Publications

2024

• A time-domain spectral finite element method for acoustoelasticity: modeling the effect of mechanical loading on guided wave propagation
  
  • Dalmora Andre Luiz
  • Imperiale Alexandre
  • Imperiale Sébastien
  • Moireau Philippe
  Wave Motion, Elsevier, 2024, 129, pp.103328 (23 p.). Ultrasonic testing techniques such as guided wave-based structural health monitoring aim to evaluate the integrity of a material with sensors and actuators that operate in situ, i.e. while the material is in use. Since ultrasonic wave propagation is sensitive to environmental conditions such as pre-deformation of the structure, the design and performance evaluation of monitoring systems in this context is a complicated task that requires quantitative data and the associated modeling effort. In our work, we propose a set of numerical tools to solve the problem of mechanical wave propagation in materials subjected to pre-deformation. This type of configuration is usually treated in the domain of acoustoelasticity. A relevant modeling approach is to consider two different problems: a quasi-static nonlinear problem for the large displacement field of the structure and a linearized time-domain wave propagation problem. After carefully reviewing the modeling ingredients to represent the configurations of interest, we propose an original combination of numerical tools that leads to a computationally efficient algorithm. More specifically, we use 3D shell elements for the quasi-static nonlinear problem and the time-domain spectral finite element method to numerically solve the wave propagation problem. Our approach can represent any type of material constitutive law, geometry or mechanical solicitation. We present realistic numerical results on 3D cases related to the monitoring of both isotropic and anisotropic materials, illustrating the genericity and efficiency of our method. We also validate our approach by comparing it to experimental data from the literature. (10.1016/j.wavemoti.2024.103328)
  DOI : 10.1016/j.wavemoti.2024.103328
• Very fast simulation of growth competition between columnar dendritic grains during melt pool solidification
  
  • Dollé Quentin
  • Weisz-Patrault Daniel
  Computational Materials Science, Elsevier, 2024, 243, pp.113112. This paper presents a very fast numerical approach to simulate microstructures resulting from melt pool solidification including growth competition of columnar dendritic grains, and equiaxed grains nucleated from the melt. To reduce computation time, the key contribution is the development of an upscaling strategy, which instead of considering each dendrite individually consists in defining an average solidification front based on physically-informed dendritic growth velocity. The proposed approach also relies on dendritic preferred growth direction, and favorably oriented grain criterion to determine which grain survives the competition. To significantly reduce the total number of degrees of freedom Voronoi tessellations are used instead of regular grids for numerical implementation. Indeed, 3D regular grids typically leads to ${N}^3$ degrees of freedom while Voronoi tessellations lead to only 3${N}$, which dramatically reduces computation cost. This work is therefore a high-throughput approach enabling large data set generation to explore statistical features of microstructures with respect to melt pool properties. Results have been compared to experimental data, and to phase field and cellular automaton simulations in 2D only. Simulated microstructures are similar as those obtained with cellular automaton. Comparisons in 3D are left for future work. In addition, a convergence analysis is provided for 3D simulations, with thermal conditions corresponding to metal additive manufacturing to demonstrate how the present work can be used in practice. (10.1016/j.commatsci.2024.113112)
  DOI : 10.1016/j.commatsci.2024.113112
• Three‐dimensional multiscale assembly of phyllosilicates, organics, and carbonates in small Ryugu fragments
  
  • Dionnet Zelia
  • Rubino Stefano
  • Aléon-Toppani Alice
  • Brunetto Rosario
  • Tsuchiyama Akira
  • Lantz Cateline
  • Djouadi Zahia
  • Baklouti Donia
  • Nakamura Tomoki
  • Borondics Ferenc
  • Sandt Christophe
  • Héripré Eva
  • Troadec David
  • Mivumbi Obadias
  • Aléon Jérome
  • Ternier Theo
  • Matsumoto Megumi
  • Amano Kana
  • Morita Tomoyo
  • Yurimoto Hisayoshi
  • Noguchi Takaaki
  • Okazaki Ryuji
  • Yabuta Hikaru
  • Naraoka Hiroshi
  • Sakamoto Kanako
  • Tachibana Shogo
  • Yada Toru
  • Nishimura Masahiro
  • Nakato Aiko
  • Miyazaki Akiko
  • Yogata Kasumi
  • Abe Masanao
  • Okada Tatsuaki
  • Usui Tomohiro
  • Yoshikawa Makoto
  • Saiki Takanao
  • Tanaka Satoshi
  • Terui Fuyuto
  • Nakazawa Satoru
  • Watanabe Seiichiro
  • Tsuda Yuichi
  Meteoritics and Planetary Science, Wiley, 2024, 59 (8), pp.1859-1876. We report μm‐scale nondestructive infrared (IR) hyperspectral results (IR computed tomography, IR‐CT) in 3‐D and IR surface imaging, IR‐S) in 2‐D, at SOLEIL) combined with X‐ray nano‐computed tomography analyses (at SPring‐8) performed on eight small Ryugu fragments extracted from mm‐sized grains coming both from touchdown first and second sites. We describe the multiscale assembly of phyllosilicates, carbonates, sulfides, oxides, and organics. Two types of silicates, as well as diverse kinds of organic matter, were detected inside Ryugu material. Their spatial correlations are described to discuss the role of the mineralogical microenvironments in the formation/evolution of organic matter. In particular, we have shown that there is a redistribution of the organic matter diffuse component during aqueous alteration on the parent body, with a preferential circulation among fine‐grained phyllosilicates. (10.1111/maps.14068)
  DOI : 10.1111/maps.14068
• Asymptotic, second-order homogenization of linear elastic beam networks
  
  • Ye Yang
  • Audoly Basile
  • Lestringant Claire
  Journal of the Mechanics and Physics of Solids, Elsevier, 2024, 188, pp.105637. We propose a general approach to the higher-order homogenization of discrete elastic networks made up of linear elastic beams or springs in dimension 2 or 3. The network may be nearly (rather than exactly) periodic: its elastic and geometric properties are allowed to vary slowly in space, in addition to being periodic at the scale of the unit cell. The reference configuration may be prestressed. A homogenized strain energy depending on both the macroscopic strain ɛ and its gradient ∇ɛ is obtained by means of a two-scale expansion. The homogenized energy is asymptotically exact two orders beyond that obtained by classical homogenization. The homogenization method is implemented in a symbolic calculation language and applied to various types of networks, such as a 2D honeycomb, a 2D Kagome lattice, a 3D truss and a 1D pantograph. It is validated by comparing the predictions of the microscopic displacement to that obtained by full, discrete simulations. This second-order method remains highly accurate even when the strain gradient effects are significant, such as near the lips of a crack tip or in regions where a gradient of pre-strain is imposed. (10.1016/j.jmps.2024.105637)
  DOI : 10.1016/j.jmps.2024.105637