Adrian Pascu

The Influence of Geometrical Parameters on the Incremental Forming Process for Knee Implants Analyzed by Numerical Simulation

In this paper the authors intend to examine by numerical simulation one of the newest methods for obtaining the knee condylar surface, namely by incremental forming starting from a commercially pure titanium (CP Ti) sheet. In order to study the influence of the geometrical parameters, the authors chose to vary the material thickness, the punch diameter and the vertical step of the punch. Two different values of the hemispherical punch diameter (d = 4 and 6 mm), two different initial thicknesses of the blank (t = 1 and 1.2 mm) and two different vertical step values (s = 0.6 and 1 mm) are taken into consideration. The numerical results of the simulations were centered on determining the thinning of the sheet, the major principal strain, the springback, the process forces and the manner in which these are influenced by the geometrical parameters that were varied.

Experimental Method for Determining Forces at Bending of Perforated Plates

Abstract This paper describes the method of calculating the forces which appear at the bending of perforated plates with holes of different shapes and placed in different patterns, by means of a dynamometric table which uses resistive tensometric transducers (strain gauges). It also describes an instrument for the recording of data from the dynamometric table, a tool created with the aid of the “TestPoint” software which, beneath the data recording, ensures the filtering and statistic processing of data. The obtained results are displayed in comparative graphs for six types of perforated plates, as well as for an unperforated plate.

Generalized Modelling of the Stabilizer Link and Static Simulation Using FEM

Abstract This paper proposes an organological approach of one of the components of front suspension, namely anti-roll power link. There will be realized a CAD 3D modelling of this power link. 3D modelling is generalized and there were used the powers of Catia V5R20 software. Parameterized approach provides a high flexibility in the design, meaning that dimensional and shape changes of the semi-power link are very easy to perform just by changing some parameters. Several new versions are proposed for the anti-roll power link body. At the end of the work, it is made a static analysis of the semi-power link model used in the suspension of vehicles OPEL ASTRA G, ZAFIRA, MERIVA, and constructive optimization of its body.

Experimental Study Regarding of Bending Behaviour of Stabilizator Link

Abstract This paper presents an experimental study of the behavior of anti-roll power link subjected to bending, power link coming from an Opel Astra G. The power link is made of PA66 GF30 polyamide. For this study, there were used a universal testing machine (Instron 5587) and a real-time strain measurement optical system (Aramis). The results showed are those obtained in the case of a compression force of 1,000 [N] namely: major Strain ε1, minor strain ε2, equivalent von Mises strain, displacement on X axis, displacement on Y axis (compression force direction), displacement on Z axis.

Experimentally Testing the Polyethylene Pipes upon Being Strained with the Squeeze – Off Tool

The present paper aims at monitoring the behavior of the high density polyethylene pipe when pressed by an external force in order to shut it off so that the natural gas can no longer pass through the distribution pipelines. The behavior of the polyethylene pipe will be observed by means of fast shutter cameras, and the mechanical tests will be conducted by using the squeeze-off tool. Keywords-mechanical test; polyethylene pipe; rapid photography

Comparative Study for Springback Prediction on Single Point Incremental Forming Process

The present paper proposes a comparative study in order to determine the springback in single point incremental forming process. Using the Ls-Dyna software the process was simulated for one piece in frustum of pyramid shape. In the end of the explicit dynamic analysis, it was run, using the same software, an implicit analysis to determine the springback. For this comparison study we selected four different shell formulations. The results obtained in this simulation were compared with those obtained experimentally for the same part. The experimental research was conducted on a robot and, on the opposite side of the machined surface, an Aramis measuring optical system was placed to allow the online determination of deformations, displacements and thinning of material. Also, using this system, the springback was determined at the end of forming process. The closest values were obtained when using fully integrated formulation with thickness-stretch with 11 integration points on material thickness.

Experimental Determining of Mechanical and Elastic Characteristics for the Material Used in the Manufacturing of Cardan Crosses

The paper presents in its first part the need for analysing the functioning of the cardan cross within the cardan transmission, both from the point of view of shape and from the point of view of the material. In the second part there are described the main elements for analysing the test samples, the employed testing machine, as well as the manner of processing the obtained information. The last part contains the conclusions resulted from this analysis..

Theoretical and Experimental Studies on the Influence of Process Parameters on Strains and Forces of Single Point Incremental Forming

These paper aims to determine the influence of the most important geometrical parameters (vertical step and punch diameter) on the main strains, thickness reduction and the forces along two directions during the single point incremental forming process (SPIF). The paper comprises a comparative numericalexperimental study, for a simple geometry part obtained by incremental forming. In fact, in the first stage, the punch has a vertical motion with the value of one vertical step. In the second stage, the punch follows a linear trajectory along one side of the die. After each linear trajectory the punch has successive vertical motions, taking one vertical step at a time until the entire geometry of the part is done. In order to study the influence of the geometrical parameters, to the vertical step and the punch diameter were assigned three levels of variation. Following the selection of these geometrical parameters values, a factorial experimental program of type 32 has been adopted. The maximum values of the main strain and thickness reduction rises with the decrease of both vertical step and punch diameter and the maximum values of the forces are reached with the increase of both vertical step and punch diameter.

Numerical-experimental comparison study regarding single point incremental forming process

The paper presents a comparison study based on the numerical simulation with the finite element method (using the Ls-Dyna software) of incremental sheet metal forming and experimental researches regarding the same process. For this comparison study we selected four different shell formulations: Belytschko-Tsay (shell formulation number 2), fully-integrated shell formulation (shell formulation number 16) and two relatively new shell formulations Belytschko-Tsay with thickness-stretch (shell formulation number 25) and fully integrated with thickness-stretch (shell formulation number 26). In order to compare the results of the numerical simulations with the results of the experimental researches we focused on the maximum values of the mains strains, the thickness reduction and the forces on two directions.