Search results for "Finite element"
showing 10 items of 892 documents
Theoretical approaches for modelling buckling effects in rebars of RC members
2017
Buckling of longitudinal bars in reinforced concrete (RC) members is definitely a critical issue in framed structures subjected to seismic loads. Second order effects can affect the compressive stressâstrain law of steel bars, influencing ductility calculations of RC structures. Moreover, literature studies show that buckling can occur over a length wider than stirrupsâ pitch (global buckling mode), involving more stirrups and inducing large deflections in the bar. If the critical length is not carefully estimated, stirrupsâ failure can occur, causing also the sudden loss of confining effects in concrete. This paper presents the results of different approaches for calculating the crit…
A New Friction Stir Welding Based Technique for Corner Fillet Joints: Experimental and Numerical Study
2010
Friction stir welding (FSW) is an energy efficient and environmentally "friendly" (no fumes, noise, or sparks) welding process, during which the sheets are welded together in a solid-state joining process. FSW is mature for simple configurations but a significant lack of knowledge is found when dealing with different designs such as T-sections, corner welds and box sections. The present work explores the feasibility of producing corner fillet geometries using FSW. Although such a kind of geometry has traditionally been considered unfeasible for the process, it seems to have a great potential to be used for T-joint configurations, a recurrent design pattern in transport applications. A speci…
Obtaining the electrical model of a power transformer by means of finite element software
2005
Abstract. The behaviour of transformers and inductors working at high-frequencies and high power density can dramatically differ from the ideal or low-frequency operation. Their performance is very dependent on the magnetic material, operating frequency and physical construction. In this paper, finite element analysis (FEA) is used to obtain an accurate characterization of the electromagnetic behaviour of these magnetic components.
Lay-up optimization for the hull of a racing sailing yacht
2001
Abstract Deformability and buckling load of yacht hulls with fiber reinforced plastic sandwich structure depend on the stack sequence of the skins. In this work an optimization of fiber directions of the laminae for a racing yacht is proposed. This procedure has been divided into three parts (i.e. material characterization, surface model definition, lay-up optimization). First of all a set of unidirectional specimens has been realized, by using the same fibers and matrix (carbon/epoxy) used for the hull as well as the same procedure and workers, in order to characterize the material according to American Society for Testing and Materials (ASTM) Standard D3039, employing strain gage techniqu…
Application of a decision making method to improve an industrial hot extrusion forging process
1999
Abstract Success of a bulk forming process is significantly affected by several operative parameters, such as dies and workpiece temperature, friction factor, preformed dimensions and its initial positioning. In the paper the hot extrusion forging of an half shaft of a two stroke motorcycle engine has been investigated. The combined effect of the most influent operative parameters has been determined by means of a consistent factorial plan. A sensitivity analysis was performed using an advanced numerical finite element code as a powerful CAE tool able to assist the analyst in the design of the process. The geometry of the part has allowed a combined 2D-3D numerical analysis; in fact, the in…
A finite/infinite element analysis of thick plate on a layered foundation
2000
Abstract The algorithm of calculations of a thick plate on the Kolar–Nemec's subsoil by the finite/infinite element method is presented. The layered subsoil numerical implementation different from that given by Kolar and Nemec is proposed. The advantages of employing the proposed algorithm to the solutions of plates on layered foundation are then illustrated by numerical example.
Development and validation of a nonlinear dynamic impact model for a notch impact
2015
Finite element simulations are being more and more applied when studying the crash-worthiness of vehicles during impact. This paper deals with setting up such a simulation and discusses several ways to simplify and verify a simulated crash. For this purpose, a notch impact-testing machine will be released from a certain angle and crash into a model constructed with three different wall thicknesses. The plastic and elastic deformation is measured in the front of the model and is then used for validation of the simulation. In the end, the simulation was found to be in good agreement with the real crash data.
Shape Distortion and Thickness Distribution during SPIF Processes: Expermental and Numerical Analysis
2011
Single Point Incremental Forming (SPIF) is a quite new sheet forming process which offers the possibility to deform complex parts without dedicated dies using only a single point tool and a standard 3-axis CNC machine. The process mechanics enables strains much higher than traditional sheet forming processes, but particular attention must be given to the final part geometrical accuracy. In this paper the capabilities of a dedicated explicit numerical model are quantitatively analyzed on pyramid-shaped parts. In particular a comparison between experimental and numerical results is reported. Three different shapes at the varying of the stamping angle were considered and the final shape was ac…
Optimal Blankholder Force Path in Sheet Metal Forming Processes: An Al Based Procedure
1999
Abstract Blankholder force plays a fundamental role in the deep drawing process mechanics since it controls, by friction, the material flow into the die cavity. The availability of computer controlled hydraulic presses in the industries promoted a new research field focused on the definition of optimal BHF histories, function of the punch displacement; such studies were aimed to the determination of the so called “process window”, i.e. the BHF path which permits to obtain the maximum height sound component avoiding both wrinkling and tearing. In the paper a design procedure is proposed in order to determine the optimal BHF path in an axisymmetric deep drawing process: in particular, a close…
On the material flow in fsw of T-joints: influence of geometrical and tecnological parameters
2008
Friction stir welding (FSW) now definitively reached a large interest in the scientific community and what is more in the industrial environment, due to the advantages of such solid state welding process with respect to the classic ones. The latter aspects are relevant also with reference to joints characterized by a complex geometry. What is more, advanced FEM tools permit to develop effective engineering of the processes; quantitative results can be acquired from numerical simulations once basic information, as the process mechanics and the material flow, are certain. Material flow plays a fundamental role in FSW since it determines the effectiveness of the joints or, in turn, the insurge…