HAL Portal UTC Université de Technologie de Compiègne
Not a member yet
11652 research outputs found
Sort by
Context-Aware Sustainable Design: Knowledge Graph-Based Methodology for Proactive Circular Disassembly of Smart Products
No full textInternational audienceIn nowaday's industrial landscape, the reduction of greenhousegas emissions has become imperative, requiring a profound revisionof product design practices to reduce their environmental impactthroughout their life cycle. Design for X (DfX) approaches, inparticular Design for Disassembly (DfD) and Design for Circularity(DfC), offer promising solutions by integrating environmentalindicators from the earliest stages of the design process. This articleproposes a methodological framework aimed to create sustainablesmart products. The framework takes advantage of CircularDisassembly indicators disseminated proactively and contextuallywithin the Product Lifecycle Management (PLM), and theManufacturing Process Management (MPM). Delving deeper intoDesign for Circular Disassembly (DfCD) approach, and the growingrole of artificial intelligence by using a knowledge graph. Byseamlessly integrating proactive environmental design indicatorsright from the preliminary phases of PLM, and MPM systems, theproposed framework promotes the development of a sustainablesmart products, helping to reduce design errors and time-to-market.This innovative approach underlines the central role of early designdecisions in promoting environmental sustainability within industry
Influence of the initial pressure and temperature on the explosion behavior of methane and hydrogen in pipings
No full textInternational audienceIn nowaday's industrial landscape, the reduction of greenhousegas emissions has become imperative, requiring a profound revisionof product design practices to reduce their environmental impactthroughout their life cycle. Design for X (DfX) approaches, inparticular Design for Disassembly (DfD) and Design for Circularity(DfC), offer promising solutions by integrating environmentalindicators from the earliest stages of the design process. This articleproposes a methodological framework aimed to create sustainablesmart products. The framework takes advantage of CircularDisassembly indicators disseminated proactively and contextuallywithin the Product Lifecycle Management (PLM), and theManufacturing Process Management (MPM). Delving deeper intoDesign for Circular Disassembly (DfCD) approach, and the growingrole of artificial intelligence by using a knowledge graph. Byseamlessly integrating proactive environmental design indicatorsright from the preliminary phases of PLM, and MPM systems, theproposed framework promotes the development of a sustainablesmart products, helping to reduce design errors and time-to-market.This innovative approach underlines the central role of early designdecisions in promoting environmental sustainability within industry
Experimental characterization of piezoelectric and elastic operational field-dependent non-linearities of multilayer benders for resonant driving of bone-conduction hearing aids via a dual-actuators side-by-side device
No full textInternational audienceA soft piezoceramic multilayer (ML) bending thin and thick dual-actuators side-by-side device, for use in bone-conduction hearing aids (BCHA), was characterized experimentally. For this purpose, first, quasi-static (0.1 Hz square wave) transverse displacements (deflections) of each ML bender were measured using a laser vibrometer (LV) under unimorph and bimorph drivings at various non-amplified peak (p) voltages (1Vp–13Vp). The resulting peak displacement–voltage curves were found clearlynonlinear, indicating a pronounced piezoelectric (PE) field-dependent nonlinearity (FDNL). Then, experimental electric impedance analyses were conducted for each ML bender, using an impedance analyzer, under 1Vp unimorph driving for the whole audio frequency range (20Hz–20 kHz). The identified three modes’ superposed impedance magnitudes and phases showed their increasing deviation to the frequency scale left with increasing the modes’ order, indicating a possible softening elastic FDNL, as confirmed later by harmonic frequency response LV measurements at 1Vp. Finally, the harmonic frequency responses, for the above audio frequency range, were measured for each ML bender using the LV under unimorph and bimorph drivings at various non-amplified voltages (1Vp–10Vp). Here,beside the PE FDNL, the frequency response functions showed clearly a pronounced softening elastic FDNL. Consequently, with increasing input voltages, the identified two modes’ displacement amplitudes were nonlinearly increasing, while resonant frequencies and corresponding quality factors were nonlinearly decreasing. The three parameters-voltage curves were found to fit well (R2 ~ 1) with highorder polynomials. These experimental results contradict the widely assumed displacement–potential linearity of middle ear or BCHA implantable PE vibrators of open literature available types (with orwithout shim bimorphs, unimorphs or diaphragms, and stacks) under similar targeted driving voltage and frequency ranges. The ML benders type quasi-static, frequency response and electric impedance characterizations, as well as the dual actuators side-by-side device, are proposed here for the first time for hearing aid applications
Effects of grain size and β fraction on the deformation modes of a Ti-6Al-2Sn-4Zr-2Mo-Si alloy with equiaxed (α + β) microstructures: Slip trace analysis and multiscale simulation of polycrystal plasticity
