Ibáñez, R.; Abisset-Chavanne, E.; Chinesta, F.; Huerta, A. International journal of material forming Vol. 10, num. 5, p. 653-659 DOI: 10.1007/s12289-016-1309-4 Data de publicació: 2017-10 Article en revista
Thermoplastic composites are widely considered in structural parts. In this paper attention is paid to squeeze flow of continuous fiber laminates. In the case of unidirectional prepregs, the ply constitutive equation is modeled as a transversally isotropic fluid, that must satisfy both the fiber inextensibility as well as the fluid incompressibility. When laminate is squeezed the flow kinematics exhibits a complex dependency along the laminate thickness requiring a detailed velocity description through the thickness. In a former work the solution making use of an in-plane-out-of-plane separated representation within the PGD – Poper Generalized Decomposition – framework was successfully accomplished when both kinematic constraints (inextensibility and incompressibility) were introduced using a penalty formulation for circumventing the LBB constraints. However, such a formulation makes difficult the calculation on fiber tractions and compression forces, the last required in rheological characterizations. In this paper the former penalty formulation is substituted by a mixed formulation that makes use of two Lagrange multipliers, while addressing the LBB stability conditions within the separated representation framework, questions never until now addressed.
The final publication is available at Springer via http://dx.doi.org/10.1007/s12289-016-1309-4
The finite element method is the reference technique in the simulation of metal forming and provides excellent results with both Eulerian and Lagrangian implementations. The latter approach is more natural and direct but the large deformations involved in such processes require remeshing-rezoning algorithms that increase the computational times and reduce the quality of the results. Meshfree methods can better handle large deformations and have shown encouraging results. However, viscoplastic flows are nearly incompressible, which poses a challenge to meshfree methods. In this paper we propose a simple model of viscoplasticity, where both the pressure and velocity fields are discretized with maximum entropy approximants. The inf-sup condition is circumvented with a numerically consistent stabilized formulation that involves the gradient of the pressure. The performance of the method is studied in some benchmark problems including metal forming and orthogonal cutting.
Dialamishabankareh, N.; Chiumenti, M.; Cervera, M.; Agelet De Saracibar, C.; Ponthot, J. International journal of material forming Vol. 8, num. 2, p. 167-181 DOI: 10.1007/s12289-013-1157-4 Data de publicació: 2015-04 Article en revista
This work deals with the modeling of the material flow in Friction Stir Welding (FSW) processes using particle tracing method. For the computation of particle trajectories, three accurate and computationally efficient integration methods are implemented within a FE model for FSW process: the Backward Euler with Sub-stepping (BES), the 4-th order Runge-Kutta (RK4) and the Back and Forth Error Compensation and Correction (BFECC) methods. Firstly, their performance is compared by solving the Zalesak's disk benchmark. Later, the developed methodology is applied to some FSW problems providing a quantitative 2D and 3D view of the material transport in the process area. The material flow pattern is compared to the experimental evidence.
González, D.; Debeugny, L.; Cueto, E.; Chinesta, F.; Diez, P.; Huerta, A. International journal of material forming Vol. 3, num. 1, p. 883-886 DOI: 10.1007/s12289-010-0909-7 Data de publicació: 2010-04 Article en revista
We have developed a new method for the construction of Streamline Upwind Petrov Galerkin (SUPG) stabilization techniques for the resolution of convection-diffusion equations based on the use of separated representations
inside the Proper Generalized Decompositions (PGD) framework. The use of SUPG schemes produces a consistent stabilization adding a parameter to all the terms of the equation (not only the convective one). SUPG obtains an exact solution for problems in 1D, nevertheless, a generalization does not exist for elements of high order or for any system of convection-diffusion equations. We introduce in this paper a method that achieves stabilization in the context of Proper Generalzied Decomposition (PGD). This class of approximations use a representation of the solution by means of the sum of a finite number of terms of separable functions. Thus it is possible to use the technique of separation of variables in the context of problems of convection-diffusion that will lead to a sequence of problems in 1D where the parameter of
stabilization is well known.
