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Universal constructions in homotopical algebra
No full textWe apply the effective integration theory of Lie-graph algebras, developed recently by the authors, to the deformation and homotopy theories of types of bialgebras, that is structures controlled by a properad, like associative bialgebras, (involutive) Lie bialgebras, Frobenius bialgebras, double Poisson bialgebras, pre-Calabi--Yau algebras, quantum Airy structures, etc. In these cases, we provide their associated Deligne groupoid with an explicit homotopical description. We settle the Koszul hierarchy and the twisting procedure on the properadic level. We also give a conceptual construction of the homotopy transfer theorem in terms of gauge actions. This work extends the formulas for the deformation theory of operadic algebras
Experimental and Numerical Study of Near-Field Explosion with Small Charges on Composite Structure
No full textInternational audienceAbstract The main purpose of this publication is to study the pressure generated by a near-field explosive charge, for example placed close to an aircraft composite fuselage. Representing explosive charges in the near-field is a crucial problem when it comes to analyzing the vulnerability of a composite structure subjected to such a dynamic load. The air blast experimental tests revealed saturation of the sensors in the near-field area. Two conditions of pressure measurements are investigated, one for the classical indicator called reduced distance W equals to 0.81 m/kg 1/3 and another one in the far-field. For reasons of confidentiality, information on the mass of the explosive and its distance from the target is not given and is normalized using arbitrary quantities. This is the case for all values used to calculate the mass of the explosive and its distance from the target. The paper shows how to take advantage of a situation where the explosive charge does not completely disable the near-field sensors. It is about the development of an original approach, gathering experience and calculations to model a representative pressure-time history. Partial experimental measurements are extrapolated using Eulerian numerical simulations performed by French CEA DAM’s Ouranos hydrocode. The operational character of the extrapolation is demonstrated by comparing the results of the simulation with experimental data gathered by the far-field sensors. Finally, these pressures measured will be used to investigate the structural response of an aeronautical composite structure under the near-field blast. The experimental work involves accurate instrumentation of a representative composite structure (through the MITE concept), high-speed measurements using both digital image correlation and Doppler laser interferometry, and carefully positioned pressure sensors, including in the near-field zone where sensor damage is likely. The divergent 1D spherical blast computed using the Eulerian component of the Ouranos hydrocode is then mapped into a 3D blast wave used to load the composite structure. The structural response is modeled in Abaqus/Explicit with cohesive elements between composite plies, allowing for delamination. The results are qualitatively compared with experimental displacement measurements and post-mortem ultrasonic analyses and show promising agreement
Time evolution of controlled many-body quantum systems with matrix product operators
No full textWe present a method for describing the time evolution of many-body controlled quantum systems using matrix product operators (MPOs). Existing techniques for solving the time-dependent Schrödinger equation (TDSE) with an MPO Hamiltonian often rely on time discretization. In contrast, our approach uses the Magnus expansion and Chebyshev polynomials to model the time evolution, and the MPO representation to efficiently encode the system's dynamics. This results in a scalable method that can be used efficiently for many-body controlled quantum systems. We apply this technique to quantum optimal control, specifically for a gate synthesis problem, demonstrating that it can be used for large-scale optimization problems that are otherwise impractical to formulate in a dense matrix representation
Coacervation and aggregation in lysozyme/alginate mixtures
No full textInternational audienceUpon electrostatic interactions, the mixture of oppositely charged macromolecules separates into a macromolecule-rich phase coexisting with a diluted phase. The phase separation is either a liquid-liquid phase separation (LLPS) forming complex coacervates, or a liquid-solid phase separation (LSPS) forming aggregates. Here, we investigate the assembly of the positively charged protein lysozyme (LYS) with the negatively charged polysaccharide alginate (ALG) at pH 7 under different conditions of mixing ratios, total concentration, and ionic strength using a droplets-based millifluidic device. A 3D phase diagram, with the concentrations of salt, lysozyme, and alginate as the 3D coordinates, gives a thorough description of the monophasic, liquid-solid, and liquid-liquid phase separation areas and the regions where both solid and liquid phases coexist. The thermodynamic aspects behind these two kinds of complex formation are investigated using isothermal titration calorimetry (ITC). Aggregation is associated with a strong affinity between LYS and ALG, with a 100 LYS : 1 ALG stoichiometry ratio, whereas coacervation at higher salt concentration is asso- ciated to a strong decrease of the binding affinity between the two biopolymers
Shear and Compression Wrinkling Experimental Analysis with a Sandwich Beam Submitted to Three-Point Bending
