801 research outputs found
Modelling of Dynamic Crack Propagation in 3D Elastic Continuum Using Configurational Mechanics
This paper presents the theoretical basis and numerical implementation for simulating dynamic crack propagation in 3D hyperelastic contina within the context of configurational mechanics. The approach taken is
based on the principle of global maximum energy dissipation for elastic solids, with configurational forces determining the direction of crack propagation. The work builds on the developments made by the authors for static analysis [1], incorporating the influence of the kinetic energy. The nonlinear system of equations are solved in a monolithic manner using Newton-Raphson scheme. Initial numerical results are presented
A micromechanics-enhanced finite element formulation for modelling heterogeneous materials
In the analysis of composite materials with heterogeneous microstructures,
full resolution of the heterogeneities using classical numerical approaches can
be computationally prohibitive. This paper presents a micromechanics-enhanced
finite element formulation that accurately captures the mechanical behaviour of
heterogeneous materials in a computationally efficient manner. The strategy
exploits analytical solutions derived by Eshelby for ellipsoidal inclusions in
order to determine the mechanical perturbation fields as a result of the
underlying heterogeneities. Approximation functions for these perturbation
fields are then incorporated into a finite element formulation to augment those
of the macroscopic fields. A significant feature of this approach is that the
finite element mesh does not explicitly resolve the heterogeneities and that no
additional degrees of freedom are introduced. In this paper, hybrid-Trefftz
stress finite elements are utilised and performance of the proposed formulation
is demonstrated with numerical examples. The method is restricted here to
elastic particulate composites with ellipsoidal inclusions but it has been
designed to be extensible to a wider class of materials comprising arbitrary
shaped inclusions.Comment: 28 pages, 12 figures, 2 table
Anderson lattice with explicit Kondo coupling: general features and the field-induced suppression of heavy-fermion state in ferromagnetic phase
We apply the extended (statistically-consistent, SGA) Gutzwiller-type
approach to the periodic Anderson model (PAM) in an applied magnetic field and
in the strong correlation limit. The finite-U corrections are included
systematically by transforming PAM into the form with Kondo-type interaction
and residual hybridization, appearing both at the same time. This effective
Hamiltonian represents the essence of \textit{Anderson-Kondo lattice model}. We
show that in ferromagnetic phases the low-energy single-particle states are
strongly affected by the presence of the applied magnetic field. We also find
that for large values of hybridization strength the system enters the so-called
\textit{locked heavy fermion state}. In this state the chemical potential lies
in the majority-spin hybridization gap and as a consequence, the system
evolution is insensitive to further increase of the applied field. However, for
a sufficiently strong magnetic field, the system transforms from the locked
state to the fully spin-polarized phase. This is accompanied by a metamagnetic
transition, as well as by drastic reduction of the effective mass of
quasiparticles. In particular, we observe a reduction of effective mass
enhancement in the majority-spin subband by as much as 20% in the fully
polarized state. The findings are consistent with experimental results for
CeLaB compounds. The mass enhancement for the spin-minority
electrons may also diminish with the increasing field, unlike for the
quasiparticles states in a single narrow band in the same limit of strong
correlations
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