No full textInternational audienceThis study investigates the mechanisms behind the great mechanical properties observed at room temperature for a dual-phase Ti-6Al-2Sn-4Zr-2Mo-Si titanium alloy with equiaxed (α + β) microstructures. More precisely, analyzing the material deformation modes and the possible effects of β fraction and grain size was done to better understand such micromechanisms. With this idea in mind, uniaxial tensile deformation tests were performed at room temperature, and the resulting mechanical behaviors were analyzed. It was observed that increasing β fraction would enhance the overall ductility and work hardening while conversely decreasing the material resistance. Additionally, the material strengthening due to grain size effect, quantified by the Hall-Petch parameter, was also found to be dependent on β fraction. Slip trace analysis was conducted to understand the effects of grain size and β fraction on the activation of the basal , prismatic , and pyramidal slip systems and their critical resolved shear stress (CRSS) ratios were established. The qualitative study of CRSS ratios revealed that at smaller grain sizes, the basal slip systems were dominant (e.g. basal/prismatic CRSS ratio of 0.86 for d=2.98 µm) whereas the prismatic slip systems were prevalent and more easily activated for coarser grains (e.g. basal/prismatic CRSS ratio of 1.19 for d=4.21 µm). Such CRSS ratios were then used to identify the material parameters of a self-consistent multiscale model employed to reproduce the tensile behaviors. For a more quantitative analysis, the CRSS values were evaluated and correlated to grain sizes with Hall-Petch relations. Clear correlations regarding grain size and β fraction were found for the CRSS of prismatic and pyramidal systems. However, special attention was given to the ambiguous results regarding basal slip systems because of the potential manifestation of the compatibility stresses and grain boundary sliding mechanisms due to the higher density of grain boundaries at small grain sizes
Towards a data-driven paradigm for characterizing plastic anisotropy using principal components analysis and manifold learning
No full textInternational audienceIt is understood that anisotropic plastic behavior is strongly affected by the initial crystallographic texture and subsequent evolutions in the same during any kind of mechanical deformation. This means that macroscopic phenomenological modeling is inadequate since it leaves out any and all data related to texture, such as pole figures. While this shortcoming has long provided an argument for necessarily including micro-mechanical models (using crystal plasticity theory), the reality is that such simulations are time consuming and computationally expensive. In this paper, we present some developments that could be used in a novel model-free data-driven method for linking mechanical behavior directly with crystallographic texture, using manifold learning. Illustrated using numerically build data, our paradigm detects the intrinsic dimensionality of crystallographic texture data and represents it in feature space, as a function of micro-mechanical parameters. This would eventually enable local learning and interpolation to facilitate data-driven simulations
Security-Bag : Un Système de Détection d'Intrusion basé sur les spécifications appliqué aux réseaux BLE à topologie en étoile
No full textInternational audienceBluetooth Low Energy (BLE), a protocol widely used in IoT applications, enables efficient data exchange with low-cost, resource-constrained devices. Unfortunately, BLE's numerous vulnerabilities and poor vendor patching policies, combined with the lack of seamless update mechanisms for BLE devices, expose these systems to various wireless attacks, jeopardizing the safety and security of IoT applications. This underscores the need for an Intrusion Detection System (IDS). However, IPbased IDS systems have limited BLE attack detection scope, and existing BLE-specific IDS solutions, particularly those using unreliable, Received Signal Strength Indication (RSSI)-dependent sniffers/probes and static thresholds in attack detection, suffer from limitations due to the dynamic aspects of BLE devices, such as device mobility and connection parameters update, in their designs. In this paper, we propose the Security Bag component: a specification-based IDS applied to star topology BLE networks that implements security rules derived from the BLE specifications. We validate this Security Bag by simulating spoofing attacks on a BLE sensor node using the Contiki Cooja simulator. The obtained results show that the Security Bag promptly detects the injected attack, opening avenues for applications on other wireless networks and deployment in real systems.Bluetooth Low Energy (BLE), un protocole largement utilisé dans les applications IoT, permet l'échange efficace de données avec des dispositifs à faible coût et à ressources limitées. Malheureusement, les nombreuses vulnérabilités de BLE et les mauvaises politiques de correction des fournisseurs, combinées à l'absence de mécanismes de mise à jour transparents pour les dispositifs BLE, exposent ces systèmes à diverses attaques sans fil, mettant en péril la sûreté et la sécurité des applications de l'IoT. Cela souligne la nécessité d'un système de détection d'intrusion (IDS). Cependant, les systèmes IDS basés sur IP ont une portée limitée dans la détection des attaques BLE, et les solutions IDS existantes spécifiques au BLE, en particulier celles qui utilisent des renifleurs/sondes peu fiables, dépendant de l'indication de la force du signal reçu (RSSI) et des seuils statiques dans la détection des attaques, souffrent de limitations à cause des aspects dynamiques des dispositifs BLE, tels que la mobilité des dispositifs et la mise à jour des paramètres de connexion, dans leurs conceptions. Dans cet article, nous proposons le composant Security Bag : un IDS basé sur les spécifications appliqué aux réseaux BLE à topologie en étoile qui met en œuvre des règles de sécurité dérivées des spécifications BLE. Nous validons ce Security Bag en simulant des attaques Spoofing sur un nœud de capteur BLE à l'aide du simulateur Contiki Cooja. Les résultats obtenus montrent que le Security Bag détecte rapidement l'attaque injectée, ce qui ouvre la perspective d'applications sur d'autres réseaux sans fil et d'un déploiement dans des systèmes réels