Menargues, S.; Picas, J.A.; Martin, E.; Baile Puig, Maria Teresa; Campillo, M.; Forn, A. International journal of material forming Vol. 3, num. 1, p. 767-770 DOI: 10.1007/s12289-010-0883-0 Data de publicació: 2010-04 Article en revista
The aim of this study was to investigate the hard decorative anodizing components of A357 aluminium alloy, obtained in semisolid state by Sub Liquidus Casting® process, to improve its tribological properties and corrosion resistance.
Components were heat treated in order to modify the shape and distribution of the eutectic silicon phase. The influence
of shot peening pre-treatment on anodizing process was evaluated. Surface modifications were investigated as they might have beneficial effects on the wear and corrosion behaviour. Furthermore, the influence of surface condition on the anodization colouring behaviour of aluminium was studied.
The microstructure and the surface finish influence on the anodic oxide film growth were studied by optical and scanning electron microscopy. Experiments using a tribometer (ball on disc configuration) were performed in order to evaluate the tribological properties of the material. Salt spray corrosion tests were used to study the corrosion properties before and after the anodizing process.
Campillo, M.; Baile Puig, Maria Teresa; Menargues, S.; Forn, A. International journal of material forming Vol. 3, num. 1, p. 751-754 DOI: 10.1007/s12289-010-0879-9 Data de publicació: 2010-04 Article en revista
This work is a contribution to improve understanding about the behaviour of components produced by semi-solid processes. The present study shows the effect of different conformation parameters on automotive cranking cover production obtained by Semi-Solid Rheocasting Process (SSR®). The components were produced using EN AC-46500 alloy, by an industrial plant with a 700 Ton HPDC machine and an IDRA SSR Station.
The process parameters studied were slurry temperature, agitation time, speed injection and lubrication system. The characterization was carried out by microstructural analysis, X-rays and mechanical tests. The components show good mechanical properties, similar to those obtained by die cast. The process was simulated using the PROCAST program.
Chikarakara, E.; Aqida, S.; Brabazon, D.; Naher, S.; Picas, J.A.; Punset, M.; Forn, A. International journal of material forming Vol. 3, num. 1, p. 801-804 DOI: 10.1007/s12289-010-0891-0 Data de publicació: 2010 Article en revista
Picas, J.A.; Punset, M.; Menargues, S.; Campillo, M.; Baile Puig, Maria Teresa; Forn, A. International journal of material forming Vol. 2, num. suppl 1, p. 225-228 DOI: 10.1007/s12289-009-0466-0 Data de publicació: 2009-12 Article en revista
Menargues, S.; Campillo, M.; Baile Puig, Maria Teresa; Picas, J.A.; Forn, A. International journal of material forming Vol. 2 suppl 1, p. 769-772 DOI: 10.1007/s12289-009-0599-1 Data de publicació: 2009 Article en revista
López, R.; Ducoeur, B.; Chiumenti, M.; de Meester , B.; Agelet De Saracibar, C. International journal of material forming Vol. 1, num. 1, p. 1291-1294 DOI: 10.1007/s12289-008-0139-4 Data de publicació: 2008-04 Article en revista
Tejedor, R.; Rodríguez, R.; Benito, J.; Cabrera, J.; Prado, J. International journal of material forming Vol. 1, num. 1, p. 487-490 DOI: 10.1007/s12289-008-0109-x Data de publicació: 2008-04-01 Article en revista
Campillo, M.; Baile Puig, Maria Teresa; Martin, E.; Forn, A. International journal of material forming Vol. 1 sup 1, p. 989-992 DOI: 10.1007/s12289-008-0224-8 Data de publicació: 2008-01 Article en revista
This work demonstrates the possibility to apply T5 and T6 heat treatments to EN AC-46500
aluminium components conformed by Semi-Solid Rheocasting (SSR). The study of temperature and time
effect in annealing, tempering and artificial aging conditions has permitted to optimize the component
mechanical properties. The experimentation has been accomplished by means of hardness Brinell tests, tensile
tests, optic and electronic microscopy. The mechanical properties obtained in SSR components, reach
analogous values to the ones obtained by die cast components and submitted to the same heat treatments.