Papers by Daniel Delfosse
Surgical thread tensioner
Surgical thread tensioning device (10) for tensioning a thread to be fixed to an implant having a... more Surgical thread tensioning device (10) for tensioning a thread to be fixed to an implant having a tubular shank (11) of an axial passage opening (18) and having a distal end (22) and a proximal end (21). The thread-tensioning device (10) further has a contact element (13) connected to the proximal end (21) of the shaft (11) and having an opening (9), (the end of the contact element facing away from the said shaft (11) 13) partially (in the axial direction by the contact member 13), and a clamping element (14) with a thread holder (15) for fixing a thread. The thread holder (15) is laterally adjacent to the shaft (11) mounted, so that the thread outside of the axial passage opening (18) and the axial through hole (18) for introducing an auxiliary tool remains free.
Low metallic wear of dynamic intraligamentary stabilization
Tribology International, 2017
Abstract Dynamic Intraligamentary Stabilization (DIS) represents a treatment option for acute ant... more Abstract Dynamic Intraligamentary Stabilization (DIS) represents a treatment option for acute anterior cruciate ligament ruptures. The device used for DIS consists of a polyethylene braid and a metallic spring system, allowing the remnants of the ligament to recombine in a stabilized position over the self-healing period. This work addresses the metallic wear generated thereby. A cadaveric study was carried out with n=8 knees over 50'000 cycles, along with a control group to validate the cleaning and assembly process. Gravimetric analysis yielded a total wear of (0.28±0.35)mg for the entire implant. 50% of the wear originated from the bush and 46% from the clamping element. In a worst case scenario, a total wear of 1.7 mg would result during the functional lifetime.
Positioning instrument for inserting an extension shell
System for controlled loading of reconstructed or restored ligament i.e. front cruciate ligament, into knee joint of e.g. human body, has elastomer body guiding interaction of body with anchoring and connecting elements at elastic effect
NOVELTY - The system (100) has an anchoring element (10) implanted in a first bone (41) and inclu... more NOVELTY - The system (100) has an anchoring element (10) implanted in a first bone (41) and including a connecting element (20) and a retaining element (30), which fixes the connecting element to a second bone (51). An elastomer body is arranged in the anchoring element and/or connecting element, and guides interaction of the elastomer body with the anchoring element and the connecting element at defined elastic effect of the system. The elastomer body has small elastic modulus than that of the connecting element, and a sleeve is movably mounted in an outer body. USE - System for controlled loading of a reconstructed or restored ligament i.e. front cruciate ligament, into a knee joint of a human or animal body. ADVANTAGE - The system enables controlled loading of the reconstructed or restored ligament of the knee joint of the human or animal body in a simple and effective manner with enhanced convenience of the patient and without the intervention salvages risk and the risk of irrit...
Implantable system having elastic components
Fundamentals of Functionally Graded Materials
Materials Today, 1998
Ligament tensioning device with cutting jig, and osteotomy method
Resektionsschnittlehre und Verfahren zur Positionierung einer Resektionsschnittlehre
Gelenkprothese mit Elastomer- oder Federelement
Self-Aligning Knee Prosthesis
Ligament-Tentioning Device, Section Template and Osteotomy Method
Joint prosthesis with elastomeric or spring element
Ligament-tensioning device e.g. for preparing implantation of articulated implant, has base body having claws provided with bearing surfaces applied to bone part
Gelenkprothese mit Zwischenelement mit unterschiedlich gestalteten Gleitflächen
Non-Penetrating Impact Behavior of CFRP at Low and Intermediate Velocities
Composite Materials: Fatigue and Fracture: Fifth Volume
... is the evolution of damage under impact loading and the consequent reduction in strength and ... more ... is the evolution of damage under impact loading and the consequent reduction in strength and stiffness. ... It is not clear at what stage there is a transition in the impact behavior from a ... Laboratory experiments at the correct energy level but at low velocities may accurately simulate ...
