Comparison Study of Mechanical Properties of Al-Si Alloy with and without Nanoreinforce Iron Oxide (Fe2O3)

Nanoreinforce materials such as ZnO, eggshell, Al2O3, TiO2, and ZrO2 have been shown to improve the mechanical properties of Al-Si alloy. Nanomaterial Fe2O3 has many applications as catalysts reaction in electronic devices, for example, semiconductor materials, paint formulations, lithium rechargeable batteries, and is often applied in industrial fields. It is known that Fe2O3 can be synthesized through the stirring process on machine and method used will involve several steps that relatively take a long time. In this study, Al-Si alloy reinforced by using nanomaterial Fe2O3 which sintered at a temperature of 600°C for 3 hours aimed to improve mechanical and morphological properties of Al-Si alloy. The method used was stir casting, where this method was known as flexible, simple, and economic. The result of reinforcing Al-Si alloy by using nanomaterial Fe2O3 had affected on the hardness level of Al-Si alloys as evidenced by the fracture morphology that was brittle and had a light reflectio

Investigation in situ des mécanismes d’endommagement dans un composite polyamide renforcé par des fibres courtes

Injection molded polyamide composite reinforced with short glass fibers has been widely used in automotive industry due to its high strength to weight ratio and the ability of injection process to produce complex parts. A reliable design of components made of this composite should consider the development of progressive properties degradation due to the damage. A better understanding of the damage mechanisms shall contribute to a better formulation of local damage criteria and thus to include with a higher accuracy the physical modeling of their effects to predict the overall mechanical behavior of the composite. For this purpose, in situ SEM tests were performed to observe the damage mechanisms of injection molded polyamide-66 reinforced with 30%wt of short glass fibers (PA66GF30). The observation was focused on dry as mold state (0% water content) of PA66GF30, which correspond to a relative humidity RH=0%. The specimens were subjected to a flexural load using a three-point bending micro-device and were assembled inside an environmental SEM to allow the in situ observations. Specimens were cut following two specific orientations with respect to the mold flow direction (MFD): longitudinal and transverse. Prior to observation, the surface samples were polished and metalized with gold. As the polyamide absorbs water during polishing, the samples were put after polishing inside a vacuum oven at 80 o C for 15h to ensure that the RH content goes back to zero in the whole sample

Multi-scale viscoelastic damage model of short glass fiber reinforced thermoplastics under fatigue loading

This work presents a new micromechanical fatigue damage model for reinforced thermoplastic composites. The study aims at modeling high cycle fatigue damage of a short glass fiber reinforced polyamide-66. The developed approach is a modified Mori-Tanaka method that includes coated reinforcements and microscale damage processes. The model takes into account the nonlinear matrix viscoelasticity and the damage mechanisms evolution. The latter is based on the experimental damage investigation previously performed by the authors and presented elsewhere. Damage chronologies have been proposed involving three different local processes: fiber-matrix interface debonding/coating degradation, matrix microcracking and fiber breakage. Each damage mechanism is introduced through an evolution law coupled to local stress fields computed at the microscale. The first numerical results show capability of the developed model to predict the fatigue damage accumulation of the macroscopic homogenized composite material

Analisis Sifat Mekanik dari Struktur Seluler yang Difabrikasi dengan Printer 3D

Struktur ringan berbentuk cellular (seluler) atau foam (busa) dalam beberapa tahun terakhir sangat banyak dikembangkan terutama karena perkembangan cepat dari Printer 3D, sehingga desain rumit dapat difabrikasi dengan mudah. Struktur seluler mempunyai rasio kekuatan terhadap massa dan kekakuan yang tinggi, serta dapat diaplikasikan pada struktur ringan dengan ketahanan impak yang tinggi. Dalam tulisan ini, dilakukan uji tekan terhadap enam jenis struktur seluler dengan fraksi volume 10%. Jenis struktur seluler yang divariasikan adalah Cubic, Gyroid, Honeycomb 3D, Rectilinear, Honeycomb, dan Rectilinear 45o. Hasil yang didapat menunjukkan bahwa struktur kompleks jenis Cubic mempunyai kekuatan maksimal terbaik dan juga mempunyai penyerapan energi yang terbaik berdasarkan pengujian yang dilakukan, diikuti dengan struktur Gyroid dan Honeycomb 3D. Struktur yang mempunyai topologi dua dimensi yaitu, Rectilinear 0o, Rectilinear 45o, dan Honeycomb tidak mempunyai kekuatan dan karakteristik penyerapan energi yang baik. Hasil ini dapat digunakan sebagai panduan desain struktur ringan yang mempunyai karakteristik kekuatan dan penyerapan energi mekanik yang tinggi

In situ damage mechanisms investigation of PA66/GF30 composite: Effect of relative humidity

