Most of the norms used in the field of digital image (and volume) correlation to registertwo images (or volumes) lead to ill-posed problems. One of the frequent solutions is toenforce a restricted kinematics requiring a compromise between the richness of thesolution (i.e., the spatial resolution) and the measurement uncertainty. An alternativeroute is to use a displacement norm that permits to alleviate this compromise by the meansof a mechanical regularization used when the gray levels do not give enough information.It is then possible to compute a displacement vector for each pixel orvoxel, inducing lower residuals (in terms of experimental data) whiledecreasing the noise sensitivity. The resolution performance of these different approachesis discussed, and compared for the analysis of a tensile test on a cast iron specimenbased on a pair of tomographic images. As representative reconstructed volumes lead to alarge number of degrees of freedom, a dedicated GPU computational strategy has beendeveloped and implemented.

Osteoporosis is a disease characterized by a loss of bone density and an altered bonearchitecture. These modifications lead to an increased risk factor for bone fracture,particularly of the femoral neck. This disease can be explained by a disorder in the boneremodeling process which is triggered by the apparition of micro-cracks within the bone.According to Frost’s theory [1], these micro-cracksappear for a specific local strain threshold. Thus, the knowledge of the microarchitectureand quality of trabecular bone is essential to determine this local strain threshold. Thispaper studied the mechanical trabecular bone behavior of 43 patients diagnosed asosteoporotic whose femoral heads were replaced by hip prosthesis. From each patient, acylinder-shaped of trabecular bone samples was cored. Each sample was scanned by X-raymicro-tomography before a compression test in order to reconstruct a reliableFinite-Element (FE) model of the bone architecture in Abaqus. The force-displacementcurves were recorded for all the samples and calibrated by the experimental responses. Theforce-displacement numerical curves were adjusted to the experimental ones, by modifyingthe tissue microscopic mechanical behavior. This process leads to the determination of thelocal strain threshold responsible for triggering the bone remodeling process.

Evaluation of the dynamic properties of quasi-brittle materials is of the utmostimportance for assessing the vulnerability of structural components under dynamic loadingssuch as collision or explosion. To investigate the dynamic strength of (quasi)-brittlematerial, three-point bending tests are performed on a modified Split Hopkinson PressureBar. Such an apparatus is often used with pre-cracked specimen to determine the dynamicstress intensity factor of metallic materials. With quasi-brittle materials special carehas to be paid to the processing of the test since fracture can occur at very low strains.The specimen remains in an out-of equilibrium state and fracture occurs before the supportreactions appear as if it was a support-free impact test. A special non-equilibriumanalytical approach has been developed to process the tests. Finite-element simulationsare used to assess relevance of the proposed analysis for normalized short beams.Experimental results on brick and concrete samples showing a significant dynamic strengthincrease are presented.

This paper is based on additional treatments of the experimental results obtained by L. Bodelot, L. Sabatier, E. Charkaluk, P. Dufrénoy [Experimental setup for fully coupled kinematic and thermal measurements at the microstructure scale of an AISI 316l steel, Mater. Sci. Eng. A 501 (2009) 52–60]. In order to perform inter- and intragranular thermomechanical analyses in a metallic polycrystal at the grain scale, a crystallography-based projection technique of the thermal and displacement fields on a polynomial basis is proposed. It enables intragranular coupled analysis of strain and temperature full-field data consistent with the plastic slip activation observed on specimen surface after the test.

In this paper, an analytical approach is proposed to model chip formation in the case ofturning process. Numerical simulations of chip genesis are performed in order to fitefficiently the proposed analy- tical model. In particular, cutting edge radius influence,temperature and internal stresses distribution are studied using finite element modelling.Numerical model setting is made with experimental and literature data using forces andchip thickness.

Stirred bead mills used in industry allow to split up particules in suspension byagitating a milling medium. The multiple impacts may damage beads and thus reduce thestirred milling process efficiency. A discrete numerical approach including simple fluideffects is proposed and carried out in this paper to model and study finely the damagephenomenon. The simulation data allow to identify internal variables of the milling mediumand to localize high energy zones. The order of magnitude of contact forces includingfluid contribution will enhance the bead wear law.

Since 1994, HDS is a major player in the design of complex composite parts, especiallyfor racing sailing yachts [1]. In this paper, wesuggest to present our approach in the design and finite-element modelling of the rigidwing-sail of the trimaran that won the 33rd America’s Cup, held in February 2010. From thedecision to design the wing-sail to the assembly on the maxi trimaran, we will present thedifferent steps of design and computation: principles and assessment of the aerodynamicloads, structural design and modelling with tools adapted to each problem, massoptimization. Then, we will detail some of the numerical problems that we faced in thisproject.