Les lignes de soudure apparaissent fréquemment par moulage par injection lorsque des fronts séparés de polymère fondu se rencontrent. Elles induisent une réduction significative de la résistance à la rupture et de la déformation, en particulier pour les composites. Il est donc essentiel de prévoir de façon fiable leurs propriétés mécaniques pendant la phase de conception du produit, mais les outils de simulation actuels ne sont pas encore en mesure de le faire. La littérature met en évidence deux raisons principales : une diffusion macromoléculaire incomplète de la matrice polymère aux interfaces et un changement de la distribution d'orientation des fibres. Ce travail s’est donné pour objectif de caractériser et de quantifier la contribution de ces facteurs et de contribuer à améliorer la prédiction des propriétés mécaniques des polymères renforcés de fibres courtes moulés par injection.Des échantillons en PBT renforcé de fibres de verre à 30 % en poids ont été moulées avec des lignes de soudure frontale et fuyante. Les déformations dans les essais mécaniques ont été mesurées par corrélation d'images numériques pour quantifier la localisation dans les lignes de soudure. La microstructure a été déterminée par tomographie X. Nous avons pu notamment montrer que les lignes de soudure fuyantes ne s’estompaient que très lentement et que les fronts de matière se comportent vis-à-vis de l’autre comme des parois. Un modèle physique basé sur la théorie de la reptation a été mis en œuvre pour déterminer un critère de cicatrisation de l’interface. En utilisant la distribution d’orientation mesurée et un schéma d'homogénéisation adéquat pour chaque élément dans une simulation par éléments finis, les propriétés mécaniques jusqu’à la rupture du composite ont pu être calculés et expliquent la réduction des propriétés mécaniques au niveau des lignes de soudure, sachant que les interfaces étaient entièrement cicatrisées pour le matériau de l’étude. Enfin, pour cette matrice semi-cristalline, nous avons montré la nécessité d’utiliser une loi de comportement élastoplastique avec un seuil d’endommagement dépendant de l’orientation des fibres. / Weld Lines frequently appear by injection molding when separate polymer melt fronts meet. They induce a significant reduction in the failure strength and strain, especially for composites. It is therefore essential to predict reliably their mechanical properties during the product design phase, but current simulation tools are still not able to do it. Literature points to two main reasons of WL weakness: an incomplete polymer matrix healing and a change in the fiber orientation distribution. The objective of this work is to characterize and quantify the contribution of these factors and to contribute to improving the prediction of the mechanical properties of injection molded short-fiber reinforced polymers.Samples of 30 % wt. glass fiber-reinforced PBT were injection molded with frontal and flowing weld lines. The deformations in the mechanical tests were measured by of digital image correlation to quantify the location of deformation in the weld lines. The microstructure was quantified using X-ray computed tomography scans. In particular, we were able to show that the flowing weld lines were fading very slowly and that the material fronts behave towards each other like walls. A physical model based on reptation theory was implemented to determine a criterion for interface healing. Using the measured orientation distribution and an appropriate homogenization scheme for each element of a finite elements simulation, the mechanical properties up to the failure of the composite could be calculated and explain the reduction in mechanical properties at the weld lines, knowing that the interfaces were fully healed for the study material. Finally, for this semi-crystalline polymer, we have shown the need to use an elastoplastic constitutive law with a damage threshold depending on the orientation of the fibers.

