Showing 2 results for Soil-Structure Interaction
N.a. Hosseinzadeh, F. Nateghi-Alahi and F. Behnamfar,
Volume 22, Issue 2 (1-2004)
Abstract
The objective of this study is to design a robust direct model reference adaptive controller (DMRAC) for a nonlinear cardiovascular model over a range of plant parameters representing a variety of physical conditions. The direct adaptive controllers used in thisd study require the plant to be almost strictly positive real (ASPR) that is, for a plant to be controlled there must exist a feedback gain such that the resulting closed loop system is strictly positive real. We designed a new compensator so that the system composed of the cardiovascular plant and the compensator satisfy the ASPR condition.
Numerous studies in the past have considered a small range of gain variations of the cardiovascular system. In most cases, the controller was designed based on variations in either time delay or plant gains. Many of these workers treated the cardiovascular system as a single-input single output (SISo) plant in which the control output was Mean Arterial Pressure (MAO). We treated the cardiovascular system as a multi-input multi-output (MIMO) plant in which both the MAP and Cardiac Output (CO) are simultaneously controlled.
In this study, a new linear model is presented that provides a better approximation thanthe one the original linear model does. By doing so and utilizing the DMRAC algorithm, we could satisfy the stability conditions for the nonlinear model while satisfactory responses obtained under every possible condition for the cardiovascular nonlinear model.
S. Roushanbin, M.r. Maheri and A Rangbaran,
Volume 24, Issue 1 (7-2005)
Abstract
There are a number of parameters influencing the dynamic and seismic response of bridges. Of these, two important parameters warranting special notice include: the properties of the neoperenes in the state of connection between girders and columns and the shear stiffness of underlying soil in the level of bridge substructure’s connectivity to the ground. In
this paper, the effects of these two parameters on the dynamic and seismic response of Ghadir Bridge in Isfahan are investigated. The main conclusions drawn from these investigations include: the sensitivity of the bridge’s lateral modes of vibration to the horizontal shear stiffness of the neoperenes and the substantial effects of the soil’s shear rigidity on the longitudinal modes. Based on the findings, it is recommended tha a thorough geotechnical site investigation of the soil be conducted and the properties of the underlying soil be accurately established in order to correctly identify the dynamic behaviour of a bridge.
