Thuy Nguyen

@article{nguyen_3192,

title = {Size-dependency and lattice-discreetness effect on fracture toughness in 2D crystals under antiplanar loading},

author = {Thuy Nguyen and Daniel Bonamy},

url = {https://link.springer.com/article/10.1007/s10704-024-00812-4?utm_source=rct_congratemailt&utm_medium=email&utm_campaign=oa_20241017&utm_content=10.1007%2Fs10704-024-00812-4},

year  = {2024},

date = {2024-10-01},

journal = {International Journal Of Fracture},

abstract = {Fracture toughness is the material property

characterizing resistance to failure. Predicting its value from the solid structure at the atomistic scale remains elusive, even in the simplest situations of brittle fracture. We report here numerical simulations of crack propagation in two-dimensional fuse networks of different periodic geometries, which are electrical analogs of bidimensional brittle crystals under antiplanar loading. Fracture energy is determined from Griffith's analysis of energy balance during crack propagation, and fracture toughness is determined from fits of the displacement fields with Williams' asymptotic solutions. Significant size dependencies are evidenced in small lattices, with fracture energy and fracture toughness both converging algebraically with system size toward well-defined material-constant values in the limit of infinite system size. The convergence speed depends on the loading conditions and is faster when the symmetry of the considered lattice increases. The material

constants at infinity obey Irwin's relation and properly define the material resistance to failure. Their values are approached up to ? 15% using the recent analytical method proposed in Nguyen and Bonamy (Phys

Rev Lett 123:205503, 2019). Nevertheless, the deviation remains finite and does not vanish when the system size goes to infinity. We finally show that this deviation is a consequence of the lattice discreetness and

decreases when the super-singular terms of Williams' solutions (absent in a continuum medium but present here due to lattice discreetness) are taken into account.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{rmili_2653,

title = {New empirical test method to assess Reynolds dilatancy of concrete under free-surface flow},

author = {Yosra Rmili and Tien Tung Ngo and El-Hadj Kadri and Ammar Yahia and Masoud Hosseinpoor and Thuy Nguyen},

url = {https://www.sciencedirect.com/science/article/pii/S0950061823044835?via%3Dihub},

year  = {2024},

date = {2024-01-01},

journal = {Construction And Building Materials},

volume = {411},

pages = {134762},

abstract = {In this study, a new test method was proposed to evaluate the shear-induced volumetric changes, namely Reynolds dilatancy (RD), of sixteen conventional vibrated concrete (CVC) mixtures under free-surface flow. The RD measurements were carried out using a rheometer set-up and different vane-blade types rotating at different speeds. According to the experimental results, the RD values were found in good agreement with the workability of the investigated mixtures. Moreover, the RD values were well correlated with the coupled effect of the relative solid packing fraction of coarse aggregate (?/?max) and viscoplastic properties of the investigated CVC mixtures. Furthermore, a strong correlation was established between the rheological properties of the lubrication layer, RD values, and the ?/?max of coarse aggregate.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{schittecatte_2327,

title = {From resin formulation and process parameters to the final mechanical properties of 3D printed acrylate materials},

author = {Laura Schittecatte and Valérie Geertsen and Daniel Bonamy and Thuy Nguyen and Patrick Guenoun},

url = {https://link.springer.com/article/10.1557/s43579-023-00352-3},

year  = {2023},

date = {2023-04-01},

journal = {Mrs Communications},

volume = {13},

pages = {357-377},

abstract = {Photopolymerizable resins are increasingly used to generate complex 3D printed parts through stereo lithography, digital light processing (DLP) and

liquid crystal display (LCD) 3D printing. Many challenges relating to the resin chemistry and printing parameters still exist and must be addressed in order to entirely control the properties of parts after printing. This work reviews the current knowledge and describes the potential of DLP/LCD methods for printed acrylate resins, as well as the steps necessary to achieve a better control over the mechanical properties of printed materials.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{montiel_1922,

title = {Effect of architecture disorder on the elastic response of two-dimensional lattice materials},

author = {Antoine Montiel and Thuy Nguyen and Cindy Rountree and Valérie Geertsen and Patrick Guenoun and Daniel Bonamy},