Chacun s’accorde à reconnaître aujourd’hui que les activités humaines impactent significativement le climat de la planète. Le secteur de la construction est l’un des principaux responsables de cette situation car c’est le premier consommateur d’énergie et le deuxième émetteur de CO2 dans le monde. Il importe par conséquent de réaliser des bâtiments éco-respectueux, qui consomment peu d’énergie et émettent moins de gaz à effet de serre sur l’ensemble de leur cycle de vie. La présente étude s’intègre alors dans une problématique générale de développement de matériaux de construction innovants à impact environnemental réduit. Nous nous proposons ainsi d’utiliser la balle de riz comme granulat végétal dans une matrice cimentaire. L’objectif du travail est de proposer une méthode de formulation des bétons à bases de granulats végétaux et d’étudier le comportement mécanique et thermique du béton de balle de riz. Les essais de prise réalisés sur de la pâte de ciment pure formulée avec de l’eau issue de l’infusion de la balle de riz ont montré que ces granulats n’ont pas d’effet inhibiteur sur la prise du ciment. Pour confirmer cette hypothèse, une analyse chimique de la balle de riz a été réalisée et les résultats ont montré le taux d’extractibles des balles de riz est quasi nul contrairement à d’autres granulats végétaux tels que le chanvre et le bois. La méthode de formulation proposée consiste à déterminer la compacité du squelette végétal pour un mode de mise en œuvre déterminé, puis à formuler la pâte liante qui va occuper le volume poreux intergranulaire résiduel. La pâte est constituée du liant, de l’eau efficace, des additions et adjuvants éventuels, et de l’air piégé et/ou entrainé. Pour un volume d’air donné (et d’additions), les quantités de ciment et d’eau efficace sont alors ajustées pour atteindre les performances visées, sur la base de la loi de Féret. Cependant, pour ce type de béton, l’important volume d’air entrainé dépend (lui aussi) de la quantité de ciment et d’eau présents dans le mélange, de l’intensité du malaxage et du mode de coulage. Un modèle décrivant le volume d’air résiduel a été alors calibré à partir d’essais réalisés avec les constituants du béton que l’on souhaite fabriquer. Enfin le problème de la formulation est solutionné en recourant à un module d’optimisation numérique. Dans le but de valider le modèle, la méthode de formulation a été appliquée à cinq échantillons dont les résistances visées sont 0,5 ; 1 ; 2 ; 4 et 8 MPa. Les performances obtenues sont assez proches de celles visées. Par ailleurs il a été constaté que le mode de conservation des éprouvettes influe beaucoup sur les résistances mécaniques du matériau. En effet, une cure en condition dessiccation peut faire chuter les résistances mécaniques jusqu’à 60%. Les meilleures résistances obtenues ont été observées sur les éprouvettes conservées à 95 % de HR. Les mesures de la conductivité thermique ont montré que le béton de balle de riz constitue une très bonne alternative à des systèmes plus conventionnels en termes d’isolation thermique. La valeur moyenne de la conductivité thermique du béton de balle de riz varie en fonction du dosage en liant entre 0,070 W/(m.K) et 0,171 W/(m.K). L’évolution de la conductivité thermique en fonction de la masse volumique et du dosage en ciment est linéaire / Everyone agrees today that human activities significantly affect the climate of the planet. The construction sector is one of the main contributors to this situation as it is the largest energy consumer and the second largest CO2 emitter in the world. It is therefore important to build eco-friendly buildings, which consume little energy and emit less greenhouse gases throughout their life cycle. The present study is then integrated into a general problem of development of innovative building materials with reduced environmental impact. We propose to use the rice husk as a vegetable aggregate in a cementitious matrix. The objective of the work is to propose a method for the mix design of concretes based on plant aggregates and to study the mechanical and thermal behavior of rice husk concrete. Setting tests on pure cement paste formulated with water resulting from the infusion of the rice husk showed that these aggregates had no inhibiting effect on the setting of the cement. To confirm this hypothesis, a chemical analysis of the rice husk was carried out and the results showed that the extractable ratio of rice husks is almost zero, unlike other plant aggregates such as hemp and wood. The proposed formulation method consists in determining the packing density of the plant skeleton for a given method of implementation and then in proportioning the binder paste which will occupy the residual intergranular pore volume. The paste is consisted of the binder, the effective water, the possible additions and admixture, and trapped air and/or entrained air. For a given volume of air (and additions), the quantities of cement and effective water are then adjusted to achieve the targeted performances, based on the law of Féret. However, for this type of concrete, the large volume of entrained air also depends on the quantity of cement and water present in the mixture, the intensity of the mixing and the casting mode. A model describing the volume of residual air was then calibrated from tests carried out with the components of the concrete that it is desired to manufacture. Finally, the problem of formulation is solved by using a numerical optimization module. In order to validate the model, the method for the mix design was applied to five samples with a target resistance of 0.5; 1; 2; 4 and 8 MPa. The performances obtained are quite similar to those targeted. In addition, it has been observed that the preservation mode of the specimens has a significant influence on the mechanical strength of the material. Indeed, a cure in desiccation condition can reduce the mechanical resistances up to 60%. The best resistances obtained were observed on the specimens preserved at 95 % RH. Measurements of thermal conductivity have shown that rice husk concrete is a very good alternative to more conventional systems in terms of thermal insulation. The average value of the thermal conductivity of the rice husk concrete varies depending on the binder dosage between 0.070 W/(m.K) and 0.171 W/(m.K). The evolution of the thermal conductivity as a function of the density and the cement dosage is linear

