Littérature scientifique sur le sujet « Pa66/gf30 »

Hybrid lightweight components with strong and reliable bonding qualities are necessary for practical applications including in the automotive and aerospace industries. The direct laser joining method has been used to produce hybrid joints of Ti6Al4V and glass fiber reinforced polyamide (PA66-GF30). Prior to the laser joining process, a surface texturing treatment is carried out on Ti6Al4V to improve joint strength through the formation of interlock structures between Ti6Al4V and PA66-GF30. In order to reduce the generated micro-pores in Ti6Al4V-PA66-GF30 joints, a modified laser joining method has been proposed. Results show that only very few small micro-pores are generated in the joints produced by the modified laser joining method, and the fracture strength of the joints is significantly increased from 13.8 MPa to 41.5 MPa due to the elimination of micro-pores in the joints.

Polymeric matrix composite materials presents advantages in a great number of applications due to their high specific strength and stiffness, wear resistance, dimensional stability, low weight and directional properties. As result of these properties and potentials applications exists a strong need to understand the manufacturing processes, particularly the machining process of these composite materials. This paper presents an investigation above the modelization of the cut, turning of small workpieces, on two materials: a polymer PA 6 (Polyamide) and a composite PA 66-GF30 (reinforced with 30% of glass fiber). The tests were carried out polycrystalline diamond tools (PCD). The objective of this experimental study is to evaluate the influence of the glass fiber reinforcement on the friction angle (ρ), shear angle (Φ), normal and shear stresses (σ, τ), chip deformation (ε) under the cutting parameters prefixed (cutting velocity and feed rate). The experimental model was compared with the theoretical model of Merchant.

This paper investigates the grinding process on unreinforced (PA66) and reinforced glass-fiber polyamide 6,6 (PA66 GF30) with Al2O3 and SiC abrasive wheels. Both materials were ground by varying rotations, workpiece infeed speed, depth of cuts for sequential roughing/finishing steps. Dry and liquid coolant conditions were also considered during the grinding process to evaluate the effects on part quality. The surface roughness was used to assess the quality of the final products with several parameter combinations, identifying the induced process trends. The results show that at the end of the finishing step, the surface roughness Rz was lower than 4 μm, attaining the lowest value of 1.34 μm for PA66 specimens. The analysis also suggested the choice of the Al2O3 grinding wheel to reach the lowest Rz values for both materials.

The paper presents a numerical analysis of thick-walled PA66 GF30 moldings with the addition of a chemical blowing agent with a content of 1-3 wt%, and the obtained results were compared with the real object. Computer simulations were performed using Moldex3D® software. Based on the numerical analysis, it was found that regardless of the dose of the blowing agent used, the largest pores were place in the core of the sample. Moreover, it was found that the size of the pores depends on their number in the cross-section of moldings. Compositions containing a higher cross-sectional pore density were characterized by smaller pore sizes. The results of the computer simulation also showed that increasing the blowing agent dose above 2 wt% does not significantly affect the size of the pores in the structure. The experimentally determined pore size of the composition containing 3 wt% chemical blowing agent slightly differs from the pore size obtained based on numerical analysis.

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.

Lightweight moldings obtained by microcellular injection molding (MIM) are of great significance for saving materials and reducing energy consumption. For thick-walled parts, the standard injection molding process brings some defects, including a sink mark, warpage, and high shrinkage. Polyamide 66 (PA66)/glass fiber (GF) thick-walled moldings were prepared by MuCell® technology. The influences of moldings thickness (6 and 8.4 mm) and applied nitrogen pressure (16 and 20 MPa) on the morphology and mechanical properties were studied. Finally, the microcellular structure with a small cell diameter of about 30 μm was confirmed. Despite a significant time reduction of the holding phase (to 0.3 s), high-performance PA66 GF30 foamed moldings without sink marks and warpage were obtained. The excellent strength properties and favorable impact resistance while reducing the weight of thick-walled moldings were achieved. The main reason for the good results of polyamide composite was the orientation of the fibers in the flow direction and the large number of small nitrogen cells in the core and transition zone. The structure gradient was analysed and confirmed with scanning electron microscopy (SEM) images, X-ray micro computed tomography (micro CT) and finite element method (FEM) simulation.

