Philippe Lorong

Bio: Philippe Lorong is an academic researcher from Arts et Métiers ParisTech. The author has contributed to research in topics: Machining & Finite element method. The author has an hindex of 12, co-authored 63 publications receiving 530 citations. Previous affiliations of Philippe Lorong include University of Paris & University of Zaragoza.

A new extension of the natural element method for non-convex and discontinuous problems: the constrained natural element method (C-NEM)

Abstract: In this paper a new extension of the mesh-free natural element method (NEM) is presented. In this approach, coined as constrained natural element method (C-NEM), a visibility criterion is introduced to select natural neighbours in the computation of the shape functions. The computation of these shape functions is based on a modified, constrained Voronoi diagram. With this technique, some difficulties inherent to this method in non-convex domains are avoided and the analysis of problems involving cracks or discontinuities are now easily performed. As the NEM satisfies the Kronecker delta property, the imposition of essential boundary conditions is trivial, unlike other mesh-free methods. The C-NEM technique provides a description of integration cells that allows the use of the stabilized conforming nodal integration (SCNI) scheme instead of Gauss integration to enhance computational efficiency and accuracy. Two numerical examples in elastostatics are reported to evaluate the potential of the proposed technique in highly non-convex geometries, like a crack, through which the solution becomes discontinuous.

Meshless Methods and Partition of Unity Finite Elements

Abstract: This paper encompasses the main conclusions obtained in the mini-symposium New and Advanced Numerical Strategies in Forming Processes Simulation, held during the 6th International ESAFORM Conference on Material Forming (Salerno 2003), particularly those aspects dealing with meshless and partition of unity methods applied to the simulation of forming processes

Physically Based Deformable Models in Computer Graphics

Abstract: Physically based deformable models have been widely embraced by the Computer Graphics community. Many problems outlined in a previous survey by Gibson and Mirtich [ GM97] have been addressed, thereby making these models interesting and useful for both offline and real-time applications, such as motion pictures and video games. In this paper, we present the most significant contributions of the past decade, which produce such impressive and perceivably realistic animations and simulations: finite element/difference/volume methods, mass-spring systems, meshfree methods, coupled particle systems and reduced deformable models based on modal analysis. For completeness, we also make a connection to the simulation of other continua, such as fluids, gases and melting objects. Since time integration is inherent to all simulated phenomena, the general notion of time discretization is treated separately, while specifics are left to the respective models. Finally, we discuss areas of application, such as elastoplastic deformation and fracture, cloth and hair animation, virtual surgery simulation, interactive entertainment and fluid/smoke animation, and also suggest areas for future research.

Physically Based Deformable Models in Computer Graphics.

Abstract: Physically based deformable models have been widely embraced by the Computer Graphics community. Many problems outlined in a previous survey by Gibson and Mirtich [ GM97] have been addressed, thereby making these models interesting and useful for both offline and real-time applications, such as motion pictures and video games. In this paper, we present the most significant contributions of the past decade, which produce such impressive and perceivably realistic animations and simulations: finite element/difference/volume methods, mass-spring systems, meshfree methods, coupled particle systems and reduced deformable models based on modal analysis. For completeness, we also make a connection to the simulation of other continua, such as fluids, gases and melting objects. Since time integration is inherent to all simulated phenomena, the general notion of time discretization is treated separately, while specifics are left to the respective models. Finally, we discuss areas of application, such as elastoplastic deformation and fracture, cloth and hair animation, virtual surgery simulation, interactive entertainment and fluid/smoke animation, and also suggest areas for future research.

Point based animation of elastic, plastic and melting objects

Abstract: We present a method for modeling and animating a wide spectrum of volumetric objects, with material properties anywhere in the range from stiff elastic to highly plastic. Both the volume and the surface representation are point based, which allows arbitrarily large deviations form the original shape. In contrast to previous point based elasticity in computer graphics, our physical model is derived from continuum mechanics, which allows the specification of common material properties such as Young's Modulus and Poisson's Ratio.In each step, we compute the spatial derivatives of the discrete displacement field using a Moving Least Squares (MLS) procedure. From these derivatives we obtain strains, stresses and elastic forces at each simulated point. We demonstrate how to solve the equations of motion based on these forces, with both explicit and implicit integration schemes. In addition, we propose techniques for modeling and animating a point-sampled surface that dynamically adapts to deformations of the underlying volumetric model.