Browsing by Subject "Contact homogenization"

Now showing 1 - 3 of 3

Open Access
Computational homogenization of soft matter friction: Isogeometric framework and elastic boundary layers
(John Wiley and Sons Ltd, 2014) Temizer, I.
SUMMARY: A computational contact homogenization framework is established for the modeling and simulation of soft matter friction. The main challenges toward the realization of the framework are (1) the establishment of a frictional contact algorithm that displays an optimal combination of accuracy, efficiency, and robustness and plays a central role in (2) the construction of a micromechanical contact test within which samples of arbitrary size may be embedded and which is not restricted to a single deformable body. The former challenge is addressed through the extension of mixed variational formulations of contact mechanics to a mortar-based isogeometric setting where the augmented Lagrangian approach serves as the constraint enforcement method. The latter challenge is addressed through the concept of periodic embedding, with which a periodically replicated C1-continuous interface topography is realized across which not only pending but also ensuing contact among simulation cells will be automatically captured. Two-dimensional and three-dimensional investigations with unilateral/bilateral periodic/random roughness on two elastic micromechanical samples demonstrate the overall framework and the nature of the macroscopic frictional response. © 2014 John Wiley & Sons, Ltd.
Open Access
Granular contact interfaces with non-circular particles
(Elsevier, 2013) Temizer, I.
The influence of particle geometry on the macroscopic frictional response of granular interfaces is investigated via computational contact homogenization. The particle shape is parametrized by convex superellipse geometries that require iterative closest-point projection schemes for modeling the persistent rolling contact of the particle between a rigid smooth surface and a rubber-like material. Normal and tangential forces acting on the particle are computed by the discrete element method. The non-Amontons and non-Coulomb type macroscopic frictional response of the three-body system is linked to microscopic dissipative mechanisms. Numerical investigations demonstrate rolling resistance and additionally suggest that the macroscopic friction from a complex interface particle geometry may be bound by computations that are based on simplified shapes which geometrically bound the original one. © 2013 Elsevier Ltd.
Open Access
Sliding friction across the scales: Thermomechanical interactions and dissipation partitioning
(Elsevier Ltd, 2016) Temizer, İ.
A homogenization framework is developed for determining the complete macroscopic thermomechanical sliding contact response of soft interfaces with microscopic roughness. To this end, a micro-macro mechanical dissipation equality is first established which enables defining a macroscopic frictional traction. The derivation allows both contacting bodies to be deformable, thereby extending the commonly adopted setting where one of the bodies is rigid. Moreover, it forms a basis for the second step, where a novel micro-macro thermal dissipation equality is established which enables defining partitioning coefficients that are associated with the frictional dissipation as it is perceived on the macroscale. Finally, a comparison of the temperature fields from the original heterogeneous thermomechanical contact problem and an idealized homogeneous one reveals an identification of the macroscopic temperature jump. The computational implementation of the framework is carried out within an incrementally two-phase micromechanical test which delivers a well-defined macroscopic response that is not influenced by purely algorithmic choices such as the duration of sliding. Two-dimensional numerical investigations on periodic and random samples from thermo-viscoelastic boundary layers with unilateral and bilateral roughness demonstrate the temperature-velocity-pressure dependence of the macroscopic contact response. © 2016 Elsevier Ltd. All rights reserved.