An analytical model taking feed rate effect into consideration for scallop height calculation in milling with torus-end cutter

International audienceFeed rate effect on scallop height in complex surface milling by torus-end mill is rarely studied. In a previous paper, an analytical predictive model of scallop height based on transverse step over distance has been established. However, this model doesn’t take feed rate effect into consideration. In the present work an analytical expression of scallop height, including feed rate effect, is detailed in order to quantify feed rate effect and thus to estimate more precisely the surface quality. Then, an experimental validation is conducted, comparing the presented model predictions with experimental results. Actually, the share of the scallop height due to feed effect is highly dependent on the machining configuration. However, most of time, the feed effect on total scallop height values is far from being negligible

Hot tearing test for TIG welding of aluminum alloys: application of a stress parallel to the fusion line

Welding processes are extensively used to assemble components in many manufacturing industries, such as aeronautics, construction, energy and automotive. To increase their productivity, constructors try to reduce manufacturing time. This involves for welding operations an increase of welding speed. However, various defects such as hot tearing might limit this increase. Hot tearing appears at the solidification end of an alloy, and is commonly observed in welding. During welding, components are subjected to high thermal gradients around the melting zone due to localized heat input. The solidification zone, where microstructure forms, is located at the rear of the melting zone and is bordered by two isothermal surfaces corresponding to liquidus and solidus temperatures. In welding, due to high thermal gradients, solidification by epitaxial growth of columnar dendrites is generally observed from the border of the melting zone. However, equiaxed dendritic grains can also form in the center area of the melting zone

Un modèle d\u27endommagement ductile orthotrope pour des transformations finies.

L\u27endommagement ductile dans les matériaux est habituellement traité à partir d\u27un modèle de Gurson ou de Gologanu-Leblond pour des cavités sphériques ou axisymmétriques dans l\u27axe du chargement. On présente une méthode prenant en compte l\u27existence d\u27une inclusion et l\u27orientation de l\u27ellipsoide à partir d\u27une loi de normalité macroscopique associée. L\u27intégration numérique des modèles est souvent programmé pour une résolution explicite. On propose un schéma implicite à deux niveaux prenant en compte l\u27évolution de l\u27orientation des défauts. Ces divers schémas sont ensuite appliquées à des procédés de mise en forme

A Generic Framework for Natural and Finite Element Method

International audienceNumerical techniques are more and more sophisticated and each kind of method have its own field of applications. Concerning multi-physics analysis, it is more and more relevant to be able to combine different methods to solve complex problems

Modelling of hot cracking in welding with a cellular automaton combined with an intergranular fluid flow model

International audienceHot cracking phenomena in welds are still a major issue to choose suitable welding conditions. Solidification cracking in welds depends on microstructure morphology, thermal and mechanical loadings. It is still difficult to discriminate the influence of the different phenomena because they are all connected. To investigate solidification cracking, numerical modelling that integrates most of these phenomena is developed in this paper. Thermal and mechanical fields are computed with a finite element model at the process scale. The thermal field is combined with a cellular automata (CA) to predict microstruc-ture at a meso scale. Based, on this prediction, the intergranular network is extracted. Finally, the pressure in the intergranular fluid network is computed during solidification. The fluid flow model along grain boundaries predicts an eventual nucleation of pore/void in the remaining liquid by investigating the maximum pressure drop in the solidifying microstructure. The numerical model is able to describe some hot cracking phenomena observed during experimental tests

A progressive first ply failure model for woven ply CFRP laminates under static and fatigue loads

A non-linear cumulative damage model for woven ply laminates under static and fatigue loads is developed in this paper. The validity scope of this model depends on the ‘diffuse damage’ phase up to the first intra-laminar macro-crack only (first ply failure model). The model, which is based on a continuum damage approach (CDM) and a non-local fibre rupture criteria, was implemented in a FEM code. Finally, full field strain measurements are used to compare experiments and computations for a plate with an open hole submitted to a fatigue tensile load

A ply scale non local fibre criterion for CFRP women ply laminates structures

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