Search

This paper introduces a new stabilization algorithm to Lagrangian particle methods for the coupled thermal mechanical analysis in the friction drilling simulation. Different from the conventional penalty method which utilizes a direct smoothing of velocity fields in the weak formulation, the proposed algorithm introduces the smoothed velocity fields through linear momentum equations for stabilization. Particle approximations are used for the discretization of coupled thermal mechanical discrete equations. The coupled system is solved by the explicit and staggered time marching scheme. In comparison to the conventional penalty method which requires at least one extra integration point for stabilization, the proposed algorithm needs only one integration point per particle in computation. The essential features of linear and angular momentum conservations are preserved in the explicit dynamic analysis. A bridging scheme is also developed to couple the particle formulation with finite element formulation for practical industrial applications. Several benchmark tests are performed to examine the effectiveness of this new method. Furthermore, a friction drilling application is studied, and the results are compared with the experimental data. [ABSTRACT FROM AUTHOR]

In this paper, a numerical approach with an experimental validation is introduced for modelling high-speed metal grinding processes in 6061-T6 aluminum alloys. The derivation of the present numerical method starts with an establishment of a stabilized particle Galerkin approximation. A non-residual penalty term from strain smoothing is introduced as a means of stabilizing the particle Galerkin method. Additionally, second-order strain gradients are introduced to the penalized functional for the regularization of damage-induced strain localization problem. To handle the severe deformation in metal grinding simulation, an adaptive anisotropic Lagrangian kernel is employed. Finally, the formulation incorporates a bond-based failure criterion to bypass the prospective spurious damage growth issues in material failure and cutting debris simulation. A three-dimensional metal grinding problem is analyzed and compared with the experimental results to demonstrate the effectiveness and accuracy of the proposed numerical approach. [ABSTRACT FROM AUTHOR]

In this work, a strain-morphed nonlocal meshfree method is developed to overcome the computational challenges for the simulation of elastic-damage induced strain localization problem when the spatial domain integration is performed based on the background cells and Gaussian quadrature rule. The new method is established by introducing the decomposed strain fields from a meshfree strain smoothing to the penalized variational formulation. While the stabilization strain field circumvents the onerous zero-energy modes inherent in the direct nodal integration scheme, the regularization strain field aims to avoid the pathological localization of deformation in Galerkin meshfree solution using the weak-discontinuity approach. A strain morphing algorithm is introduced to couple the locality and non-locality of the decomposed strain approximations such that the continuity condition in the coupled strain field is met under the Galerkin meshfree framework using the direct nodal integration scheme. Three numerical benchmarks are examined to demonstrate the effectiveness and accuracy of the proposed method for the regularization of elastic-damage induced strain localization problems. [ABSTRACT FROM AUTHOR]

n efficient Galerkin meshfree formulation for three dimensional simulation of large deformation failure evolution in soils is presented. This formulation utilizes the stabilized conforming nodal integration, where for the purpose of stability and efficiency a Lagrangian smoothing strain at nodal point is constructed and thereafter the internal energy is evaluated nodally. This formulation ensures the linear exactness, efficiency and spatial stability in a unified manner and it makes the conventional Galerkin meshfree method affordable for three dimensional simulation. The three dimensional implementation of stabilized conforming nodal integration is discussed in details. To model the failure evolution in soil medium a coupled elasto-plastic damage model is used and an objective stress integration algorithm in combination of elasto-damage predictor and plastic corrector method is employed for stress update. Two typical numerical examples are shown to demonstrate the effectiveness of the present method for modeling large deformation soil failure. [ABSTRACT FROM AUTHOR]