Les assemblages acier-aluminium de tôles minces (0,8 à 2 mm) ont été beaucoup étudiés au début des années 2000 pour des applications automobiles, dans la perspective d'alléger les véhicules (projet européen Super Light Car). Dans ce contexte, le présent travail est réalisé en vue d'étudier les possibilités d'assemblage hétérogène acier-aluminium par la nouvelle variante du procédé de soudage MIG connue sous l'appellation CMT (Cold Metal Transfer). La première partie de l'étude est consacrée à la compréhension du principe de fonctionnement de ce procédé, en utilisant une plateforme équipée d'un système d'acquisition de données permettant les mesures synchronisées de tension, intensité, vitesse fil et d'images vidéo prises par une caméra rapide. Dans une seconde partie, nous présentons les caractéristiques métallurgiques des assemblages acier/aluminium réalisés en configuration à clin avec des jeux de paramètres couvrant toute la plage étudiée dans la partie précédente. On s'intéresse plus particulièrement à la zone créant la liaison entre l'acier et l'aluminium. Dans une troisième partie, la tenue mécanique des assemblages est évaluée par des essais de traction transverse quasi-statique et sous chargement cyclique. La résistance à rupture de la couche de réaction est aussi évaluée par une technique originale, habituellement dédiée à l'évaluation de l'adhérence des revêtements par choc laser. Enfin, nous proposons une nouvelle méthode pour estimer le rendement du procédé CMT basée sur la simulation numérique par éléments finis de l'évolution des champs de température lors du dépôt d'un cordon d'aluminium sur un substrat d'acier galvanisé, couplée à la modélisation de la croissance de la couche de réaction formée le long de l'interface acier/aluminium. / Joining of steel- aluminum thin sheets (0.8 to 2 mm) has been extensively studied in the beginning of 2000 years for automotive applications, in a regard to reduce vehicle weight (European Project Super Light Car). In this context, this work is carried out to study the possibilities of dissimilar steel-aluminum assembly by the new variant of the MIG welding process known as CMT (Cold Metal Transfer). The first part of the study is devoted to understand the operating principle of this process, using a platform equipped with a data acquisition system for synchronized measurements of voltage, current, speed wire feed and video images taken by a speed camera. In a second part, we present the metallurgical properties of steel-aluminum joints made in lap configuration with parameter sets covering the entire range studied in the previous section. We are especially interested in the area creating the connection between steel and aluminum. In the third part, the mechanical proprieties of connections are evaluated by quasi-static transverse tensile tests and under cyclic loading. The breaking strength of the reaction layer is also evaluated by an original technique, usually dedicated to the evaluation of the adhesion of coatings by laser shock. Finally, we propose a new method to estimate the efficiency of the CMT process based on the finite element numerical simulation of the evolution of temperature fields during the deposition of an aluminum weld on a galvanized steel substrate, coupled with modeling of the growth of the reaction layer formed along the steel / aluminum interface.

This work identifies alloy terminal freezing range, columnar growth, grain coarsening, liquid availability towards the terminal stage of solidification, and segregation towards boundaries as primary factors affecting the hot-cracking susceptibility of fusion-based additive manufacturing (F-BAM) processed alloys. Additionally, an integrated computational materials engineering (ICME)-based approach has been formulated to design novel Al alloys, and high entropy alloys for F-BAM processing. The ICME-based approach has led to heterogeneous nucleation-induced grain refinement, terminal eutectic solidification-enabled liquid availability, and segregation-induced coalescence of solidification boundaries during laser-powder bed fusion (L-PBF) processing. In addition to exhibiting a wide crack-free L-PBF processing window, the designed alloys exhibited microstructural heterogeneity and hierarchy (MHH), and thus could leverage the unique process dynamics of L-PBF to produce a fine-tunable MHH and mechanical behavior. Furthermore, alloy chemistry-based fine tuning of the stacking fault energy has led to transformative damage tolerant alloys. Such alloys can shield defects stemming from the stochastic powder bed in L-PBF, and consequently can prevent catastrophic failure despite the solidification defects. A modified materials systems approach that explicitly includes alloy chemistry as a means to modify the printability, properties and performance with F-BAM is also presented. Overall, this work is expected to facilitate application specific manufacture with F-BAM and eventually facilitate widespread adoption of F-BAM in structural application.

