This work investigates the critical plastic strain variation with stress triaxiality and the Lode angle parameter for an Acrylonitrile butadiene styrene (ABS)-based proprietary blend compound (commercial name VeroWhitePlus™ RGD835) manufactured through photopolymerization. Various triaxial states of stress and Lode angles were obtained with the help of notched flat specimens used in tensile loadings, notched round specimens used in compression (upsetting) tests and butterfly specimens used in Arcan tests. The tests were replicated using finite element analyses in order to evaluate the aforementioned parameters.

In this article, the yielding and plastic flow of a rapid-prototyped ABS compound was investigated for various plane stress states. The experimental procedures consisted of multiaxial tests performed on an Arcan device on specimens manufactured through photopolymerization. Numerical analyses were employed in order to determine the yield points for each stress state configuration. The results were used for the calibration of the Hosford yield criterion and flow potential. Numerical analyses performed on identical specimen models and test configurations yielded results that are in accordance with the experimental data.

In our previous research work, we investigated different methods to mitigate the vortex rope that appears in the draft tube of a Francis turbine when it operates at off-design operating points. The most promising results were obtained for a method involving an axial jet of water. The minor disadvantage of this method was the high value of the flow rate of the water jet. Our present work focuses on another method that decreases the value of the flow rate of the jet. In this sense, a new device has been developed that produces a pulsating water jet, which mitigates the pressure fluctuations associated with the swirling flows. The objective of this paper is to use our experimental test rig to validate the efficiency of a pulsating water jet in mitigating the vortex rope. To perform that, pressure measurements were carried out at four test levels to evaluate the pressure amplitude evolution when the pulsating jet was deployed. From preliminary investigations, the results indicate that this method leads to a decrease of the pressure amplitude of the vortex rope, with a lower value of the flow rate of the jet.

The part cost optimization is one of the major problems in plastics industry. The designers must take into account a lot of aspects regarding the functional role of the part, the mechanical loads, and least but not last, the part cost. The part cost depends on the mould cost, the equipment operation cost and the material cost. The paper presents a methodology to estimate the part cost, focusing on the equipment operation cost. In addition, a spreadsheet is provided in order to estimate the equipment operation cost.

During metal machining, under certain conditions, vibrations occur, both at the cutting tool, at the workpiece and at the machine tool. The appearance of vibrations during the cutting process is troublesome, because vibrations reduce the durability of cutting tools (especially in tools with inserts). It also increases machine tool wear and worsens the quality of the machined surface (roughness). The problem of vibration is vast and will represent a permanent research topic for tool makers, machine tool builders and process engineers. This paper presents the study and finite element analysis of the vibrations of a cutting tool, a tool used in the longitudinal turning process, both for deburring and finishing operations. The behavior of the tool, the natural frequencies and the elastic deformations that lead to the impairment of the processing precision and the quality of the surface obtained after processing were demined by calculation. We believe that this study is useful both to the manufacturers of cutting tools, but especially to the technological engineers, for the optimization of the process, by avoiding the cutting parameters that lead to resonance with the tool's own frequencies.