Le but de ce travail est d'étudier l'effet du vieillissement dans l'éthylène glycol et l'antigel sur le comportement global et les mécanismes d'endommagement du polyamide 66 (PA66) et du polyamide 66 renforcé par des fibres de verre courtes (PA66/GF). À cette fin, un dispositif expérimental de vieillissement adéquat est conçu et présenté pour conditionner les échantillons dans le glycol et l'antigel à différentes durées de vieillissement. L'effet d'absorption du milieu de vieillissement est analysé par le gonflement et la variation de masse (absorption). L'effet du refroidissement est également étudié en appliquant deux méthodes de refroidissement. Des essais de traction monotones sont effectués pour étudier l'effet du vieillissement sur le PA66 et le PA66/GF. Une investigation MEB (Microscope Electronique à Balayage) est ensuite réalisée pour caractériser les mécanismes d'endommagement et leur évolution en fonction de la durée de vieillissement. Des observations par tomographie à rayons X (µCT) sont également réalisées pour quantifier les dommages en fonction de la durée du vieillissement, du matériau et de la zone d'intérêt (AOI).Les résultats expérimentaux montrent que l'absorption de glycol et de l'antigel est plus importante pour la matrice PA66 non renforcée que pour le composite PA66 renforcé par des fibres de verre courtes. De plus, la rigidité, ainsi que la déformabilité du matériau, sont considérablement affectées par le vieillissement. En termes de dégradation du composite, les principaux mécanismes d'endommagement sont situés à l'extrémité de la fibre et à l'interface fibre-matrice, et pour les durées de vieillissement élevées, la cavitation dans la matrice polymère est constatée. L'étude par microtomographie à rayons X a indiqué que l'endommagement est principalement localisé au cœur et à la surface des échantillons, ce qui est dû à la microstructure cœur-peau bien connue des composites PA66/GF injectés. Toutes ces conclusions permettent de déduire l'effet significatif et irréversible du vieillissement du glycol et de l'antigel sur le comportement mécanique global et les mécanismes d'endommagement des matériaux étudiés
The aim of this work is to study the effect of ethylene glycol and coolant aging on the overall behavior and the damage mechanisms of the Polyamide 66 (PA66) and the short glass fiber reinforced polyamide 66 (PA66/GF). To this end, a proper experimental aging setup is designed and presented for conditioning the samples in glycol and coolant at different aging durations. The aging media absorption effect is analyzed through the swelling and the mass variation (uptake). The effect of cooling is also studied by applying two cooling methods. Moreover, monotonic tensile tests are performed to study the aging effect on the PA66 and PA66/GF. SEM (Scanning Electron Microscopy) investigation is then performed to characterize the damage mechanisms and their evolution with the increase of the aging duration. X-ray micro-computed tomography (µCT) observations are also carried out to quantify the damage depending on the aging duration, the material, and the area of interest (AOI).Experimental findings show that the glycol and coolant absorption is more important for the PA66 unreinforced matrix than for the short glass fiber-reinforced PA66 composite. In addition, the stiffness, as well as the material deformability, are found to be significantly affected by aging. In terms of composite degradation, the main damage mechanisms are the damage at the fiber's end and the fiber-matrix interface, and for the high aging durations, cavitation in the polymer matrix is observed. The X-ray µCT investigation has indicated pronounced damage mostly located at the core and surface of the samples, which is due to the well-known shell-core microstructure of injected PA66/GF composites. All these conclusions lead to inferring the significant and irreversible effect of glycol and coolant aging on the bulk mechanical behavior and damage mechanisms of the investigated materials

Polymer-metal hybrid (PMH) by over-molding is a kind of weight reduction technology, in which the interface is formed by injecting liquid polymer directly on the surface of stamped metal and then curing under pressure. This technique takes the advantages of both the high strength and stiffness of metal and the complex geometry formability of polymer, and it is usually applied in structural components for weight reduction compared to all-metal structure. However, the different coefficient of thermal expansion (CTE) or hygroscopicity for polymer and metal in PMH structure may possibly produce additional interface stress and decrease joining strength degradation, and finally lead to local separation or complete fracture under various environmental loads. The present paper will provide an effective numerical method and investigate the influence of temperature and humidity on the onset and growth of crack, as well as the degradation of interface fracture toughness in PMH structures. Additionally analytical analysis provides qualitative guidelines and orientation for numerical method. The crack initiation is studied by the tensile test of a lap joint specimen, and the crack growth is studied by the DCB (Double Cantilever Beam) test and ENF (End Notched Flexure) test and of PMH specimen with an initial crack. It proves that both temperature and humidity has a great influence on interfacial strength, ultra bearing capacity and energy release rates of PMH structures, and their coupling has more influence than a single factor. The interface degradation degree of the GF30/PA66-HSS is lower than that of PA66-HSS under the same hygrothermal environment.