This paper examines how the initial austenite grain size in quench and partitioning (Q-P) processes influences the final mechanical properties of Q-P steels. Differences in austenite grain size distribution may result, for example, from uneven heating rates of semi-finished products prior to a forging process. In order to quantify this influence, a carefully defined heat treatment of a cylindrical specimen made of the Q-P-capable 42SiCr steel was performed in a dilatometer. Different austenite grain sizes were adjusted by a pre-treatment before the actual Q-P process. The resulting mechanical properties were determined using the upsetting test and the corresponding microstructures were analyzed by scanning electron microscopy (SEM). These investigations show that a larger austenite grain size prior to Q-P processing leads to a slightly lower strength as well as to a coarser martensitic microstructure in the Q-P-treated material.

Organic hybrid composites based on carboxylated nitrile rubber and nylon-12 reinforced with mercerized and diisocyanated lignocellulose residue (LCR) was prepared. The influence of the LCR on the viscoelastic properties of these organic hybrids was investigated by dynamic mechanical analysis and thermal analysis (differential scanning calorimetry (DSC)). It is found that either the position of the damping peak was shifted to higher values or the intensity of the damping peak was significantly increased with LCR. These results could imply that the LCR enhanced the damping properties of the composites. The thermal stability of the composites was evaluated with the mean values obtained using thermogravimetrical analysis. The decomposition rate was investigated using differential thermal gravimetry. The crystallization behavior of the prepared composites was checked by DSC.

L’objectif de ce travail est de caractériser le comportement mécanique de composites constitués à de matrices polymériques renforcées par des fibres naturelles. Les matériaux étudiés dans cette thèse sont le polypropylène pour la matrice et les fibres de coco pour les renforts. La caractérisation morphologique et mécanique de ces matériaux est entreprise grâce à l’usage de la microscopie électronique à balayage, la tomographie aux rayons X, la corrélation d’images numériques et la thermographie infrarouge. Dans une première partie, on a étudié en détail les fibres de coco dans trois états différents: à l’état naturel et après traitement chimique suivi ou non de séchage. Les fibres ont été observées en tomographie et leurs caractéristiques essentielles définies. Par ailleurs des essais mécaniques in-situ dans un microscope électronique à balayage ont été conduits pour l’obtention de leurs propriétés mécaniques. Il a quasi été procédé à la caractérisation mécanique du comportement de tissus de fibre en vue de leur utilisation dans un composite. Dans une seconde partie, le comportement mécanique du polypropylène (à l’état vierge ou recyclé) a été analysé grâce à des essais de traction à déplacement imposé et à diverses vitesses de chargement. Ces essais ont été instrumentés pour des mesures de champs de déplacement et de températures, les premiers servant à mesurer les états de déformation, la progression de l’endommagement et observer les modes de rupture du matériau. L’effet du recyclage est souligné et en particulier la dégradation des propriétés mécaniques. Les caractéristiques complètes (élasticité, pic et plateau et endommagement) et l’effet de la vitesse sur celles-ci sont exhibées pour les deux états. Dans la dernière partie du travail, on s’est intéressé au comportement du composite considérant la matrice à l’état vierge ou dans l’état recyclé. Les caractéristiques obtenues sont discutées en soulignant l’influence du mode d’élaboration utilisé et l’apport des fibres de coco. / The objective of this work is to characterize the mechanical behavior of composites made with recycled polymeric matrices reinforced with natural fibers. The materials studied in this thesis are the polypropylene matrix and the coconut fibers for reinforcement. The morphological and mechanical characterization of these materials is undertaken with the use of scanning electron microscopy, X-ray tomography, the digital image correlation and infrared thermography.In the first part, we studied in detail the coconut fibers in three different states: in its natural state and after chemical treatment followed or not drying. The fibers were observed in tomography and their essential characteristics defined. Furthermore in situ mechanical testing in a scanning electron microscope were conducted to obtain their mechanical properties. It has almost been carried out the mechanical characterization fabrics of the behavior for use in a composite. In a second part, the mechanical behavior of polypropylene (virgin or recycled state) was analyzed by tensile testing at imposed displacement and various charging speeds. These tests were instrumented for measurement of displacement fields and temperatures, the first to measure the deformation conditions, the progression of the damage and observe the failure modes of the material. The effect of recycling is particularly pointed out and degradation of mechanical properties. Complete specifications (elasticity, peak and shelf and damage) and the effect of speed on them are exhibited for both states. In the last part of the work, it was interested in the behavior of the composite matrix considering the blank state or in the recycled state. The characteristics obtained are discussed emphasizing the influence of the method of production used and the contribution of coconut fibers.

