The Experts below are selected from a list of 8331 Experts worldwide ranked by ideXlab platform

G. P. Zou - One of the best experts on this subject based on the ideXlab platform.

  • Load Increment procedure for post‐buckling analysis of laminated plates under in‐plane Loads by finite strip method
    International Journal for Numerical Methods in Engineering, 2000
    Co-Authors: S.s.e. Lam, G. P. Zou
    Abstract:

    A Load Increment procedure has been presented to integrate with the finite strip method for the post-buckling analysis of laminated plates when subjected to uniform end shortening. In-plane Loads are introduced to reflect the end shortening effect. The Newton–Raphson procedure is implemented to attend a solution that satisfies the equilibrium condition and at the same time meets the Loading requirements. Error associated with Loading condition is minimised by adjusting the Load factor to preserve the rate of convergence. The enhanced capability can be easily incorporated into the context of both classical and shear deformation plate theories. A range of application has been described. Convergence test and numerical results are presented for isotropic plate and laminates with general lay-up arrangement. Copyright © 2000 John Wiley & Sons, Ltd.

  • Load Increment procedure for post buckling analysis of laminated plates under in plane Loads by finite strip method
    International Journal for Numerical Methods in Engineering, 2000
    Co-Authors: S.s.e. Lam, G. P. Zou
    Abstract:

    A Load Increment procedure has been presented to integrate with the finite strip method for the post-buckling analysis of laminated plates when subjected to uniform end shortening. In-plane Loads are introduced to reflect the end shortening effect. The Newton–Raphson procedure is implemented to attend a solution that satisfies the equilibrium condition and at the same time meets the Loading requirements. Error associated with Loading condition is minimised by adjusting the Load factor to preserve the rate of convergence. The enhanced capability can be easily incorporated into the context of both classical and shear deformation plate theories. A range of application has been described. Convergence test and numerical results are presented for isotropic plate and laminates with general lay-up arrangement. Copyright © 2000 John Wiley & Sons, Ltd.

Byung Man Kwak - One of the best experts on this subject based on the ideXlab platform.

  • Sensitivity analysis for automatic Loading in frictional contact formulated by complementarity
    Computers & Structures, 1993
    Co-Authors: Byung Man Kwak
    Abstract:

    Abstract With frictional contact problems, due to nonuniqueness and nonlinearity, the size of a Load Increment must be suitably determined to obtain the proper, physically meaningful path of response history. An automatic Load Increment method is proposed based on the sensitivity analysis of the solution with respect to the Load scale parameter. A two-dimensional problem is considered for clarity and the method is illustrated by numerical calculations. The results clearly indicate the nonuniqueness situation and the importance of a proper path-following method. The sensitivity is also used for the optimization of initial separations which can minimize the maximum contact pressure.

  • Periodic Loading in frictional contact formulated by complementarity
    International Journal of Solids and Structures, 1992
    Co-Authors: Bin Im, Byung Man Kwak
    Abstract:

    Abstract In the case of frictional contact problems subjected to periodic Loading, due to non-uniqueness and non-linearity, the size of a Load Increment must be suitably determined to obtain the proper, physically meaningful path of response history. A method of an automatic Load Increment is proposed based on the sensitivity analysis of the solution with respect to the Load scale parameter. Frictional contact conditions are formulated by complementarity and sensitivity analysis of the solutions with respect to the applied Load, using the parametric optimal design theory. As illustrative examples, a layer pressed against a half-plane by a uniform pressure and subjected to a tangential force varying periodically in time is tested and compared with the solutions by Comninou and Barber (1983, Int. J. Solids Structures19, 533–539). As a practical problem, a valve-cotter system of a small engine subjected to a periodic Loading is solved as a three body contact problem.