Computational Shape Derivatives in Heat Conduction: An Optimization Approach for Enhanced Thermal Performance
No full textWe analyze an optimization problem of the conductivity in a composite material arising in a heat conduction energy storage problem. The model is described by the heat equation that specifies the heat exchange between two types of materials with different conductive properties with Dirichlet-Neumann boundary conditions on the external part of the domain, and on the interface characterized by the resisting coefficient between the highly conductive material and the less conductive material. The main purpose of the paper is to compute a shape gradient of an optimization functional in order to accurately determine the optimal location of the conductive material using a classical shape optimization strategy. We also present some numerical experiments to illustrate the efficiency of the proposed method
A membrane finite element for fast simulation of overlapping beads geometry during direct energy deposition additive manufacturing
No full textInternational audienceThe aim of this paper is to propose a fast FEM strategy for simulating molten metal deposition geometry during additive manufacturing for studying the influence of the sequence of deposition on the geometry. The approach is inspired by the algorithm initially proposed by Feulvarch et al. [Eur. J. of Mech. / A 89 ( 2021) 104290] for coatings. In this article, the membrane finite element is notably improved and extended for simulating of a large stack of deposits in order to study the building of 3D geometries. A constant vertical evolution rate of the surface tension is introduced to adjust the geometry of the free surface of the molten pool which depends on the hydrodynamics of the liquid phase. The simulation is very fast because it is carried out on a 2D mesh composed of linear triangles that corresponds to the sole free surface of the liquid phase at each time step. Moreover, the implicit nonlinear algorithm developed has the advantage of avoiding matrix systems resolution (reduced RAM memory, efficient parallel computing). In addition, a simple and robust remeshing procedure is detailed in order to avoid too large distortions of the triangular elements during the ’inflating’ stage of the workpiece. Its interest lies in the fact that it does not require any field projection typically employed in remeshing procedures, as the geometry serves as the only historical data required to resume FEM computations following each remeshing step. Examples are proposed to clearly evidence the efficiency and robustness of the method developed in terms of geometry and CPU time
Blocked-flow vs. free-flow cyanoacrylate glue embolization: Histological differences in an in vivo rabbit renal artery model
No full textInternational audiencePurpose: The purpose of this in vivo animal study was to compare the acute histological effects on the arterial vessel wall of free-flow vs. blocked-flow embolization with metacryloxysulfolane-n-butyl cyanoacrylate (MS-NBCA) in several concentrations. Materials and methods: A total of 42 rabbit renal arteries were embolized using MS-NBCA mixed with ethiodized oil. The MS-NBCA concentration was 12.5%, 25%, or 50%. All mixtures were injected under both freeflow and blocked-flow conditions. The rabbits were euthanised 30 min after arterial embolization. Arteriallumen distension, intimal inflammation and necrosis, peri-arterial edema, and distality of MS-NBCA penetration were assessed histologically. Multivariable regression analyses were performed using a manual backward procedure, with linear, ordinal and logistic regression to search for factors associated with these outcomes Results: Marked or severe dilatation was observed in 36 out of 42 arteries (86%) and marked or transmural intimal arteritis in all 42 arteries (42/42; 100%). Lumen dilatation caused focal vessel-wall flattening, which resulted in intimal necrosis. Multifocal necrosis extending from the intima to the media occurred in 23 out of 42 kidneys (55%) and peri-arterial edema with multifocal vascular leakage in 19 out of 42 kidneys (45%). At multivariable analysis, blocked-flow MS-NBCA injection was associated with greater severity of vessel-wall lesions, including intimal arteritis (P = 0.003) and intimal necrosis (P = 0.014), compared to free-flow injection. Blocked-flow injection was also associated with peri-arterial edema (P = 0.008) and greater distality of MS-NBCA penetration (P = 0.001). Conclusion: Blocked-flow MS-NBCA injection during renal artery embolization is significantly associated with more acute arterial-wall damage and greater distality of glue penetration compared to free-flow injection in a rabbit model. These preliminary findings may have clinical implications, as blocked-flow injection is routinely used to treat specific vascular diseases or malformations in human
Observer-based Adaptive Control for Slung Payload Stabilization with a Fully-actuated Multirotor UAV
No full textInternational audienceThis article presents an observer-based adaptive sliding mode controller for a fully-actuated hexacopter unmanned aerial vehicle, performing trajectory tracking in a perturbed environment while carrying a cable-suspended payload. Based on the unavailability of a payload swing sensor, an extended high-gain observer is designed, providing full-state and disturbance estimation including payload motion. Such disturbances are compensated into the control loop to dampen the oscillations, thus improving the flight performance of the hexacopter driven by the adaptive control, providing robustness against bounded perturbations and chattering reduction. The stability of the observer and the control method on this system is guaranteed through Lyapunov theory. Simulations using a multibody emulator demonstrate time reduction in payload dampening while controlling the aircraft trajectory, compared to a feedback regulation-based adaptive controller.</div