientare routine echocardiographic measurements of valvularprosthesis function in both the mitral and aortic position.EOA computation is based on the continuity equationand is used to describe the “effective” orifice formed bythe flow traversing a geometrical orifice. In the case ofbi-leaflet biomechanical valvular prosthesis (BMHV),the orifice of the valve is divided into 3 zones. BMHVperformance assessment by MRI have been described inthe in-vitro setting in [1] using the maximum pressuregradient. Additionally, a method using jet layer has beenused to detect EOA dynamically [2]. 4D-PC flowsequences enable measuremen…
Construction d'un élément fini d'interface homogénéisé pour prendre en compte l'effet de la rugosité dans la modélisation des assemblages frettés
2013
International audience; Le frettage est un procédé qui permet d'assembler deux pièces par serrage. Les méthodes de calcul traditionnelles considèrent ces pièces parfaites et ne prennent pas en compte leurs défauts géométriques (forme et états de surface). Ceci oblige généralement à utiliser des procédés onéreux pour obtenir ces surfaces. L'objectif des travaux présentés ici est de pouvoir intégrer le comportement de la micro géométrie des aspérités dans la modélisation des assemblages frettés. L'approche envisagée consiste à élaborer un élément d'interface présentant le comportement des aspérités. Le comportement de cet élément peut alors être défini par une relation entre son épaisseur (li…
Validation of in-vitro strain measurement by Magnetic Resonance Imaging of realistic abdominal aortic aneurism phantom
2016
International audience; Preoperative diagnostic protocols of abdominal aortic aneurysm (AAA) are today mainlybased on the measurement of the aortic maximum diameter. This measurement is insufficient becausethe diameter is not a discriminant variable for predicting the rupture of the aorta. Recent works showthe importance of determining the wall stress both due to the aortic shape, the pressure and the bloodflow. The problem is very complex and requires the implementation of sophisticated models takinginto account the heterogeneity of tissues and the complexity of flow. Then it is essential to validatethe capacity of existing medical imaging systems to provide reliable measurements that will…
Path Planning in Inspection Process of 3-D Parts Used the Visibility Technique
2006
International audience; In this paper presents a new method for digitalization of parts with non-contact sensor remains nevertheless complex. It is not completely solved today, in particular from a metrological point of view. In this article, we consider the determination of the trajectory planning within the framework of the control of dimensional and geometrical specifications. The sensor used in this application is a laser planner scanner with CCD camera oriented and moved by a CMM. Thus, we seek to determine which are the best possible orientations of the sensor with respect to the geometrical specifications of the measured part, giving the admissible measurement uncertainties. The deve…
3D surfaces automated acquisition using non contact sensor with repect of metrological conditions
2013
International audience
Digital Correlation Method Based on Microgeometrical Texture Patterns for Strain Fields Measurements
2005
International audience; Digital correlation method is widely used in experimental mechanics to obtain the deformation field. Currently this method is applied with digital images of the initial and deformed surface sprayed with black or white painting. Speckle patterns are then captured and the correlation can be made with high 0.01 pixel accuracy in 2D-cases. In three-dimensions, the stereo-correlation can be used with a lower accuracy. The work presented in this paper, is a first approach based on the use of a 3D laser scanner in the objective of three-dimensional strain field measurement. The digital speckle patterns are not given by gray level but from the micro-geometrical surface textu…