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Without packaging, it would be very difficult to distribute consumer goods. The packaging protects the merchandise during shipment, informs the user about the product, extends the life of the product, and last but not least, it helps the economy and the recycling process, especially with the latest trend on being environmentally friendly. A packaging box should confer mechanical protection when manipulating the product, but also should be economically feasible when it comes to production costs. The packaging material that meets the above criteria is cellulose. “Packages made from corrugated cardboard are products made from renewable raw materials, which can be optimally integrated into production cycles”[1]. Design packaging takes into account factors like manipulation, shipping, distribution, and product marketing by using graphics and information printed on the package. As a result of this, packaging designers are looking for solutions that make the packaging life cycle optimal and feasible when taking into account factors like mechanical strength, chemical, climatic and biologic

Over time, companies have prioritized the management of money, materials, equipment and people. Today, in such a globalized environment, they have come to recognize the paramount importance of quality, price, fast product delivery, flexibility and a continuous process of innovation. This is where additive manufacturing comes into play as one of the newest and most promising improvement solution for the above mentioned components of the industry. This paper will provide an understanding of the additive manufacturing technologies, analize them in comparison to the traditional machining techniques, emphasizing their application fields and their limitations and will present the various types of said technologies. There is still a lot of work and research to be done until additive manufacturing technologies overtake the manufacturing world but the continuous growth and successful results that have been seen since the beggining show the great undeniable potential that these technologies have.

The article presents a promising technology for medical applications - additive technology by thermoplastic extrusion. Some conceptual models for knee prostheses of different constructional forms have been made using FDM technology. Different materials, including biocompatible, were considered and different 3D printing equipment was used to choose the variant with the most optimal characteristics. These conceptual models can have various beneficial applications in medicine, improving the quality and functionality of personalized prostheses.

Colloque avec actes et comité de lecture. Internationale.; International audience; Some tribological phenomena concerning the friction behavior of metallic or non-metallic materials at lower values of sliding speeds are essentially different from those corresponding to high speeds. Based on previous experimental and numerical studies developed in the GCGM laboratory of INSA Rennes concerning bulk and surface anisotropy of metallic thick plates together with their mechanical behavior evolution under important thermo-mechanical loading gradients, this scientific paper proposes to study the influence of a rolled thick sheet aluminum anisotropy on the stick-slip phenomenon concerning a range of low and very low sliding speeds (0.2-200 mm/min). It is known that the stick-slip phenomenon occurs if the static friction coefficient has a larger value as compared to the kinetic one, especially in the case of friction couplers with a dry or a limited friction regime (when the sliding speed is in the range of 0.01-3 mm/s or when the angular speed is somewhere in the range of 1-25 rad/s). For this study it was used an UMT Micro-Scratch Equipment of the Machine Elements and Tribology Department (OMTR)- University Politehnica of Bucharest (UPB). The equipment can provide rotational, translational or reciprocating motions with speeds starting from 0.1?m/s up to 10m/s. A constant or a progressive normal load between 0.05 N and 1000 N can be applied on the material sample. Experimental friction tests were made on an anisotropic rolled aluminum alloy AA2024-T351 using an ultra-high-molecular-weight polyethylene (UHMWPE) cylindrical pion. The AA2024-T351 is one of the most popular high-strength aluminum alloys, having a low corrosion resistance and good mechanical properties at high temperatures: ultimate tensile strength > 420 N/mm2, yield strength at 0.2% > 260 N/mm2, HD harshness around 120 Kgf/mm2, LF 108 cycles of 125 MPa, Young modulus 71000-74000 MPa and Poisson coefficient of 0.33. The ultra-high-molecular-weight polyethylene is characterized by an excellent resistance to abrasion and its main mechanical properties are defined by a ultimate tensile strength around 231.1 MPa, a yield strength of 25.6±3.3 MPa, a Young modulus 915±42.3 MPa and a Poisson coefficient of 0.46. All the tests have been performed by moving the polyethylene pion along a specified trajectory under a constant normal force and at a uniform sliding speed. In order to analyze the influence of the aluminum alloy anisotropy, the tests were made along the three directions: a longitudinal one, corresponding to the rolling direction of the sample (0°), a transverse one, which represents the direction perpendicular to the rolling direction (90°), and a median direction (45°). Three different normal forces (3N, 5N, 7N) have been applied corresponding to three different sliding speeds (0.005 mm/s, 0.05 mm/s, 0.5 mm/s) along a specified trajectory of 3 mm length. It was observed that for a speed of 0.005 mm/s the friction coefficient decreases if the force increases for all the three principal anisotropic directions. When the sliding speed is increased up to 0.5 mm/s, the friction coefficient remains constant. It can be seen that the friction coefficient has different values along the three loading directions (longitudinal, transversal or median): the highest friction coefficient occurs for the direction perpendicular to the rolling direction and the lowest for the rolling direction. However concerning the median direction, the corresponding friction coefficient has little change with the sliding speeds or the normal forces. Specific theoretical and numerical analysis will be performed concerning the bulk and surface anisotropy of studied aluminum plate, especially regarding the influence on the tribologic properties and corresponding friction model formulations.

Noise and vibration analysis has become thoroughly researched in vehicle engineering where is needed to keep the noise level low and affect the vehicle users. The analysis in the paper shows a frequency response study where we will determine the frequency response on a coupled structure-fluid model. The study will be made on a simplified “train wagon“ model to show in a better way the differences between a perfect coupled structure-fluid model and a non-conformal coupling. The analysis shows that the distribution of the nodes for the two cases influences the results.

