Publications (19)
Symmetric unisolvent equations for linear elasticity purely in stresses
Adam Sky, Andreas Zilian
In this work we introduce novel stress-only formulations of linear elasticity with special attention to their approximate solution using weighted residual methods. We present four…
A Reissner-Mindlin plate formulation using symmetric Hu-Zhang elements via polytopal transformations
Adam Sky, Michael Neunteufel, Jack S. Hale +1
In this work we develop new finite element discretisations of the shear-deformable Reissner--Mindlin plate problem based on the Hellinger-Reissner principle of symmetric stresses.…
Green's functions for the isotropic planar relaxed micromorphic model -- concentrated force and concentrated couple
Panos Gourgiotis, Gianluca Rizzi, Peter Lewintan +4
We derive the Green's functions (concentrated force and couple in an infinite space) for the isotropic planar relaxed micromorphic model. Since the relaxed micromorphic model parti…
Primal and mixed finite element formulations for the relaxed micromorphic model
Adam Sky, Michael Neunteufel, Ingo Muench +2
The classical Cauchy continuum theory is suitable to model highly homogeneous materials. However, many materials, such as porous media or metamaterials, exhibit a pronounced micros…
A constitutive condition for idealized isotropic Cauchy elasticity involving the logarithmic strain
Marco Valerio d'Agostino, Sebastian Holthausen, Davide Bernardini +4
Following Hill and Leblond, the aim of our work is to show, for isotropic nonlinear elasticity, a relation between the corotational Zaremba-Jaumann objective derivative of the Cauc…
Yet another best approximation isotropic elasticity tensor in plane strain
Jendrik Voss, Panos Gourgiotis, Peter Lewintan +2
For plane strain linear elasticity, given any anisotropic elasticity tensor , we determine a best approximating isotropic counterpart …
Polytopal templates for the formulation of semi-continuous vectorial finite elements of arbitrary order
Adam Sky, Ingo Muench
The Hilbert spaces and are needed for variational problems formulated in the context of the de Rham complex in order to guarantee well-posednes…
A structure-preserving discretisation of SO(3)-rotation fields for finite Cosserat micropolar elasticity
Lucca Schek, Peter Lewintan, Wolfgang Müller +5
We introduce a new method, dubbed Geometric Structure-Preserving Interpolation (-SPIN) to preserve physics-constraints inherent in the material parameter limits of the finite-s…
Hypo-elasticity, Cauchy-elasticity, corotational stability and monotonicity in the logarithmic strain
Patrizio Neff, Sebastian Holthausen, Marco Valerio d'Agostino +4
We combine the rate-formulation for the objective, corotational Zaremba-Jaumann rate \begin{align} \frac{{\rm D}^{\rm ZJ}}{{\rm D} t} [Ï] = \mathbb{H}^{\rm ZJ}(Ï).D, \qquad D = {…
Formulae and transformations for simplicial tensorial finite elements via polytopal templates
Adam Sky, Michael Neunteufel, Jack S. Hale +1
We introduce a unified method for constructing the basis functions of a wide variety of partially continuous tensor-valued finite elements on simplices using polytopal templates. T…
Higher order Bernstein-Bézier and Nédélec finite elements for the relaxed micromorphic model
Adam Sky, Ingo Muench, Gianluca Rizzi +1
The relaxed micromorphic model is a generalized continuum model that is well-posed in the space . Consequently, finite element formulations…
On H1, H(curl) and H(sym Curl) finite elements for matrix-valued Curl problems
Adam Sky, Ingo Muench, Patrizio Neff
In this work we test the numerical behaviour of matrix-valued fields approximated by finite element subspaces of , and $…
A hybrid H1xH(curl) finite element formulation for a relaxed micromorphic continuum model of antiplane shear
Adam Sky, Michael Neunteufel, Ingo Münch +2
One approach for the simulation of metamaterials is to extend an associated continuum theory concerning its kinematic equations, and the relaxed micromorphic continuum represents s…
Intrinsic mixed-dimensional beam-shell-solid couplings in linear Cosserat continua via tangential differential calculus
Adam Sky, Jack S. Hale, Andreas Zilian +2
We present an approach to the coupling of mixed-dimensional continua by employing the mathematically enriched linear Cosserat micropolar model. The kinematical reduction of the mod…
An essay on deformation measures in isotropic thin shell theories. Bending versus curvature
Ionel-Dumitrel Ghiba, Peter Lewintan, Adam Sky +1
It has become commonplace for the stored energy function of any realistic shell model to align ``within first order" with the classical Koiter membrane-bending (flexural) shell mod…
Novel -conforming elements on regular triangulations and Clough--Tocher splits for the planar relaxed micromorphic model
Adam Sky, Michael Neunteufel, Peter Lewintan +3
In this work we present a consistent reduction of the relaxed micromorphic model to its corresponding two-dimensional planar model, such that its capacity to capture discontinuous…
Novel -conforming finite elements for the relaxed micromorphic sequence
Adam Sky, Michael Neunteufel, Peter Lewintan +2
In this work we construct novel -conforming finite elements for the recently introduced relaxed micromorphic sequence, which can be considered as the…
A flexible sparse matrix data format and parallel algorithms for the assembly of sparse matrices in general finite element applications using atomic synchronisation primitives
Adam Sky, César Polindara, Ingo Muench +1
Finite element methods require the composition of the global stiffness matrix from local finite element contributions. The composition process combines the computation of element s…
Cosserat micropolar and couple-stress elasticity models of flexomagnetism at finite deformations
Adam Sky, David Codony, Stephan Rudykh +3
We propose geometrically nonlinear (finite) continuum models of flexomagnetism based on the Cosserat micropolar and its descendent couple-stress theory. These models introduce the…