Z. Fawaz - One of the best experts on this subject based on the ideXlab platform.

  • Stepwise-equilibrium and adaptive molecular dynamics simulation for fracture toughness of single crystals
    Journal of Intelligent Material Systems and Structures, 2004
    Co-Authors: Gui-rong Liu, K. Behdinan, Z. Fawaz
    Abstract:

    A stepwise-equilibrium and adaptive molecular dynamics (MD) simulation scheme for investigating the fracture toughness of single crystals is proposed in this study. The critical fracture toughness is found by conducting MD simulations along with the gradually increasing external Load. At each Load step, an equilibrium state is obtained by relaxing the system from the initial state generated. This is done by adjusting the atomic position using an additional displacement of linear elastic solution corresponding to the current Load Increment. The Load Increment is adjusted at each step in an adaptive way in order to achieve high computational efficiency and accuracy. A nickel crystal having 14256 atoms is investigated using this technique. The critical stress intensity factor in the (1[UNKNOWN]0) plane is found to be 0.7436 MPa √m, while the fracture stress is 4.7776 GPa. The effects of vacancies on the critical stress intensity factors are also investigated.

S.s.e. Lam - One of the best experts on this subject based on the ideXlab platform.

  • Load Increment procedure for post‐buckling analysis of laminated plates under in‐plane Loads by finite strip method
    International Journal for Numerical Methods in Engineering, 2000
    Co-Authors: S.s.e. Lam, G. P. Zou
    Abstract:

    A Load Increment procedure has been presented to integrate with the finite strip method for the post-buckling analysis of laminated plates when subjected to uniform end shortening. In-plane Loads are introduced to reflect the end shortening effect. The Newton–Raphson procedure is implemented to attend a solution that satisfies the equilibrium condition and at the same time meets the Loading requirements. Error associated with Loading condition is minimised by adjusting the Load factor to preserve the rate of convergence. The enhanced capability can be easily incorporated into the context of both classical and shear deformation plate theories. A range of application has been described. Convergence test and numerical results are presented for isotropic plate and laminates with general lay-up arrangement. Copyright © 2000 John Wiley & Sons, Ltd.

  • Load Increment procedure for post buckling analysis of laminated plates under in plane Loads by finite strip method
    International Journal for Numerical Methods in Engineering, 2000
    Co-Authors: S.s.e. Lam, G. P. Zou
    Abstract:

    A Load Increment procedure has been presented to integrate with the finite strip method for the post-buckling analysis of laminated plates when subjected to uniform end shortening. In-plane Loads are introduced to reflect the end shortening effect. The Newton–Raphson procedure is implemented to attend a solution that satisfies the equilibrium condition and at the same time meets the Loading requirements. Error associated with Loading condition is minimised by adjusting the Load factor to preserve the rate of convergence. The enhanced capability can be easily incorporated into the context of both classical and shear deformation plate theories. A range of application has been described. Convergence test and numerical results are presented for isotropic plate and laminates with general lay-up arrangement. Copyright © 2000 John Wiley & Sons, Ltd.

Tong Gao - One of the best experts on this subject based on the ideXlab platform.

  • Topology optimization of elastic contact problems with friction using efficient adjoint sensitivity analysis with Load Increment reduction
    Computers & Structures, 2020
    Co-Authors: Cao Niu, Weihong Zhang, Tong Gao
    Abstract:

    Abstract This work presents a topology optimization method for the stiffness maximization design of elastic structures with frictional contact. The friction behavior is assumed to be governed by the Coulomb friction law regularized in analogy with the perfect elasto-plastic theory. To facilitate efficient adjoint sensitivity analysis, two Load Increment reduction (LIR) rules are proposed for sticking friction and pure sliding friction, and are validated by theoretical proof and numerical verification. The first rule is that any Load Increment whose set of sticking contact node pairs contains that of the Load Increment after can be skipped in the adjoint sensitivity analysis without influencing the final calculated sensitivities. The second one is that all Load Increments before the Load Increment in pure sliding friction can also be skipped. The implemented topology optimization procedure is validated by numerical examples. It is found that only the final Load Increment is needed in the overwhelming majority of iterations for all the tested cases based on the LIR rules. The computational burden of sensitivity analysis is thereby greatly reduced. Results also show that the optimized compliance generally decreases as the friction coefficient increases because the friction behavior helps to resist tangential deformations at the contact interface.