Ce travail de thèse s’est attaché à investiguer, d’une part, le mécanisme d’érosion interne par suffusion dans les ouvrages hydrauliques en terre, et d’autre part, les conséquences qu’il pourrait avoir sur le comportement mécanique du sol, l’objectif principal étant d’améliorer notre compréhension de ce processus et du comportement des sols érodés. La démarche adoptée est principalement expérimentale, réalisée à différentes échelles : du macroscopique, à l’échelle du matériau, au microscopique, à l’échelle des grains constitutifs. A l’échelle macroscopique, des essais de suffusion ont été réalisés sur des échantillons de sol à l’aide d’un nouveau dispositif d’essai d’érosion, appelé perméamètre de suffusion, développé dans le cadre de cette thèse. Après érosion dans le perméamètre, les échantillons érodés sont transférés par une procédure de congélation / décongélation dans un dispositif d’essai triaxial afin d’étudier leur comportement sous chargement mécanique. Les résultats obtenus à cette échelle ont permis de donner un aperçu général du mécanisme de suffusion et de mettre en évidence son impact sur les propriétés de résistance au cisaillement du sol. A l’échelle microscopique, une analyse fine a pu être menée en réalisant un essai de suffusion des mesures in-operando de tomographie à rayons X et de la visualisation locale par techniques optiques sur un sol artificiel. La caractérisation du sol à cette échelle microstructurale a permis de mieux comprendre le processus de suffusion, notamment en mettant en évidence l’apparition et le développement de fortes hétérogénéités qui semblent avoir une influence importante sur la réponse mécanique des sols érodés / This thesis work has investigated, on the one hand, the mechanism of internal erosion by suffusion in earthen hydraulic structures, and, on the other hand, the consequences suffusion can cause on the mechanical behavior of soils, the main objective being to improve our understanding of both the suffusion process and the behavior of eroded soils. The approach adopted was mainly experimental, by a multi-scale scope: from macroscopic, at the material scale, to microscopic, at the grain scale. At the macroscopic scale, suffusion experiments were performed on gap-graded cohesionless soil samples using a newly developed testing device, called the suffusion permeameter. Then, the eroded samples are transferred by a freeze/thaw procedure to a triaxial device to study their behavior under mechanical loading. The achieved results provide a general overview of the suffusion mechanism at the sample scale and highlight its impact on soil shear resistance properties. At the microscopic scale, the suffusion mechanism has been studied by performing a suffusion test with in-operando x-ray tomography and using local visualization based on optical techniques in an artificial soil. Subsequent grain-scale analysis has provided a deeper understanding of suffusion process through the characterization of the eroded soil microstructure, particularly highlighting the occurrence and development of strong heterogeneities, which appear to play a key role in the macroscopic mechanical behavior of eroded soils

[pt] Neste trabalho foi realizado um estudo comparativo do desempenho mecânico e da durabilidade de concretos reforçados com macrofibras discretas de sisal e polipropileno. Foram utilizadas duas matrizes cimentícias com teores distintos de material pozolânico. As duas fibras, com comprimento de 51 mm, foram incorporadas em dosagens de 3 a 15 kg/m3. Foram realizados ensaios de tração direta para ambas as fibras, obtendo-se valores de tensões equivalentes. Para caracterização mecânica dos compósitos, foram realizados ensaios de flexão em três pontos sob carregamento monotônico, de acordo com o procedimento da norma EN 14651. Também se avaliou este comportamento sob carregamentos cíclicos. Na avaliação da aderência fibra-matriz, ensaios de arrancamento foram realizados. A fibra de sisal apresentou menor aderência nas duas matrizes. Todos os compósitos com fibras de sisal e polipropileno apresentaram comportamento deflection softening quando submetidos à flexão. Para se obter desempenho mecânico na flexão similar para ambas as fibras, foi necessário aproximadamente o dobro da dosagem de fibras de sisal. De acordo com a classificação proposta pelo fib Model Code, essas fibras podem substituir parcialmente ou integralmente o reforço convencional no estado limite último. A durabilidade dos compósitos foi estudada por meio de processo de envelhecimento acelerado, utilizando-se ciclos de molhagem e secagem. A utilização do reforço de sisal na matriz com maior alcalinidade apresentou degradação, enquanto que sua incorporação na matriz livre de hidróxido de cálcio não resultou em perdas mecânicas após os ciclos. Concretos reforçados com fibras de polipropileno não apresentaram degradação pelos processos de envelhecimento acelerado. / [en] This work aims to present a comparative study of the mechanical performance and durability of concretes reinforced with discrete sisal and polypropylene macrofibers. Two cementitious matrices with different pozzolan material content were used. The both fibers were incorporated into fractions of 3 to 15 kg/m3 and were 51 mm long. Direct tensile tests were performed for the fibers, achieving equivalent stress values. For mechanical characterization of the composites, three-point flexural tests were performed under monotonic loading in accordance with the EN 14651 procedure. The behavior under cyclic loading was also investigated. To evaluate the fiber-matrix interaction, pull out tests were performed. The sisal fiber showed lower adhesion with the two matrices. All the composites with sisal and polypropylene fibers presented deflection softening behavior when subjected to flexural loads. In order to obtain similar flexural mechanical performance for both fibers, approximately twice dosage of sisal fiber was required. According to the classification proposed by fib Model Code, these fibers can partially or fully replace the conventional reinforcement at ultimate limit state. The durability of the composites was studied by accelerated aging process through wetting and drying cycles. The use of sisal fibers as reinforcement in the matrix with higher alkalinity showed degradation, while its incorporation into the matrix free of calcium hydroxide did not result in mechanical losses after the cycles. Concretes reinforced with polypropylene fibers did not present degradation caused by accelerated aging processes.

