The Experts below are selected from a list of 225 Experts worldwide ranked by ideXlab platform

Hexin Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Topology Optimization of Structures with Elasto-Plastic Strain Hardening Material Modeling
    Advances in Structural and Multidisciplinary Optimization, 2017
    Co-Authors: Hexin Zhang
    Abstract:

    The objective of this paper is to investigate the influence of the plastic model and the hardening rules adopted for a multiphase material structure on the resulting topologies by incorporating the elastoplasticity material models into the density-based topology optimization. A topology optimization method associated with multiphase elastoplastic materials is developed to maximize the load capacity under a Prescribed Displacement. This method enables optimizing a design domain composed of two-phase material composites, in which each material may has a specific plastic model. Particularly, by applying the von Mises and the Drucker-Prager yielding criterion to each material and adopting kinematic hardening rules. The interpolations of the elastic and the plastic response are achieved by applying dependency on the design variable to both elastic modulus and yield function. The sensitivity of the stated optimization problem is derived using a path-dependent adjoint method. The capability of the proposed optimization framework is presented through two numerical examples. From the results, it can be concluded that opposite to the post yielding behavior of strain-hardening having negligible effect on the resulting topologies, the type of yield criterion chosen for the material modeling and the magnitude of the Prescribed Displacement applied to the structure have a significant influence on the optimized layout.

Olivier Pitois - One of the best experts on this subject based on the ideXlab platform.

  • Quasistatic detachment of a sphere from a liquid interface
    Journal of colloid and interface science, 2003
    Co-Authors: Xavier Chateau, Olivier Pitois
    Abstract:

    Abstract In this paper the problem of removing a spherical particle initially attached to a liquid–gas interface is analytically treated. In particular, the Derjaguin equation for small radii is used to derive a closed-form approximate expression for the work of detachment of the sphere from the interface. Expressions corresponding to the Prescribed Displacement condition and the applied force condition, which seems to be the relevant condition for the flotation separation process, are presented. A special effort has been made to closely compare analytical results with data obtained through the exact numerical treatment of the detachment process. Results show that proposed expressions are sufficiently accurate to calculate the energy required to detach the sphere from the interface as soon as the sphere radius is small compared to the capillary length. Validity limits are specified.

  • Quasistatic detachment of a sphere from a liquid interface
    Journal of Colloid and Interface Science, 2003
    Co-Authors: Xavier Chateau, Olivier Pitois
    Abstract:

    In this paper the problem of removing a spherical particle initially attached to a liquid-gas interface is analytically treated. In particular, the Derjaguin equation for small radii is used to derive a closed-form approximate expression for the work of detachment of the sphere from the interface. Expressions corresponding to the Prescribed Displacement condition and the applied force condition, which seems to be the relevant condition for the flotation separation process, are presented. A special effort has been made to closely compare analytical results with data obtained through the exact numerical treatment of the detachment process. Results show that proposed expressions are sufficiently accurate to calculate the energy required to detach the sphere from the interface as soon as the sphere radius is small compared to the capillary length. Validity limits are specified. (C) 2003 Elsevier Science (USA). All rights reserved.

Tomotaka Ogasawara - One of the best experts on this subject based on the ideXlab platform.

  • Localization simulation of a representative volume element with Prescribed Displacement boundary for investigating the thermal residual stresses of composite forming
    Composite Structures, 2020
    Co-Authors: Hongzhou Zhai, Nobuhiro Yoshikawa, Tomotaka Ogasawara
    Abstract:

    Abstract In this research, a methodology of localization simulation that not only discriminately described fiber and resin but also considered the global influence like external temperature loading was introduced. The newly proposed representative volume element with a Prescribed Displacement boundary that was deduced from a generalized viscoelastic shear lag model can link the macro and micro models if the edge effect was ignored. After the material models and software platform were demonstrated through a composite warpage experiment, the proposed localization simulation was investigated by comparing to a large-scale fully microscale benchmark model in an ideal cooling phase. The results show that the temperature and residual stresses evaluated from the new technique not only presented details fine to the scale of the representative volume element but also included the macroscopic temperature gradient, indicating a promising way to understand the composite forming process in a comprehensive format.

Reis, Pedro M. - One of the best experts on this subject based on the ideXlab platform.