High-speed impact response of particulate metal matrix composite materials—An experimental and theoretical investigation
International Journal of Impact Engineering, 1993
ABSTRACT A combined experimental and numerical investigation of the high strain rate behaviour of... more ABSTRACT A combined experimental and numerical investigation of the high strain rate behaviour of ceramic particle reinforced metal matrix composites (MMCs) has been undertaken. Experimental results consisting of dynamic penetration tests (DPT), Taylor cylinder impact (TCI) tests, split Hopkinson pressure bar (SHPB) tests, and conventional mechanical tests are presented. A flow stress model based on isotropic plasticity theory has been developed and implemented into the DYNA2D finite element hydrodynamic code. The model is especially suited for describing the behaviour of MMCs as it provides for a smooth transition from brittle to ductile type behaviour with increasing values of hydrostatic pressure. This constitutive model is phenomenological in nature, and reduces to the more familiar Johnson—Cook (J—C) and Zerilli—Armstrong (Z—A) flow stress models as special limiting cases. The parameters of these models were calibrated based on the SHPB test results. Hydrocode simulations of the TCI tests were conducted in order to validate the models at high rates of loading. The satisfactory agreement between predicted and measured post-TCI profiles provided confidence in applying the code to numerical simulation of the DPTs. Computational results are presented and correlated with the corresponding experimental data for both reinforced and unreinforced systems. Finally, the advantages and shortcomings of hydrocodes for predictive purposes are discussed.
An engineering model for deformation of CFRP plates during penetration
Composite Structures, 1995
The response of brittle CFRP laminated plates to penetration by cylindrical indenters has been st... more The response of brittle CFRP laminated plates to penetration by cylindrical indenters has been studied using a combined experimental and analytical investigation. The two major damage modes caused by delamination and plugging are found to divide the plate response into three distinct stages. An analytical model, which accounts for the geometric parameters of the response, is developed to describe the
Matériaux à gradient : exploitation du concept et techniques de production par métallurgie des poudres
Revue de Métallurgie, 1996
Les materiaux a gradient de composition, appeles aussi FGMs par reference a leur nomination angla... more Les materiaux a gradient de composition, appeles aussi FGMs par reference a leur nomination anglaise (Functional Gradient Materials), representent un nouveau concept de fabrication de pieces avec des proprietes et/ou fonctions qui ne peuvent pas etre remplies par les materiaux classiques homogenes. Leur simple structure consiste en une evolution graduelle d'une surface a l'autre par un changement continu de la composition. Leur profil de transition doit etre predefini et introduit afin d'obtenir la fonction desiree. Dans ce sens, les materiaux a gradients peuvent sans aucun doute etre classes dans une categorie distincte de celle des composites classiques.
Evaluation and Modelling of the Residual Stresses Generated on Functionally Graded Materials -Two examples
Functionally Graded Materials 1996, 1997
1. ABSTRACT A parametric study was carried out to determine the influence of the compositional gr... more 1. ABSTRACT A parametric study was carried out to determine the influence of the compositional gradient on the residual stress distribution. The calculations were based on a cylindrical geometry for WC/Co samples and a rectangular geometry for CuNi samples with stepwise compositional variation at the interlayers. The effects of the gradation size and composition profile of the graded materials were investigated by a visco-elasto-plastic finite element analysis using the ABAQUS code. It was found that the degree of residual stress is mostly determined by the compositional distribution and its thickness, but not by the thermal history. The calculated stress values were compared with those measured experimentally either by X- ray diffraction on graded WC/Co specimens or by deflection measurements during electrochemical removal of subsequent layers for graded CuNi samples. The comparison with experimental methods showed good agreement, thus validating the results obtained by the parametric finite element study.
Experimental determination of residual stresses in materials with a one-dimensional gradient of composition
Acta Metallurgica et Materialia, 1992
Abstract In copper-nickel alloys, the coefficient of thermal dilatation is a strong function of t... more Abstract In copper-nickel alloys, the coefficient of thermal dilatation is a strong function of the composition. By a careful choice of the composition gradient and the heat treatment, tailored residual stress profiles can be generated. These profiles are determined by deflection measurements during electro-chemical removal of subsequent layers. The necessary functional relations between the original stress profile and the bending of the non-homogeneous sample are derived. In experiments with the chosen alloy system, residual stress values up to 85 MPa were attained.
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Papers by Daniel Delfosse