Merging enriched Finite Element triangle meshes for fast prototyping of alternate solutions in the context of industrial maintenance

A new approach to the merging of Finite Element (FE) triangle meshes is proposed. Not only it takes into account the geometric aspects, but it also considers the way the semantic information possibly associated to the groups of entities (nodes, faces) can be maintained. Such high level modification capabilities are of major importance in all the engineering activities requiring fast modifications of meshes without going back to the CAD model. This is especially true in the context of industrial maintenance where the engineers often have to solve critical problems in very short time. Indeed, in this case, the product is already designed, the CAD models are not necessarily available and the FE models might be tuned. Thus, the product behaviour has to be studied and improved during its exploitation while prototyping directly several alternate solutions. Such a framework also finds interest in the preliminary design phases where alternative solutions have to be simulated. The algorithm first removes the intersecting faces in an n-ring neighbourhood so that the filling of the created holes produces triangles whose sizes smoothly evolve according to the possibly heterogeneous sizes of the surrounding triagles. The holefilling algorithm is driven by an aspect ratio factor which ensures that the produced triangulation fits well the FE requirements. It is also constrained by the boundaries of the groups of entities gathering together the simulation semantic. The filled areas are then deformed to blend smoothly with the surroundings meshes

Merging enriched Finite Element triangle meshes for fast prototyping of alternate solutions in the context of industrial maintenance

A new approach to the merging of Finite Element (FE) triangle meshes is proposed. Not only it takes into account the geometric aspects, but it also considers the way the semantic information possibly associated to the groups of entities (nodes, faces) can be maintained. Such high level modification capabilities are of major importance in all the engineering activities requiring fast modifications of meshes without going back to the CAD model. This is especially true in the context of industrial maintenance where the engineers often have to solve critical problems in very short time. Indeed, in this case, the product is already designed, the CAD models are not necessarily available and the FE models might be tuned. Thus, the product behaviour has to be studied and improved during its exploitation while prototyping directly several alternate solutions. Such a framework also finds interest in the preliminary design phases where alternative solutions have to be simulated. The algorithm first removes the intersecting faces in an n-ring neighbourhood so that the filling of the created holes produces triangles whose sizes smoothly evolve according to the possibly heterogeneous sizes of the surrounding triagles. The holefilling algorithm is driven by an aspect ratio factor which ensures that the produced triangulation fits well the FE requirements. It is also constrained by the boundaries of the groups of entities gathering together the simulation semantic. The filled areas are then deformed to blend smoothly with the surroundings meshes

Physically based mechanical metaphors in architectural space planning

Physically based space planning is a means for automating the conceptual design process by applying the physics of motion to space plan elements. This methodology provides for a responsive design process, allowing a designer to easily make decisions whose consequences propagate throughout the design. It combines the speed of automated design methods with the flexibility of manual design methods, while adding a highly interactive quality and a sense of collaboration with the design. The primary assumption is that a digital design tool based on a physics paradigm can facilitate the architectural space planning process. The hypotheses are that Newtonian dynamics can be used 1) to define mechanical metaphors to represent the elements in an architectural space plan, 2) to compute architectural space planning solutions, and 3) to interact with architectural space plans. I show that space plan elements can be represented as physical masses, that design objectives can be represented using mechanical metaphors such as springs, repulsion fields, and screw clamps, that a layout solution can be computed by using these elements in a dynamical simulation, and that the user can interact with that solution by applying forces that are also models of the same mechanical objects. I present a prototype software application that successfully implements this approach. A subjective evaluation of this prototype reveals that it demonstrates a feasible process for producing space plans, and that it can potentially improve the design process because of the quality of the manipulation and the enhanced opportunities for design exploration it provides to the designer. I found that an important characteristic of this approach is that representation, computation, and interaction are all defined using the same paradigm. This contrasts with most approaches to automated space planning, where these three characteristics are usually defined in completely different ways. Also emerging from this work is a new cognitive theory of design titled 'dynamical design imagery,' which proposes that the elements in a designer's mental imagery during the act of design are dynamic in nature and act as a dynamical system, rather than as static images that are modified in a piecewise algorithmic manner

Numerical, Analytical and Experimental Analysis of Combined Extrusion Forging Processes Applied to Collet Chuck Holders

The material flow in the combined extrusion/forging process is an important phenomenon which controls the mechanical and metallurgical properties of any manufactured component. Collet chuck holder is a tool holding device used in different types of CNC milling machines. The chuck holder is described by a flange at the middle to fit into the machine, taper portion which is conical shaped area present at the bottom which enters the spindle for changing holder and collet pocket which fits the collet for holding the cutting tool. For manufacturing the tool holder an enormous amount of material is being wasted by the machining process which is almost equal to the volume of the product. Some manufacturer use casting, subsequently by machining to get the final shape. Both the used processes have their limitations as discussed earlier. To secure our material resources and to get better mechanical properties it is proposed to adopt the combined extrusion/forging and/or multi-stage processes for the production of different types of collet chuck holders. In general, it is found challenging to predict the metal flow by 3D combined extrusion/forging process of complicated sections, collet chuck holder in particular, due to its complexity nature of analysis. From experiments it is observed that the complete process to get the first three components can be assumed to compose of four stages and fourth one of two stages with regard to forward/backward extrusion, forging, die corner filling, and flash formation. The mechanical, microscopic, micro hardness and residual stress analyses are performed for all the four components manufactured under different frictional conditions and ram velocities. The results confirm the advantage of the proposed processes to manufacture collet chuck holder. In the present investigation, upper bound method is used to analyze the combined extrusion/forging process of different types of collet chuck holders. A set of kinematically admissible velocity field is proposed to predict the metal flow pattern and the forging load. This work also employed 3D finite element formulation to simulate the combined extrusion/forging process for axisymmetric collet chuck holders. The forming loads obtained by proposed upper bound technique is in good agreement with the numerical and experimental results and lies in the range of 0-15%, 5-20%, 0-15% and 12-20% for first, second, third and fourth products respectively. Experimental observations indicate that the collet chuck holder can be effectively manufactured by metal forming route of combined and/or multi-stage extrusion/forging to get its inherent advantages instead of following the present practice of machining and/or casting. The estimated loads obtained using proposed kinematically admissible velocity fields effectively take care of work hardening, friction effects and redundant work and are remain within engineering accuracy when compared with that obtained from FEA and experiments. The results confirm the suitability of the proposed techniques (FEA and upper bound) for the prediction of load in combined extrusion-forging processes studied in the present work applied to collet chuck holder

A Class of Solutions for Extrusion through Converging Dies

Extrusion, as a metal forming process, has definite advantages over rolling for production of three-dimensional section shapes. The very large reductions achieved in this process, even at high strain rates, have made it one of the fastest growing metal forming methods. With the increasing demand for sections of different shapes, it has become essential to develop analytical methods for their solution.The present investigation is a sincere attempt to develop a class of solutions for extrusion of different sections from round and square billet through converging dies by three-dimensional upper bound method as well as Finite element method. Three dimensional upper bound solutions are based on both continuous velocity field and discontinuous velocity field. The continuous velocity fields are based on dual stream function method. The discontinuous velocity fields are based on SERR (spatial elementary rigid region) technique.Upper bound method based on SERR technique is used for analysis of extrusion of pentagon, octagon, triangular and rhomboidal sections from round billet using linear converging die. The constant friction factor is assumed at the die billet interface. The single point formulation has been used keeping the die orifice in the centroid of billet axis so that product emerges straight. The extrusion pressure and die profile has been determined for different reductions and friction factors