Search results for "Contact analysis"
showing 6 items of 6 documents
Finite element analysis of two total knee joint prostheses
2012
Aim of this work is to compare two different total knee prostheses that differ mainly in the shape of the polyethylene (PE) component inserted between the femoral and tibial plates. The best solution between them has been originally reshaped in order to reduce stress peaks. The study procedure has been divided into the following steps. First step is the digitalisation of the shape of the prostheses by means of a 3D laser scanner. The morphology of two prototypes of the prostheses has been acquired by elaborating multiple Moire fringe patterns projected on their surfaces. Second step consisted on the manipulation of these data in a CAD module, that is the interpolation of raw data into NURBS…
On the Elastic Behavior of a Cross-Ply Composite Pin-Joint with Clearance Fits
1999
The effect of pin/hole clearance fits on the elastic membranal behavior of a cross-ply fiber glass-reinforced epoxy laminate plate loaded in tension through a pin is examined by a finite element nonlinear contact analysis. No a priori assumption is made on the distribution of the contact pressure on the surface of the hole. Friction effects are not included. The numerical results correlate well with Hertzian theory of contact. It is demonstrated that clearance increases the peak compressive stress in the plate up to a factor of 3000% with respect to the perfect-fit case. Clearance also shifts the location of the peak tensile stress towards the pin/hole contact arc and decreases its magnitu…
On the Effect of Interference Fits in Composite Pin-Joints
1999
The Finite Element Method is used to determine the effect of pin/hole interference fits on the elastic membranal behavior of an orthotropic plate loaded in tension through a pin. A complete contact analysis is performed to handle the nonlinear contact problem. The study encompasses two levels of interference fits, two degrees of anisotropy of the plate, and two load levels. Friction effects are not included. Experimental results from Digital Speckle Pattern Interferometry are also presented. It is shown that the stress changes in the plate vary linearly with load when no pin/plate separation occurs. It is also shown that interference fits can have beneficial effects on the static and fatig…
A Study on the Effects of Clearance and Interference Fits in a Pin-Loaded Cross-Ply FGRP Laminate
1998
The elastic behavior of a cross-ply fiber glass-reinforced epoxy laminate loaded in tension through a pin fitted with clearance and interference is examined. A nonlinear contact analysis using the Finite Element Method and an experimental study by Speckle Interferometry are performed, showing fairly good correlation. An interesting comparison is performed between FEM results and Hertzian contact theory. Major conclusions are: (I) clearance causes high compressive stress in the bearing area, and does not influence the peak tensile stress; (2) interference has beneficial effects on the joint, as (a) it lowers the peak circumferential stress, and (b) it decreases the change of stress due to t…
Active macro-zone approach for incremental elastoplastic-contact analysis
2013
SUMMARY The symmetric boundary element method, based on the Galerkin hypotheses, has found an application in the nonlinear analysis of plasticity and in contact-detachment problems, but both dealt with separately. In this paper, we want to treat these complex phenomena together as a linear complementarity problem. A mixed variable multidomain approach is utilized in which the substructures are distinguished into macroelements, where elastic behavior is assumed, and bem-elements, where it is possible that plastic strains may occur. Elasticity equations are written for all the substructures, and regularity conditions in weighted (weak) form on the boundary sides and in the nodes (strong) betw…
STRUCTURAL ANALYSIS OF A POSTERIOR STABILITY TOTAL KNEE JOINT REPLACEMENT
2011
Aim of this work is to compare two different total knee prostheses that differ in the shape of the Polyethylene (PE) insert, trying to optimize the shape of the best one, in order to reduce the stress peaks. The study procedure has been divided into the following steps. First step has been the three-dimensional shape acquisition of the two prostheses by means of a COMET5 3D scanner. The morphology of two prototypes of the prostheses has been acquired by elaborating multiple Moirè fringe pattern projected on their surfaces. Second step consisted of the manipulation of these data in a CAD module, that is the interpolation of raw data into parametric surfaces, reducing singularities due to the…