This paper is concerned with information structures used in rigid formations of autonomous agents that have leaderfollower architecture. The focus of this paper is on sensor/network topologies to secure control of rigidity. We extend our previous approach for formations with symmetric neighbor relations to include formations with leader-follower architecture. Necessary and sufficient conditions...

We investigate the stability and geometrically nonlinear dynamics of slender rods made of a linear isotropic poroelastic material. Dimensional reduction leads to the evolution equation for the shape of the poroelastica where, in addition to the usual terms for the bending of an elastic rod, we find a term that arises from fluid–solid interaction. Using the poroelastica equation as a starting po...

Formations of multi-agent systems, such as satellites and aircraft, require that individual agents satisfy their kinematic equations while constantly maintaining inter-agent constraints. In this paper, we develop a systematic framework for studying formations of multiagent systems. In particular, we consider undirected formations for centralized formations and directed formations for decentrali...

Motivated by recent experimental studies, we derive and analyze a two-dimensional model for the contraction patterns observed in protoplasmic droplets of Physarum polycephalum. The model couples a description of an active poroelastic two-phase medium with equations describing the spatiotemporal dynamics of the intracellular free calcium concentration. The poroelastic medium is assumed to consis...

The standard model of injection-induced seismicity considers changes in Coulomb strength due solely to changes in pore pressure. We consider two additional effects: full poroelastic coupling of stress and pore pressure, and time-dependent earthquake nucleation. We model stress and pore pressure due to specified injection rate in a homogeneous, poroelastic medium. Stress and pore pressure are us...

Efficient and accurate hydrothermal and mechanical mathematical models in porous media constitute a fundamental tool for improving the understanding of the subsurface dynamics in volcanic areas. We propose a finite-difference ghost-point method for the numerical solution of thermo-poroelastic and gravity change equations. The main aim of this work is to study how the thermo-poroelastic solution...

The isolation of the vibration due to a harmonic vertical load using pile rows embedded in a saturated poroelastic half-space is investigated in this study. Using the fundamental solution for a circular patch load and Muki’s method, the second kind of Fredholm integral equations describing the dynamical interaction between the pile rows and the saturated poroelastic half-space are obtained. Num...

Porous materials have recently been used in absorptive treatments around railway tracks to reduce noise emissions. To investigate the effect of porous materials, a finite element model has been developed. 2D models for porous materials have been considered either as an equivalent fluid or as a poroelastic material based on the Biot theory. The two models have been validated and compared with ea...

SUMMARY Behavior of a poroelastic material bonded onto a vibrating plate is investigated in the low frequency range. From the analysis of dissipation mechanisms, a model accounting for damping added by the porous layer on the plate is derived. This analysis is based on a 3-D finite element formulation including poroelastic elements based on Biot displacement theory. First, dissipated powers rel...

We examine a spherically symmetric model of the brain and apply non-linear permeability in a small strain poroelastic framework. Numerical solutions to the model show that non-linear effects tend to improve predictions of ventricle wall displacement and pressure increase in acute hydrocephalus in comparison with a constant permeability model. Our model is used to study different mechanisms for ...