Aseptic loosening due to wear-induced osteolysis remains a leading cause of failure in total hip arthroplasty (THA), particularly in revision cases beyond the second decade of use. Historically, there have been large amounts of variability of wear within individual THA patient cohorts. Evidence indicates that femoral head damage can be a cause of this variability. While femoral head damage as a result of third body particles and subluxation and dislocation events has been well documented, direct quantifiable linkage between femoral head damage and wear acceleration remains to be established. Due to large ranges of observed retrieval damage, wear testing protocols for simulating third body and other damage effects have been subject to a wide range of variability, making it difficult to know where the clinical reality lies. To study the effect of retrieval femoral head damage on total hip implant wear, a damage-feature-based finite element (FE) formulation which allowed for wear prediction due to individual damage features developed. A multi-scale imaging procedure was also developed to globally map and quantify micron-level damage features appearing on retrieval femoral heads. This allowed for wear simulations of damage patterns observed on specific retrieval femoral heads. Retrieval damage was shown to be highly variable among patients, and capable of producing up to order-of-magnitude wear increases when compared to undamaged head wear rates. Damage following dislocation and subsequent closed reduction maneuvers was particularly detrimental, with average wear rate increases equal to half an order of magnitude. These data were used to develop wear testing protocols for simulating clinically-occurring third body and other damage effects.

Les structures composites sont de plus en plus présentes dans le domaine aéronautique. Le perçage, procédé qui permet le montage de fixations pour assembler ces structures, peut induire des défauts tels que délaminages, écaillages, arrachements de fibres ou surchauffes au niveau de l’alésage.Dans la littérature les auteurs s’intéressent principalement aux défauts créés en entrée et en sortie de trou. Aussi, cette recherche s’est focalisée sur les défauts de paroi crées par l’opération de perçage. Une caractérisation qualitative et quantitative a été proposée et le lien entre ces défauts et la tenue mécanique a été évalué.L’état de surface des parois est quantifié via sa rugosité qui mesure globalement les défauts générés lors du perçage. Jusqu’à présent, la qualité de la surface est estimée par un critère de rugosité géométrique Ra issu de la culture métallique. Il présente un certain nombre d’incohérences pour les perçages des composites. Dans ce travail de thèse, les relations entre les paramètres de perçage, le matériau de l’outil, sa géométrie et la qualité des alésages mesurée par les critères normalisés d’état de surface ont été établies. Un critère de qualité des parois de trou pour les matériaux composites autre que les critères normalisés a été proposé.La nature intime de la surface de contact influence clairement la qualité du transfert de charge par contact localisé. Dans un premier temps, l’influence des défauts de paroi sur la tenue en matage quasi-statique a été établie, ensuite, la tenue en compression quasi-statique des stratifiés C/E liée à la présence de défauts de paroi a été étudiée. Une analyse de la tenue en fatigue des stratifiés percés liée à la présence des défauts d’état de surface a aussi été réalisée. Enfin, une analyse numérique originale par éléments finis incluant une représentation géométrique des défauts observés, a permis de mieux cerner la cinétique d’endommagement des stratifiés percés liés à la présence de défauts de paroi / Composite materials are finding an increasing number of applications in the aerospace industry. The drilling is the process that allows the fasteners installation. The drilling operation can induce defects such as delamination, fibers and matrix pull-out and matrix burning.Previous studies focused mainly on the defects created at the hole entry and exit. Only few of these studies concern the hole wall drilling defects. In this study, we focused on the hole wall defects created by the drilling operation. A qualitative and quantitative characterization of defects was proposed and the relationship between these defects and the mechanical strength was evaluated.The hole surface finish is quantified by the roughness criterion Ra, that comes from metallic culture. Because of their heterogeneous nature, composite materials do not present the same defects patterns as metallic materials. The question that arises is whether the roughness may have an influence on the mechanical behavior of composite materials. In this study, the relation between the drilling parameters, the drill material, its geometry and the hole quality quantified with normalized parameters has been established. A criterion used to quantify the hole surface finish of composites have been proposed.The inner nature of the contact surface clearly influences the load transfer quality. As a first step, the influence of the hole wall defects on the quasi-static bearing behavior has been established, then the compressive behavior linked to the presence of hole wall defects have been studied. An analysis of the fatigue behavior of drilled laminates due to the presence of hole wall defects have been conducted.Finally, a numerical analysis by finite elements including an original geometric representation of the defects observed, has allowed to further clarify the damage kinetics of drilled laminates linked to the presence of drilling defects.

<p>  </p> <p>The development of the semiconductor industry is encountering a giant leap recently as Moorse’s is extended to the next levels. Advanced nanomanufacturing technology is the major challenge in the way. Higher resolution down to a few nanometers as well as higher throughput is always the key. As the optical lithography determines the feature size, the photomask is still in need of a low-cost and high resolution maskless patterning tool. In another aspect, the growing information allows the generation and storage of data at ever faster rates, which has led to the era of big data reaching a heroic amount of 7 zettabytes of total data in 2020. Future growth requires the total shipment of data storage capacity to double roughly every two years or less. For the future generation of magnetic data storage, the bit patterned medium (BPM) in combination with the current heat assisted magnetic recording (HAMR) is expected to increase the areal storage capacity by another order of magnitude by physically isolating magnetic bits at the nanoscale. Electron beam lithography (EBL) as a universal maskless lithography technique shows great resolution but has a high tool cost and low process throughput. Scanning probe lithography (SPL) is another family of nanoscale patterning techniques with low tool cost but the practical throughput is still limited. For example, dip pen nanolithography utilizes an AFM probe as a writing pen in direct patterning, but the ink delivery is limited by the rate of ink’s capillary transport. Other SPLs such as thermal probes with capabilities of 3D fabrication and surface oxidation via chemical reactions are all facing similar limitations in throughput. One way of breaking this limitation is to use parallel writing with millions of probes which also faces uniformity problems. </p> <p>In this Ph.D. dissertation, we report our Surfing Scanning Probe lithography (SSPL) method which can boost the scanning speed of SPL by several orders of magnitudes at a low cost by using a hydro-aero-dynamic scanning scheme. We use a homemade patterning head to continuously scan over a partially-wet spinning substrate at a linear speed of meters per second. The head carries several metallic tips which emit electrons and induce electrochemical reactions inside a gap of 10 nm scale. We use a liquid phase precursor and deliver it using the near-field electrospinning method and microfluid structures during the fast patterning. The best linewidth demonstrated is about 15 nm in full-width half maximum (FWHM) which can be further improved using smaller scanning gaps and sharp probe tips. Besides direct writing with a liquid precursor, SSPL can work with gas precursors as well enabled by nano plasma. The rate of material deposition is much high than conventional SPL. The SSPL system is a low-cost nanopatterning technology to produce patterns at high throughput and high resolution.</p>