The complex loading paths of non-conventional or rapid forging processes, especially as regards the important gradients of the plastic strain and strain rate characterizing the material deformation, require a reliable knowledge of the rheological constitutive equations. Some recent studies propose adequate phenomenological formulations taking into account the corresponding local physical mechanisms and the sensitivity of the true stress with respect to all mechanical variables. At the same time important scientific efforts have been focused in order to identify correctly all the constitutive law parameters, using adequate mechanical tests and robust numerical tools based generally on the inverse analysis principle. It is known that this new method requires building of a rigorous and adequate experimental space, using data obtained from loading conditions close to the industrial forming process. Then to explore high variations of plastic strain and strain rate, one of the most suitable tests are based on high speed hydraulically press and on the Split Hopkinson Pressure Bars test (SHPB). Consequently this paper propose to improve the experimental data accuracy obtained from the SHPB device by using finite element simulations of the entire high speed mechanical experiment together with the description of the inverse analysis strategy applied in order to analyze the thermo-mechanical constitutive behavior of metallic materials behavior and to identify the corresponding rheological parameters. The first part of this study will be dedicated to a short description of the experimental SHPB test analysis and to the analysis of the measurement data which can be used to describe the real mechanical loadings of the specimen. A new experimental calibration method of the acquisition signals, based on the finite element modeling of the elastic bars deformation during an impact without specimen, will be detailed. Using ABAQUS and CAST3M software, this method is validated from the comparison of the elastic strains variation obtained by the numerical simulations. In a second part will be detailed the inverse analysis strategy together with a real application concerning the rheological behavior of an aluminum alloy using a “dumbbell” specimen during a high speed upsetting test starting from a proposed constitutive relationship. Finally, special “cap” geometries of the material sample will be analyzed during a SHPB compression test in order to understand the feasibility of the proposed method to expand the material constitutive behavior identification to severe loadings. It is then shown the capacity to describe deformation path close to the rapid manufacturing processes and high speed machining.

Colloque avec actes et comité de lecture. Internationale.; International audience; L’objectif de ce travail est de réaliser une étude sur la diminution du risque du flambage en élasticité et plasticité lors des opérations de formage volumiques. Certains outillages de forgeage, comme les appuis, les poinçons ou les éjecteurs, présentent de risque de flambage en service, surtout dans le domaine des déformations élastiques. Cependant les pièces subissent lors des opérations de forgeage des grandes déformations plastiques, présentant aussi un risque important de flambement. Actuellement il existe des abaques définissent les rations à respecter pour éviter ce risque, mais les limites d’utilisation ne sont plus connues et les extrapolations sont difficile à être réalisées. Généralement les charges critiques de stabilité peuvent être déterminées en utilisant des méthodes approchées basées sur des méthodes énergétiques ou par la prise en compte des imperfections. Ainsi l’analyse théorique du flambement des poutres comprimées se fonde en tout premier lieu sur l’étude fait par Euler, à partir d’un modèle analytique basé sur un comportement élastique, du matériau et de celui des barres, de type loi de Hooke. La littérature indique ainsi que le flambage peut-être étudié en utilisant la courbe de variation de la contrainte critique avec le facteur d’élancement. Partant des courbes empiriques de type Tetmayer – Iasinski ou Johnson, établies expérimentalement, on peut caractériser le flambement élastique, élasto-plastique et plastique. Dans cette étude on propose un modèle de caractérisation du flambement élasto-plastique en partant du celui de Johnson, mais en utilisant une variation linéaire par une droite tangente raccordée à l’hyperbole d’Euler dans le point d’élancement critique lui correspondant. Ce modèle sera validé par des résultats expérimentaux et des simulations EF (sur CAST3M et ABAQUS). Pour l’estimation de la charge critique on utilisera la courbe de variation de la force longitudinale avec le déplacement transversal, en identifiant le point critique de sollicitation caractérisant l’instabilité de flambement.

In the last years there is an increasing demand for the efficiency, compact size, low noise level and reliability of gear transmission. This imposed that gear designers use adequate software for design and verify the product development. The paper aims to evaluate the use of different software for design and test the spur gear transmissions. An algorithm from the concept and geometric profiles of the teeth and linked parts to the models obtained using Finite Element Analysis (FEA) which aims to test and verify the comportment of the involved structures in the meshing process is presented. The paper aims also to demonstrate that ISO or other standards cannot conduct a reliable analysis of the root tooth bending and teeth contact stress. The proposed algorithm shows that o lot of software can be used but also the necessity to generate specific codes to interlink the steps in the algorithm. Also the paper put in discussion the use of 2D and 3D models in the transmission design process. One feature of the algorithm is the necessity of the 3D model in the process. The use of FEM as a numerical method to evaluate the behavior under static load conditions is also one of the necessity in the modern conditions of product development and the paper aimed to demonstrate that feature. Finally the presented FEM software shows a complete suitability for the calculation of spur gears transmission and not only.

The goal of present paper is to describe some aspects regarding the mechanical properties of the lead-free solder joint connections obtained by using the vapor phase soldering technology. In order to highlight the mechanical properties of solder joints in correlation with different pad finishes and different solder paste composition, there were performed some mechanical tests using a Share test system. Novelty is that the paper presents a mechanical experiment that wants to describe the adhesion of solder joint on cooper pad. The experiment was performed using two types of solder paste and three types of pad finish.