Martin Ostoja-Starzewski

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The mechanisms underlying blunt head trauma are not fully understood. We developed a computational model to study the transient mechanics during head trauma events. Through frontal and side impact simulations, we discovered that the pressure input to the head gives rise not only to a fast pressure wave but also to a slow, and potentially more damaging,(More)
This review presents the potential that lattice ~or spring network! models hold for micromechanics applications. The models have their origin in the atomistic representations of matter on one hand, and in the truss-type systems in engineering on the other. The paper evolves by first giving a rather detailed presentation of one-dimensional and planar lattice(More)
Practically all elastic single crystals are anisotropic, which calls for an appropriate universal measure to quantify the extent of anisotropy. A review of the existing anisotropy measures in the literature leads to a conclusion that they lack universality in the sense that they are non-unique and ignore contributions from the bulk part of the elastic(More)
This paper series adopts particle modeling (PM) to simulation of dynamic fracture phenomena in homogeneous and heterogeneous materials, such as encountered in comminution processes in the mining industry. This first paper is concerned with the setup of a lattice-type particle model having the same functional form as the molecular dynamics (MD) model (i.e.,(More)
Currently used excavators and other construction machines use volume or high precision projects requires e x t e n hydraulic actuators as the means of providing the necessary sive~ preparatory work or elaborate safety precaupower to their effector tooling. The tools lack the flexibility of tions before the task execution is commenced. applying varying(More)
This paper focuses on the ultrastructure of bone at a single lamella level. At this scale, collagen fibrils reinforced with apatite crystals are aligned preferentially to form a lamella. At the next structural level, such lamella are stacked in different orientations to form either osteons in cortical bone or trabecular pockets in trabecular bone. We use a(More)
We consider the constitutive law of paper and its relation to a spatially inhomogeneous, random paper structure, the so-called formation. Under biaxial tensile loading, paper may be taken as an elastic-plastic hardening material, modelled here by a hyperbolic tangent law. The fact that paper is a quasi-two-dimensional solid offers a chance to inspect its(More)
When an electric field is applied to an electrolyte-saturated polymer gel embedded with charged colloidal particles, the force that must be exerted by the hydrogel on each particle reflects a delicate balance of electrical, hydrodynamic, and elastic stresses. This paper examines the displacement of a single charged spherical inclusion embedded in an(More)
The results established in contemporary statistical physics indicating that, on very small space and time scales, the entropy production rate may be negative, motivate a generalization of continuum mechanics. On account of the fluctuation theorem, it is recognized that the evolution of entropy at a material point is stochastically (not deterministically)(More)