[pt] O baixo custo, aliado a redução de peso e consequente aumento da eficiência, atingindo os mesmos níveis desejáveis de resistência mecânica, tem seduzido diversos setores da indústria à extensão do uso de polímeros termoplásticos em seus produtos finais. Dentro desses setores, o aumento em volume do emprego de polímeros não só tem crescido em aplicações de uso gerais, como também em aplicações estruturais. Com isso, o conhecimento detalhado do comportamento mecânico desses materiais faz-se necessário a fim de assegurar suas devidas propriedades em trabalho, sendo atrativo o uso de modelos constitutivos para a predição do comportamento final. Entretanto, os polímeros são materiais semicristalinos que possuem mecanismos de deformação e falha complexos. A maioria dos polímeros deformam-se homogeneamente até o escoamento, porém após esse, devido a estricção, o campo de deformações torna-se heterogêneo, fazendo com que o uso de técnicas experimentais clássicas, como a extensometria, seja inadequado. Dentre os métodos mais apropriados para a avaliação de polímeros em altas deformações, pode-se destacar a correlação de imagens digitais (CID). A técnica CID permite a avaliação da variação local da deformação e é capaz de prover uma descrição completa da deformação, inclusive na região do pescoço. Apesar do potencial de uso da CID em polímeros, seu emprego ainda é incipiente devido ao desenvolvimento recente da técnica. Dessa forma, o presente trabalho tem como objetivo a avaliação do comportamento de polímeros termoplásticos sob grandes deformações mediante o uso da técnica CID. Diante do alto custo dos sistemas CID comerciais, desenvolveu-se um arranjo e procedimento simples para a aquisição e análise das imagens digitais. A fim de predizer o comportamento mecânico e entender melhor os mecanismos de deformação envolvidos, diversos modelos constitutivos também foram testados. / [en] Low cost, coupled with weight reduction and consequent increase in efficiency, reaching the same desirables levels of mechanical strength, has seduced several industry sectors to expand the use of thermoplastic polymers in their final products. Within these sectors, the increase in volume of polymer has not only grown in general use, but also in structural applications. Thus, in order to ensure their proper properties in work, the detailed knowledge of the mechanical behavior of these materials is necessary and the use of constitutive models for the prediction of the final mechanical behavior becomes attractive. However, polymers are semi-crystalline materials that show complex deformation and failure mechanisms. Most of the polymers deform homogeneously until the yield point, but after, due to necking, the strain field becomes heterogeneous, making the use of classic experimental techniques, such as extensometry, inadequate. Among the most appropriate methods for the evaluation of polymers at large deformation, it is possible to highlight the digital image correlation (DIC). DIC technique allows the evaluation of local strain and is able to provide a complete description of the strain field, including the neck region. Despite the potential of DIC in polymers, its use is still incipient due to the recent development of the technique. Thus, the present work has the objective of evaluating the behavior of thermoplastic polymers under large deformation using DIC. Given the high cost of commercial DIC systems, a simple arrangement and procedure for the acquisition and analysis of the digital images was developed. In order to predict the mechanical behavior and to better understand the mechanisms of deformation involved, several constitutive models were also tested.