Damage mechanisms of injection molded polyamide-66/short glass fiber 30 wt% composite (PA66/GF30) were analyzed using in situ SEM mechanical tests on specimens conditioned under three relative humidity contents (RH = 0%, 50% and 100%). The validity of these in situ analyses was confirmed by Xray micro-computed tomography (lCT) observations on tensile loaded specimens. Experimental results demonstrated that relative humidity (RH) conditions influence strongly the damage level and damage mechanisms. Indeed, for specimen with RH = 0%, damage initiation occurs at significantly higher load level than those in RH = 50% and RH = 100% specimens. The higher relative humidity condition also results in higher damage level. Damage chronologies have been proposed as damage initiation in the form of fiber–matrix debonding occurs at fiber ends and more generally at locations where fibers are close to each other due to the generation of local stress concentration (for all studied RH contents), and first fiber breakages occur (RH = 0%). These debonded zones further propagate through fiber–matrix interface (for all studied RH contents), and new fiber breakages develop (RH = 0%). At high relative flexural stress, matrix microcracks appear and grow regardless the RH contents. For RH = 100%, these microcracks are also accompanied by many matrix deformation bands. Subsequently, they lead to the damage accumulation and then to the final failure.Projet FUI-DGSIS "DURAFIP

Fatigue damage investigation of PA66/GF30 by X-Ray microtomography

Damage behavior of dry as molded, 30 wt% short glass fiber reinforced polyamide-66 (PA66/GF30) under fatigue loading has been investigated by X-ray micro-computed tomography (μCT). Based on visual observation on μCT images, fiber/matrix interfacial debonding is considered as the main fatigue damage mechanism. Void features in the shell and core layer of the μCT 3D images have been identified. The trend of void volume and void aspect ratio shows marked difference on the damage kinetic between the shell and core layer. Though the damage is mainly developed along fiber interface in both shell and core layer, the interfacial debonding in the shell layer appears earlier than the one in the core layer. While the damage at fiber interface in the shell layer develops in all fatigue loaded specimens, the interfacial debonding in the core layer appears only at the very last stage of the fatigue life

Fatigue damage investigation of PA66/GF30 by X-Ray microtomography

Damage behavior of dry as molded, 30 wt% short glass fiber reinforced polyamide-66 (PA66/GF30) under fatigue loading has been investigated by X-ray micro-computed tomography (μCT). Based on visual observation on μCT images, fiber/matrix interfacial debonding is considered as the main fatigue damage mechanism. Void features in the shell and core layer of the μCT 3D images have been identified. The trend of void volume and void aspect ratio shows marked difference on the damage kinetic between the shell and core layer. Though the damage is mainly developed along fiber interface in both shell and core layer, the interfacial debonding in the shell layer appears earlier than the one in the core layer. While the damage at fiber interface in the shell layer develops in all fatigue loaded specimens, the interfacial debonding in the core layer appears only at the very last stage of the fatigue life

Investigation in situ des mécanismes d’endommagement dans un composite polyamide renforcé par des fibres courtes

Injection molded polyamide composite reinforced with short glass fibers has been widely used in automotive industry due to its high strength to weight ratio and the ability of injection process to produce complex parts. A reliable design of components made of this composite should consider the development of progressive properties degradation due to the damage. A better understanding of the damage mechanisms shall contribute to a better formulation of local damage criteria and thus to include with a higher accuracy the physical modeling of their effects to predict the overall mechanical behavior of the composite. For this purpose, in situ SEM tests were performed to observe the damage mechanisms of injection molded polyamide-66 reinforced with 30%wt of short glass fibers (PA66GF30). The observation was focused on dry as mold state (0% water content) of PA66GF30, which correspond to a relative humidity RH=0%. The specimens were subjected to a flexural load using a three-point bending micro-device and were assembled inside an environmental SEM to allow the in situ observations. Specimens were cut following two specific orientations with respect to the mold flow direction (MFD): longitudinal and transverse. Prior to observation, the surface samples were polished and metalized with gold. As the polyamide absorbs water during polishing, the samples were put after polishing inside a vacuum oven at 80 o C for 15h to ensure that the RH content goes back to zero in the whole sample

Damage mechanisms in short glass fiber reinforced polyamide-66 under monotic and fatigue loading : Effect of relative humidity and injection molding induced microstructure

