Wire Arc Additive Manufacturing (WAAM) is revolutionizing the field of Additive Manufacturing (AM) by being the technological solution to manufacture thin-walled structures of large dimensions and medium geometric complexity at reduced cost with an excellent buy-to-fly ratio. Manufacturing parts with this technology is nowadays done through 2.5D strategies. This type of strategy consists in cutting a 3D model using planar layers parallel to each other. This 2.5D technique limits the complexity of the geometries that can be produced in WAAM without taking advantage of height deposit modulation. It also requires several start/stop phases of the arc during the transition from one layer to another, which leads to poor quality. This paper presents a new fast and efficient path planning strategy aiming at creating a continuous manufacturing path, thus increasing poor part quality. This strategy so called "Scalar Thermal Field for Continuous Toolpath" is generating a continuous spiral manufacturing toolpath for thin shaped parts. The modulation of deposition, by controlling the welding torch travel speed at constant wire feed rate, allows continuous deposition of material throughout the manufacturing process. The keypoint of the method is the use of a thermal scalar field associated with a 6-axis robotic arm kinematics which allows the manufacturing of closed parts after optimal closure point determination or direct manufacturing of opened parts with non-planar free edges. Validation of the presented method is performed by manufacturing three distinct parts : an opened, a closed part and a multi-branch part. The fabrication of these parts and their precise measurement have shown the reliability and the restitution capacity of our method which is clearly superior to 2.5D strategies nowadays commonly used in WAAM technology.

Pellets are spherical agglomerated particles used to produce multiparticulate pharmaceutical dosage forms. This study aims to develop a new approach that evaluates the deformation behavior of pellets under compression, by combining tableting data and compression models with X-ray micro computed tomography (XMT) image analysis. The deformation of Microcrystalline cellulose (MCC) and sugar pellets known to have different deformation behavior under compression was investigated. Compression data and modeling confirmed the plastic and brittle behavior for MCC and sugar pellets respectively. Image analysis of the XMT showed a different evolution of the morphometric parameters: structure thickness diameter (St Th) and volume equivalent sphere diameter (ESDv). The brittle sugar pellets showed a decrease in both ESDv and St Th parameters while plastic MCC pellets showed a decrease in ST Th and a constant ESDv which is coherent with ductile and brittle material deformation. This study shows that XMT can be used as a tool to characterize the mechanical behavior of pellet particles during compression

The paper presents the impact of thermal cycling frequency on the lifetime of IGBT power module. The first part will be devoted to a quick presentation of the test bench. Then, the test protocols will be detailed as well as the measurement protocol to characterise the ageing of the power module wirebonds. An important part will be devoted to the results of ageing. Before concluding, mechanical tensile tests on bondwires will complete the ageing tests.

Significance Nanoporous carbon texture makes fundamental understanding of the electrochemical processes challenging. Based on density functional theory (DFT) results, the proposed atomistic approach takes into account topological and chemical defects of the electrodes and attributes to them a partial charge that depends on the applied voltage. Using a realistic carbon nanotexture, a model is developed to simulate the ionic charge both at the surface and in the subnanometric pores of the electrodes of a supercapacitor. Before entering the smallest pores, ions dehydrate at the external surface of the electrodes, leading to asymmetric adsorption behavior. Ions in subnanometric pores are mostly fully dehydrated. The simulated capacitance is in qualitative agreement with experiments. Part of these ions remain irreversibly trapped upon discharge.

The aim of this paper is to describe the dynamic behavior of biaxial glass fiber reinforced laminate composites under low velocity impact test through finite element modelling. Experimental investigations by impact test performed using an instrumented drop weight testing machine were conducted on three-point bending composite samples in order to assess their impact damage resistance. Moreover, the experimental setup allowed the visualization of real-time damage progression of the impacted laminate composite via high-speed camera Phantom V2512 enabling to capture 83000 frames per second. Dynamic strain fields were extracted by Digital Image Correlation (DIC) method. Based on the experimental results, a numerical study of the impacted specimens was developed as a user subroutine VUMAT integrated to ABAQUS/Explicit in order to precisely capture the progressive dynamic failure of the laminate composite under impact test. In the proposed model, the damage and failure of each ply are accounted by a Hashin 3D damage-based behavior, and a cohesive zone model is employed to capture the onset and progression of inter-laminar delamination. A good experimental-numerical correlation was obtained for peak force and failure modes.

The use of fiber reinforced composites has increased in naval construction due to their favorable physical properties in particular their specific modulus, ease of fabrication and excellent mechanical behavior in the marine environment. As such, sandwich materials, composed of two laminated facings and a polymer foam core, are the first-choice materials for the design of light and rigid superstructures for the vessels. The purpose is to study and model the mechanical behavior of sandwich materials made of recycled and bio-based materials (biopolymers reinforced by low environmental impact fibers) in the nautical construction, since they can offer equivalent specific mechanical properties compared with traditional composites, while having better environmental credentials. In order to establish a homogenized behavior of a sandwich material, the work is divided into two parts: the characterization of the foam and then of the bio-based composite. The first part consists of studying the mechanical behavior of a reference foam of polyvinyl chloride (PVC) and those of recycled polyethylene terephthalate (PETr) substitute foams. The evaluation of the behavior of a foam-model is complicated as a result of the anisotropy induced by the process and the structural heterogeneity at the scale of laboratory tests. Compression and shear tests, instrumented by a Digital Image Correlation method, were conducted on different shapes and dimensions of PVC and PETr foams in order to identify the mechanical parameters and thus, lead to measurements of apparent properties. Following the compression tests, PVC and PETr foams are found to be transversely isotropic. Using these experimental results, the elastic mechanical behavior of PVC and PETr foams is identified based on a finite element model updating method, using Abaqus and Matlab, by minimizing the difference between the simulated modulus, and the experimental apparent elastic one.

Carbon fibre reinforced composites (CFRC) are finding more and more applications to replace conventional materials in many fields such as recreational boatbuilding. This increasing demand is justified by their excellent mechanical properties at lower densities and their corrosion and fatigue resistance. The current global environmental and economic challenges together with the increasing restrictive legislation are driving the development of new sustainable routes towards better environmental footprint of composites. Recently developed liquid thermoplastic resins could represent good candidates to replace thermoset resins in boats construction. They may offer the possibility to recover raw materials from retired parts. A first proof of concept of recovery and reuse of both reinforcement and matrix from a carbon fibre reinforced acrylic thermoplastic composite by pyrolysis is presented in this work. Reclaimed clean carbon fibre as well as recycled matrix were used to remanufacture semi-recycled and fully recycled good quality composites by resin infusion with around 55% fibre volume fraction. The morphological study at fibre scale resulted in concluding that sizing has been decomposed during depolymerisation process. Mechanical properties were retained after recycling compared to reference material. The changes were less than 3% for the tensile modulus and 4% for tensile strength. The same trend was found by dynamic mechanical analysis, with some clear similarities between virgin and recycled Elium resin. Interlaminar shear analysis highlighted a significantly enhanced interfacial strength compared to reference material.