Full Paper wileyonlinelibrary.com 907 Macromolecular Materials and Engineering © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim DOI: 10.1002/mame.201500463 1. Introduction Anisotropy of mechanical properties is the basic trait of short glass fiber reinforced polymers (SFRPs) shaped by the injection molding process. The degree of anisotropy depends on microstructure heterogeneities, which result from fiber orientation and density distributions. Accurate evaluation of mechanical performance and durability of structural moldings requires consideration of process- induced anisotropy and the possible existence of micro- metric porosity. In this context, integrative simulation chains (ISC) are developed to integrate forming process Large-scale X-ray microcomputed tomography (μ-CT) is used to investigate microstructural features of weld lines in a short glass fiber reinforced polymer. The main originality of this work is related to the evaluation of local structural and mechanical characteristics in zones of unmastered heterogeneities. Complete and incomplete injection molded plates are con- sidered to investigate weld lines with and without process-induced porosity. Using a helical scanning trajectory, the full 3D microstructure is obtained at centimetric scale to cover a large zone including first contact between colliding fronts at a voxel size of 3 μm. Microstructure analyses show that weld line area is ill-ordered at the fiber and structure length scales. Near the first contact point, fiber orienta- tions show the signature of vortexes, which mark the presence of repulsive forces. The presence of micrometric porosity is only con- firmed in incomplete plates. μ-CT images are used as inputs to create a full-scale finite element model for assessing strain locali- zation. Predicted principal strains are compared to digital image correlation measurements performed during uniaxial tensile tests. Full-scale modeling combined to 3D high-resolution imaging proves high potential to correlate local fiber heterogeneities with strain localization effects. Large-Scale X-Ray Microtomography Analysis of Fiber Orientation in Weld Line of Short Glass Fiber Reinforced Thermoplastic and Related Elasticity Behavior Abderrahmane Ayadi, Hedi Nouri, Sofiane Guessasma,* Frederic Roger A. Ayadi, Dr. H. Nouri, Prof. F. Roger Department of Polymers and Composites Technology & Mechanical Engineering Mines Douai, 941 rue Charles Bourseul, CS 10838, 59508, Douai, France Dr. H. Nouri Ecole Nationale d’Ingénieurs de Sfax Laboratoires des Systèmes Electromécaniques Route Soukra Km 3, BPW 3038, Sfax, Tunisia Dr. S. Guessasma INRA, Research Unit BIA UR1268 Rue Geraudiere F-44316, Nantes, France E-mail: sofiane.guessasma@nantes.inra.fr Macromol. Mater. Eng. 2016, 301, 907−921