No full textInternational audienceWrinkling is a localized buckling phenomenon that significantly compromises the structural integrity of lightweight sandwich structures. The objective of this study was to validate the experimental design of a sandwich beam to observe the initiation of wrinkling under compression and, more specifically, under shear stresses. The specimen under consideration consists of glass fibre–epoxy skins with polymethacrylimide (PMI) ROHACELL® foam cores. The experimental tests were monitored using Digital Image Correlation (DIC) techniques, in conjunction with displacement and force sensors. A linear buckling simulation was performed using Finite Element Analysis (FEA) in ABAQUS and was compared with both the experimental test results and analytical predictions. The simulations demonstrated a good correlation with both the experimental data and analytical models for compression wrinkling. In the case of shear wrinkling, the numerical analysis significantly overestimated the wrinkling load in comparison to the experimental results
Synergy between microstructure anisotropy and size effects on the ductile failure of Hastelloy X printed by Laser Power Bed Fusion
No full textInternational audienceThis work addresses the effect of the microstructural anisotropy, both morphological and crystallographic due to fabrication strategy, and the size-effects on the fracture behavior of Hastelloy X superalloys printed by Laser Power Bed Fusion (LPBF-HX). It aims at specifically investigating the role played by crack orientation (perpendicular or co-linear to sample lasing planes) on the fracture toughness values of LPBF-HX. Micro-cantilever bending tests have been conducted on vertically or horizontally built specimens to estimate the fracture toughness at the microscopic scale depending on the initial notch orientation. LPBF-HX results in complex microstructural features at the micro- and mesoscale, which significantly impair the fracture mechanisms. At both microscopic and macroscopic scales, cracking occurs along with a ductile tearing. A simple analytical model has been applied to account for the size effect on the fracture behavior depending on the building direction and notch orientation. This model provides internal characteristic lengths, , which is a key parameter for transition rules from small to large scale. In horizontal specimens, the value of is equal to 1.33 mm, whereas it slightly increases to 1.57 mm in vertical specimens. The knowledge of the size effect law using internal characteristic lengths is crucial for the determination of the R-curve at different scales
Pinch line spin liquids as layered Coulomb phases and applications to cubic models
No full textInternational audienceSpin liquids form fluctuating magnetic textures which have to obey certain rules imposed by frustration. These rules can often be written in the form of a Gauss law, indicating the local conservation of an emergent electric field. In reciprocal space, these emergent Gauss laws appear as singularities known as pinch points that are accessible to neutron-scattering measurements. But more exotic forms of electromagnetism have been stabilized in spin liquids, and in a few rare instances, these zero-dimensional singularities have been extended into one-dimensional pinch lines. Here we propose a simple framework for the design of pinch line spin liquids in a layered structure of two-dimensional algebraic spin liquids. A plethora of models can be build within this framework, as exemplified by several concrete examples where our theory is confirmed by simulations, and where the rank of the tensorial gauge field is continuously varied along the pinch line, opening new avenues in fractonic matter. Then we use our framework to understand how the evolution of the singularity pinch point along the pinch line can be understood as the interference pattern of two emergent electric fields. Finally, we apply our intuition on these emergent electric fields in real space to generic pinch line models beyond our layered framework and revisit the recently proposed pinch line model on the octochlore lattice
Développement de mousses thermoplastiques réactives pour applications dans panneaux sandwich multifonctionnels
No full textInternational audienceLes panneaux sandwich multifonctionnels sont une classe de matériaux composites qui permettent d'intégrer des fonctions secondaires dans une structure porteuse. L'isolation acoustique ou encore la résistance à l'impact sont des propriétés fortement dépendantes des matériaux d'âme et plus particulièrement de leur microstructure. Afin de développer des nouvelles solutions plus respectueuses de l'environnement d'un point de vue du cycle de vie, cette étude propose d'explorer une technique de moussage novatrice pour obtenir des matériaux d'âme à partir d'une résine thermoplastique réactive Elium ® C195E. L'idée de base consiste à exploiter le teneur élevé du monomère méthacrylate de méthyl (MMA) dans le mélange réactif (75-80%), sa faible température d'ébullition (101°C), ainsi que la forte réactivité après mélange du système pour obtenir une mousse thermoplastique à faible densité. Les premiers résultats sont encourageants et ont permis d'obtenir plusieurs échantillons dans un moule fermé avec une bonne stabilité dimensionnelle. La microstructure observée après enrobage et polissage reste assez hétérogène, avec des pores de grosses dimensions d'environ 2 mm. Les prochaines campagnes d'essais mécaniques, acoustiques et à la tour de chute permettront de déterminer les applications potentielles ainsi que de déligner des potentielles voies d'amélioration pour pouvoir intégrer ces matériaux d'âme dans des panneaux sandwich multifonctionnels