url = {https://journals.aps.org/pre/abstract/10.1103/PhysRevE.106.015004?ft=1},

year  = {2022},

date = {2022-07-01},

journal = {Physical Review E},

volume = {106},

number = {1},

pages = {015004},

abstract = {We examine how disordering joint position influences the linear elastic behavior of lattice materials via numerical simulations in two-dimensional beam networks. Three distinct initial crystalline geometries are selected as representative of mechanically isotropic materials with low connectivity, mechanically isotropic materials with high connectivity, and mechanically anisotropic materials with intermediate connectivity. Introducing disorder generates spatial fluctuations in the elasticity tensor at the local (joint) scale. Proper coarse-graining reveals a well-defined continuum-level scale elasticity tensor. Increasing disorder aids in making initially anisotropic materials more isotropic. The disorder impact on the material stiffness depends on the lattice connectivity: Increasing the disorder softens lattices with high connectivity and stiffens those with low connectivity, without modifying the scaling between elastic modulus and density (linear scaling for high connectivity and cubic scaling for low connectivity). Introducing disorder in lattices with intermediate fixed connectivity reveals both scaling: the linear scaling occurs for low density, the cubic one at high density, and the crossover density increases with disorder. Contrary to classical formulations, this work demonstrates that connectivity is not the sole parameter governing elastic modulus scaling. It offers a promising route to access novel mechanical properties in lattice materials via disordering the architectures.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nguyen_1496,

title = {Role of the Crystal Lattice Structure in Predicting Fracture Toughness},

author = {Thuy Nguyen and Daniel Bonamy},

url = {https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.123.205503},

year  = {2019},

date = {2019-11-01},

journal = {Physical Review Letters},

volume = {123},

number = {20},

pages = {205503},

abstract = {We examine the atomistic scale dependence of a material's resistance to failure by numerical simulations and analytical analysis in electrical analogs of brittle crystals. We show that fracture toughness depends on the lattice geometry in a way incompatible with Griffith's relationship between fracture and free surface energy. Its value finds its origin in the matching between the continuum displacement field at the engineering scale, and the discrete nature of solids at the atomic scale. The generic asymptotic form taken by this field near the crack tip provides a solution for this matching, and subsequently a way to predict toughness from the atomistic parameters with application to graphene},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nguyen_2747,

title = {Approximating the asymmetric profitable tour},

author = {Viet Hung Nguyen and Thuy Nguyen},

url = {https://www.sciencedirect.com/science/article/pii/S1571065310001162},

year  = {2012},

date = {2012-04-01},

journal = {International Journal of Mathematics in Operational Research},

volume = {4},

pages = {294-301},

abstract = {We study the version of the asymmetric prize collecting travelling salesman problem, where the objective is to find a directed tour that visits a subset of vertices such that the length of the tour plus the sum of penalties associated with vertices not in the tour is as small as possible. In Dell'Amico et al. (1995), the authors defined it as the Profitable Tour Problem (PTP). We present an (1 + ?log( n )?)-approximation algorithm for the asymmetric PTP with n is the vertex number. The algorithm that is based on Frieze et al.'s heuristic for the asymmetric travelling salesman problem as well as a method to round fractional solutions of a linear programming relaxation to integers (feasible solution for the original problem), represents a directed version of the Bienstock et al.'s (1993) algorithm for the symmetric PTP.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nguyen_2745,

title = {Scaling and universality in the kinetic smoothening of interfaces: Application to the analysis of the relaxation of rough vicinal steps of an oxide surface},

author = {Thuy Nguyen and Daniel Bonamy and Laurent Pham Van and Jacques Cousty and Luc Barbier},

url = {https://iopscience.iop.org/article/10.1209/0295-5075/89/60005/meta},

year  = {2010},

date = {2010-04-01},

journal = {Epl},

volume = {89},

pages = {60005},

abstract = {Relaxation of initially out-of-equilibrium rough interfaces in the presence of thermal noise is investigated using Langevin formalism. During thermal equilibration towards the well-known roughening regime, three scaling regimes observed over three successive ranges of length-scales are evidenced: thermal roughening (late stage) at small scales, transient smoothening at intermediate scales and remnant of the initial conditions at large scales. A generalization of the Family-Vicsek scaling is found for the smoothening regime. This approach allows interpreting a series of AFM images of sapphire surfaces showing the thermal evolution of initially rough step edges.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nguyen_2746,

title = {Coarsening of two-dimensional Al2O3 islands on vicinal (1, -1, 0, 2) sapphire surfaces during annealing in air},

author = {Thuy Nguyen and Daniel Bonamy and Laurent Pham Van and Luc Barbier and Jacques Cousty},

url = {https://www.sciencedirect.com/science/article/pii/S0039602808005645},

year  = {2008},

date = {2008-11-01},

journal = {Surface Science},

volume = {602},

number = {21},

pages = {3232-3238},

abstract = {The evolution of two-dimensional (2D) islands which result from a chemo-mechanical polishing of vicinal (1, ?1, 0, 2) sapphire surfaces was explored by atomic force microscopy (AFM) after annealing in air. The evolution of the surface morphology is followed after isothermal annealing (1173 K) for duration varying from 1 h to 53 h and isochronal annealing at temperatures between 1023 K < T < 1253 K. Statistical analysis of the AFM images gives evidence that an anisotropic Ostwald ripening governs the evolution of the 2D island distribution. The activation energy for mass transport on the terrace is found to be 1.3 ± 0.1 eV.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}