Bifurcations and Chaos in Structural Control
We study a harmonically forced oscillator with nonlinear soft spring subjected to a linear feedback control with time delay. This system can be written as a three dimensional dynamical...
Regularization Methods for Identification of Structural Damage
Generally, various non-unique solutions may be obtained from ill-conditioned equations. Several methods are available to obtain a unique (minimum energy) solution to a modified and thus...
Updating Dynamic Models and Their Associated Uncertainties for Structural Systems
The problem of updating a structural model and its associated uncertainties using dynamic test data is addressed, considering uncertainties which arise from measurement noise, modeling...
Applications of Viscoelastic Damper to Jointed Structures for Seismic Mitigation
Some structures, such as dams, are built with contraction joints that might carry some small tensile stresses. Such joints are expected to open and close during an earthquake. That will...
Anatomy of the Loma Prieta Earthquake Records of Two Steel Buildings Using MIMO System Identification
The Loma Prieta strong-motion records of a 4-story and a 47-story steel building are analyzed using system identification. A time variation study from the 4-story building records reveals...
Effect of Active Control on Closely Spaced Natural Frequencies
Current problems in structural control involve structures with closely spaced natural frequencies (M.J. Balas, 1983). The purpose of this paper is to show how control affects a structure...
A Hydraulic Study of Venous Valve Closure
The functions of the veins is to convey blood from the periphery to the heart. The distribution and transportation of blood between different parts of the body is regulated by a host of...
Seismic Stability Analysis of Landfill
The failure mechanism of a waste containment system is not well understood due to the complexity and the heterogeneity of the system. The recent slope failure of the Kettleman Hills waste...
Mathematical Characterization of Fabric and Its Use in Mechanics of Geomaterials
Increased evidence of the influence of their discrete nature on the observed behavior of geomaterials has prompted a number of investigators to look at these materials at the microstructural...
Constitutive Equation for Granular Material by Hypoelasticity
Constitutive equations for soil based upon the incremental theory of hypoelasticity are proposed in this paper to account for the stress path dependency and dilatant behavior of soil....
The Microstructure of Hardened Cement Paste and Concrete
Concrete is a composite material created from a mixture of a binder (hardened portland cement paste) and a filler (fine and coarse aggregates). Like any other composite material the physical...
Micromechanics Based Design for Pseudo Strain-Hardening in Cementitious Composites
Micromechanical model constructed on the basis of fracture mechanics and fiber bridging provides a means of selection of fiber, matrix and interface property combinations for which short...
Effect of Micro-parameters on the Macroscopic Behaviour of Ductile Fiber Reinforced Brittle Matrix Composites
In this paper, the modelling of crack bridging stress vs crack opening (?-?) relation of ductile fiber brittle matrix composite in terms of its microscopic parameters is described. Parametric...
The Morphology and Dynamics of Natural and Laboratory Grain Flows
Artificially generated sand flows that display considerable similarity with field examples on eolian dunes allow documentation of the relationships between grainflow scales and the characteristics...
Computer Simulation of Granular Flows
Discrete-particle computer simulations using up to 15,000 identical spheres reproduce particle-scale information obtained from high-speed motion picture observations of disperse, collision-dominated...
Discrete Mechanics of Sediment Transport
Usually a granular medium is being represented by a continuous approximation in which the degrees of freedom of individual grains are averaged away in favor of a partial differential equation...
Computer Simulation of Dry Layered Granular Flow Down an Incline Composed of Grains
Experiments show that gravity-driven dry granular flows are essentially layered for smooth spheres. This paper describes layer-to-layer interaction in the flow. Assuming two-dimensional...
A Sphere Moving Down an Inclined Bumpy Surface
A sphere moving down a bumpy incline in the air is studied theoretically and experimentally. A method based on the principle of energy conservation is used to express the average velocity...
Distributed Failure Analysis, Fallacies and Remedies
In the past, two distinctly different approaches - smeared and discrete failure descriptions have been utilised to capture failure mechanisms in solids and structures. These two approaches...
Computational Gradient Plasticity
The inclusion of higher-order deformation gradients is of paramount importance for properly describing strain localization within the framework of continuum mechanics. In this contribution...
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