scholarly journals Numerical Study of Dynamic Properties of Fractional Viscoplasticity Model

Symmetry ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 282 ◽  
Author(s):  
Michał Szymczyk ◽  
Marcin Nowak ◽  
Wojciech Sumelka
Keyword(s):  
Numerical Study ◽  
Dynamic Properties ◽  
Plastic Anisotropy ◽  
Time Integration ◽  
Comprehensive Analysis ◽  
Implicit Time ◽  
Integration Scheme ◽  
Viscoplastic Model ◽  
Time Integration Scheme ◽  
Non Locality

The fractional viscoplasticity (FV) concept combines the Perzyna type viscoplastic model and fractional calculus. This formulation includes: (i) rate-dependence; (ii) plastic anisotropy; (iii) non-normality; (iv) directional viscosity; (v) implicit/time non-locality; and (vi) explicit/stress-fractional non-locality. This paper presents a comprehensive analysis of the above mentioned FV properties, together with a detailed discussion on a general 3D numerical implementation for the explicit time integration scheme.

Numerical Analysis of Solute Segregation in Directional Solidification under Static Magnetic Field

2011 ◽  
Vol 312-315 ◽  
pp. 253-258 ◽  
Author(s):  
Sabrina Nouri ◽  
Mouhamed Benzeghiba ◽  
Ahmed Benzaoui
Keyword(s):  
Magnetic Field ◽  
Static Magnetic Field ◽  
Time Integration ◽  
Magnetic Field Effect ◽  
Computer Code ◽  
Thermosolutal Convection ◽  
Implicit Time ◽  
Integration Scheme ◽  
Dimensional Solution ◽  
Time Integration Scheme

This paper addresses the effect of thermosolutal convection in the formation of defects in directionally solidified alloys. The numerical model is based on a bi-dimensional solution consisting of an implicit time integration scheme to couple thermal and solutal fields, which is supported by a finite volume numerical modeling technique. In this article, the macrosegregation phenomenon under a static magnetic field effect is analyzed numerically by a computer code developed and validated with experimental data. The numerically obtained results have been widely discussed in dependence of the characteristic parameters of the studied problem.

Dynamics of Disconnected Risers Under Rigid and Compliant Hang-Off

1990 ◽  
Vol 112 (2) ◽  
pp. 106-114
Author(s):  
N. M. Patrikalakis ◽  
D. Y. Yoon
Keyword(s):  
Efficient Solution ◽  
Time Integration ◽  
Implicit Time ◽  
Integration Scheme ◽  
Nonuniform Grid ◽  
Implicit Time Integration ◽  
Time Integration Scheme ◽  
Type Response ◽  
Nonlinear Motions ◽  
Excitation Conditions

An efficient solution scheme to simulate the nonlinear motions of hanging risers based on an adaptive nonuniform grid finite difference method and an implicit time integration scheme is presented. Dynamic buckling-type response of hanging risers under rigid hang-off due to heave acceleration of the support platform in extreme excitation conditions is studied, and the important parameters affecting the response are identified. Significant reduction of motions and resulting stresses is obtained by employing compliant hang-off.

Studies on the Accuracy Stability and Efficiency of a New Time Integration Scheme for Ballast Modeling Using the Discrete Element Method

2014 ◽  
Author(s):  
G. F. Mathews ◽  
R. L. Mullen ◽  
D. C. Rizos
Keyword(s):  
Particle Interaction ◽  
Time Integration ◽  
Discrete Element ◽  
Critical Discussion ◽  
Implicit Time ◽  
Integration Scheme ◽  
Computationally Efficient ◽  
Time Step ◽  
Central Difference ◽  
Time Integration Scheme

This paper presents the development of a semi-implicit time integration scheme, originally developed for structural dynamics in the 1970’s, and its implementation for use in Discrete Element Methods (DEM) for rigid particle interaction, and interaction of elastic bodies that are modeled as a cluster of rigid interconnected particles. The method is developed in view of ballast modeling that accounts for the flexibility of aggregates and the arbitrary shape and size of granules. The proposed scheme does not require any matrix inversions and is expressed in an incremental form making it appropriate for non-linear problems. The proposed method focuses on improving the efficiency, stability and accuracy of the solutions, as compared to current practice. A critical discussion of the findings of the studies is presented. Extended verification and assessment studies demonstrate that the proposed algorithm is unconditionally stable and accurate even for large time step sizes. It is demonstrated that the proposed method is at least as computationally efficient as the Central Difference Method. Guidelines for the implementation of the method to ballast modeling are discussed.

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