  • Technical Brief: Finite Element Modeling of Tight Elastic Knots
    'ASME International', 2020
    Co-Authors: Baek Changyeob, Johanns Paul, Sano, Tomohiko G., Grandgeorge Paul, Reis, Pedro M.
    Abstract:

    We present a methodology to simulate the mechanics of knots in elastic rods using geometrically nonlinear, full three-dimensional (3D) finite element analysis. We focus on the mechanical behavior of knots in tight configurations, for which the full 3D deformation must be taken into account. To set up the topology of our knotted structures, we apply a sequence of Prescribed Displacement steps to the centerline of an initially straight rod that is meshed with 3D solid elements. Self-contact is enforced with a normal penalty force combined with Coulomb friction. As test cases, we investigate both overhand and figure-of-eight knots. Our simulations are validated with precision model experiments, combining rod fabrication and X-ray tomography. Even if the focus is given to the methods, our results reveal that 3D deformation of tight elastic knots is central to their mechanical response. These findings contrast to a previous analysis of loose knots, for which 1D centerline-based rod theories sufficed for a predictive understanding. Our method serves as a robust framework to access complex mechanical behavior of tightly knotted structures that are not readily available through experiments nor existing reduced-order theories

  • Finite Element Modeling of Tight Elastic Knots
    'ASME International', 2020
    Co-Authors: Baek Changyeob, Johanns Paul, Sano, Tomohiko G., Grandgeorge Paul, Reis, Pedro M.
    Abstract:

    We present a methodology to simulate the mechanics of knots in elastic rods using geometrically nonlinear, full three-dimensional (3D) finite element analysis. We focus on the mechanical behavior of knots in tight configurations, for which the full 3D deformation must be taken into account. To setup the topology of our knotted structures, we apply a sequence of Prescribed Displacement steps to the centerline of an initially straight rod that is meshed with 3D solid elements. Self-contact is enforced with a normal penalty force combined with Coulomb friction. As test cases, we investigate both overhand and figure-of-eight knots. Our simulations are validated with precision model experiments, combining rod fabrication and X-ray tomography. Even if the focus is given to the methods, our results reveal that 3D deformation of tight elastic knots is central to their mechanical response. These findings contrast to a previous analysis of loose knots, for which 1D centerline-based rod theories sufficed for a predictive understanding. Our method serves as a robust framework to access complex mechanical behavior of tightly knotted structures that are not readily available through experiments nor existing reduced-order theories

Xavier Chateau - One of the best experts on this subject based on the ideXlab platform.

  • Quasistatic detachment of a sphere from a liquid interface
    Journal of colloid and interface science, 2003
    Co-Authors: Xavier Chateau, Olivier Pitois
    Abstract:

    Abstract In this paper the problem of removing a spherical particle initially attached to a liquid–gas interface is analytically treated. In particular, the Derjaguin equation for small radii is used to derive a closed-form approximate expression for the work of detachment of the sphere from the interface. Expressions corresponding to the Prescribed Displacement condition and the applied force condition, which seems to be the relevant condition for the flotation separation process, are presented. A special effort has been made to closely compare analytical results with data obtained through the exact numerical treatment of the detachment process. Results show that proposed expressions are sufficiently accurate to calculate the energy required to detach the sphere from the interface as soon as the sphere radius is small compared to the capillary length. Validity limits are specified.

  • Quasistatic detachment of a sphere from a liquid interface
    Journal of Colloid and Interface Science, 2003
    Co-Authors: Xavier Chateau, Olivier Pitois
    Abstract:

    In this paper the problem of removing a spherical particle initially attached to a liquid-gas interface is analytically treated. In particular, the Derjaguin equation for small radii is used to derive a closed-form approximate expression for the work of detachment of the sphere from the interface. Expressions corresponding to the Prescribed Displacement condition and the applied force condition, which seems to be the relevant condition for the flotation separation process, are presented. A special effort has been made to closely compare analytical results with data obtained through the exact numerical treatment of the detachment process. Results show that proposed expressions are sufficiently accurate to calculate the energy required to detach the sphere from the interface as soon as the sphere radius is small compared to the capillary length. Validity limits are specified. (C) 2003 Elsevier Science (USA). All rights reserved.