Le présent travail s'appuie sur une approche expérimentale étendue visant l'identification des mécanismes d'endommagement en chargement quasi-statique et en fatigue du PA66/GF30, en prenant notamment en compte l'influence de la teneur en eau et de la microstructure induite par le moulage par injection. Les essais et les observations in situ au MEB mettent en exergue le rôle déterminant de l'humidité relative sur l'initiation, le niveau et la chronologie de l'endommagement. Une analyse par micro-tomographie aux rayons X sur des échantillons ayant subi un chargement de fatigue montre que l'endommagement augmente continuellement et progressivement au cours de la fatigue, et plus significativement dans la deuxième moitié de sa durée de vie. Les résultats obtenus en quasi-statique et en fatigue révèlent des mécanismes d'endommagement similaires, notamment une décohésion des interfaces fibre/matrice. Une chronologie générale de l'endommagement est établie. Celui-ci s'initie en extrémités de fibres ou plus globalement là où les fibres sont relativement proches les unes des autres. Il s'ensuit des décohésions interfaciales se propageant le long des fibres. A une contrainte en flexion plus élevée, des microfissures de la matrice peuvent apparaître et se propager par coalescence, ce qui aboutira à la rupture. Ces résultats expérimentaux permettent d'alimenter une modélisation multi-échelles de l'endommagement à fort contenu physique. Celle-ci contribuera alors à une prédiction pertinente de l'endommagement dans les thermoplastiques renforcés pour application automobile.The current work focuses on extensive experimental approaches to identify quasi-static and fatigue damage behavior of PA66/GF30 considering various effects such as relative humidity and injection process induced microstructure. By using in situ SEM tests, it was observed that relative humidity conditions strongly impact the damage mechanisms in terms of their initiation, level and chronology. The X-ray micro-tomography analysis on fatigue loaded samples demonstrated that the damage continuously increases during fatigue loading, but the evolution occurs more significantly in the second half of the fatigue life. From the results of damage investigation under quasi-static and fatigue loading, it was established that both loading types exhibit the same damage mechanisms, with fiber/matrix interfacial debonding as the principal damage mechanisms. General damage chronologies were proposed as the damage initiates at fiber ends and more generally at locations where fibers are relatively close to each other due to the generation of local stress concentrations. Afterwards, interfacial decohesions further propagate along the fiber/matrix interface. At high relative flexural stress, matrix microcracks can develop and propagate, leading to the damage accumulation and then the final failure. The experimental findings are important to provide a physically based damage mechanisms scenarios that can be integrated into multiscale damage models. These models will contribute towards reliable predictions of damage in reinforced thermoplastics for lightweight automotive applications

Mécanismes d’endommagement du polyamide-66 renforcé par des fibres de verre courtes, soumis à un chargement monotone et en fatigue : Influence de l’humidité relative et de la microstructure induite par le moulage par injection

The current work focuses on extensive experimental approaches to identify quasi-static and fatigue damage behavior of PA66/GF30 considering various effects such as relative humidity and injection process induced microstructure. By using in situ SEM tests, it was observed that relative humidity conditions strongly impact the damage mechanisms in terms of their initiation, level and chronology. The X-ray micro-tomography analysis on fatigue loaded samples demonstrated that the damage continuously increases during fatigue loading, but the evolution occurs more significantly in the second half of the fatigue life. From the results of damage investigation under quasi-static and fatigue loading, it was established that both loading types exhibit the same damage mechanisms, with fiber/matrix interfacial debonding as the principal damage mechanisms. General damage chronologies were proposed as the damage initiates at fiber ends and more generally at locations where fibers are relatively close to each other due to the generation of local stress concentrations. Afterwards, interfacial decohesions further propagate along the fiber/matrix interface. At high relative flexural stress, matrix microcracks can develop and propagate, leading to the damage accumulation and then the final failure. The experimental findings are important to provide a physically based damage mechanisms scenarios that can be integrated into multiscale damage models. These models will contribute towards reliable predictions of damage in reinforced thermoplastics for lightweight automotive applications.Le présent travail s'appuie sur une approche expérimentale étendue visant l'identification des mécanismes d'endommagement en chargement quasi-statique et en fatigue du PA66/GF30, en prenant notamment en compte l'influence de la teneur en eau et de la microstructure induite par le moulage par injection. Les essais et les observations in situ au MEB mettent en exergue le rôle déterminant de l'humidité relative sur l'initiation, le niveau et la chronologie de l'endommagement. Une analyse par micro-tomographie aux rayons X sur des échantillons ayant subi un chargement de fatigue montre que l'endommagement augmente continuellement et progressivement au cours de la fatigue, et plus significativement dans la deuxième moitié de sa durée de vie. Les résultats obtenus en quasi-statique et en fatigue révèlent des mécanismes d'endommagement similaires, notamment une décohésion des interfaces fibre/matrice. Une chronologie générale de l'endommagement est établie. Celui-ci s'initie en extrémités de fibres ou plus globalement là où les fibres sont relativement proches les unes des autres. Il s'ensuit des décohésions interfaciales se propageant le long des fibres. A une contrainte en flexion plus élevée, des microfissures de la matrice peuvent apparaître et se propager par coalescence, ce qui aboutira à la rupture. Ces résultats expérimentaux permettent d'alimenter une modélisation multi-échelles de l'endommagement à fort contenu physique. Celle-ci contribuera alors à une prédiction pertinente de l'endommagement dans les thermoplastiques renforcés pour application automobile