A Stochastic Analysis for Multiple Supported MDOF Secondary Systems

1995 ◽  
Vol 117 (2) ◽  
pp. 182-188 ◽  
Author(s):  
A. Saudy ◽  
T. Aziz ◽  
A. Ghobarah
Keyword(s):  
Dynamic Loading ◽  
Stochastic Analysis ◽  
Dynamic Interaction ◽  
Primary System ◽  
Secondary System ◽  
Theoretical Formulation ◽  
Interaction Forces ◽  
Numerical Examples ◽  
Secondary Systems ◽  
System Properties

A new stochastic analysis is developed to estimate the response of multiple supported mdof secondary systems to dynamic loading. In the proposed stochastic analysis, the effect of the dynamic interaction between the secondary and primary systems is included. An outline for the theoretical formulation of the proposed stochastic analysis is presented. The assumptions adopted in the formulation are discussed. The dynamic interaction is shown to comprise two effects: the effect of the interaction forces arising at the attachment points, and the effect of the changes in the primary system properties resulting from the attachment of the secondary system. In addition, numerical examples are provided to demonstrate the validity of the proposed analysis.

scholarly journals Seismic Forces in Ancillary Components Supported on Piers and Wharves

2018 ◽  
Vol 34 (2) ◽  
pp. 741-758 ◽  
Author(s):  
Rakesh K. Goel
Keyword(s):  
Simple Procedure ◽  
Single Mode ◽  
Primary System ◽  
Elastic Model ◽  
Secondary System ◽  
Marine Structures ◽  
Acceleration Amplification ◽  
Marine Structure ◽  
Secondary Systems ◽  
Seismic Forces

This paper presents a simple procedure to estimate seismic forces in ancillary components (secondary systems) supported on marine structures such as piers, wharves, and marine oil terminals (primary systems). Since many such marine structures can be idealized as single-degree-of-freedom (SDOF) systems, this study uses a simple linear-elastic model with two DOF, one representing the marine structure and the other representing the ancillary component. This study shows that acceleration at the base of the secondary system is approximately equal to spectral acceleration at the fundamental period of the primary system. It also proposes a formula, which is an improvement over current ASCE 7-10 recommendations, to estimate acceleration amplification in the secondary system due to its flexibility when mass and period ratios of the secondary and primary systems are known. The procedure in this paper is strictly applicable to marine structures for which primarily a single mode contributes to seismic response.

On the Nonstationary Response of Stochastically Excited Secondary Systems

1987 ◽  
Vol 54 (3) ◽  
pp. 688-694 ◽  
Author(s):  
W. D. Iwan ◽  
K. S. Smith
Keyword(s):  
Closed Form Expression ◽  
Primary System ◽  
Mean Square ◽  
Stochastic Excitation ◽  
Secondary System ◽  
Form Expression ◽  
Combined System ◽  
Nonstationary Response ◽  
Secondary Systems ◽  
The Mean

The envelope response of a secondary system is derived for the case where the primary system is subjected to nonstationary stochastic excitation. An approximate closed form expression for the mean square envelope response is obtained for the case of transient response to stationary excitation when the primary and secondary systems are noninteracting. When the combined system is classically damped, the effect of the interaction is described by the introduction of an equivalent noninteracting system. The analytical results are compared with results of numerical simulations.

Optimal Performance Comparison of Nonlinear Energy Sinks and Linear Tuned Mass Dampers

2021 ◽  
Author(s):  
Ivan Yegorov (Egorov) ◽  
Austin Uden ◽  
Daniil Yurchenko
Keyword(s):  
Nonlinear Energy Sink ◽  
Free Vibrations ◽  
Performance Comparison ◽  
Optimal Performance ◽  
Primary System ◽  
Secondary System ◽  
Impulsive Excitation ◽  
Secondary Systems ◽  
Energy Sink ◽  
Nonlinear Energy

Abstract This paper studies a targeted energy transfer (TET) mechanism for a two-degree-of-freedom (TDOF) model in free vibration. The model comprises a primary linear system and a secondary system in the form of an energy sink which can be nonlinear. The free vibrations are considered subject to an impulsive excitation exerted on the primary system, leading to a nonzero initial velocity. The goal is to obtain the spring parameters in the nonlinear energy sink (NES) so as to maximize an energy dissipation measure (EDM) representing the percentage of impulsive energy that is absorbed and dissipated in the NES. A global optimization algorithm is used for this purpose. The optimal performance is assessed for the purely linear, linear-cubic, and purely cubic configurations of the spring connecting the primary and secondary systems. The corresponding results are compared with each other. The optimization process is performed for the EDM averaged over given ranges of the initial impulse and natural frequency in the primary system. It is shown that the type of the optimal configuration can vary depending on these ranges.

An infinite-server queue subject to an extraneous phase process and related models

1981 ◽  
Vol 18 (1) ◽  
pp. 236-244 ◽  
Author(s):  
P. Purdue ◽  
D. Linton
Keyword(s):  
Original System ◽  
Primary System ◽  
Secondary System ◽  
State Behavior ◽  
Infinite Server ◽  
Server Queue ◽  
Secondary Systems ◽  
Stage System ◽  
The Mean ◽  
Bulk Arrival

We consider an infinite-server queueing system in an extraneous environment. Initially it is shown that the systems of interest can be decomposed into a two-stage system. The primary system is an infinite-server queue with many customer types subject to a clearing mechanism. The secondary system is a special type of bulk-arrival, infinite-server queue. We derive results for the primary and secondary systems separately and combine the results to find the mean steady-state behavior of the original system.

An infinite-server queue subject to an extraneous phase process and related models

1981 ◽  
Vol 18 (01) ◽  
pp. 236-244 ◽  
Author(s):  
P. Purdue ◽  
D. Linton
Keyword(s):  
Original System ◽  
Primary System ◽  
Secondary System ◽  
State Behavior ◽  
Infinite Server ◽  
Server Queue ◽  
Secondary Systems ◽  
Stage System ◽  
The Mean ◽  
Bulk Arrival

We consider an infinite-server queueing system in an extraneous environment. Initially it is shown that the systems of interest can be decomposed into a two-stage system. The primary system is an infinite-server queue with many customer types subject to a clearing mechanism. The secondary system is a special type of bulk-arrival, infinite-server queue. We derive results for the primary and secondary systems separately and combine the results to find the mean steady-state behavior of the original system.

Stochastic Analysis of Temperature Distribution in a Solid With Random Heat Conductivity

1988 ◽  
Vol 110 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Da Yu Tzou
Keyword(s):  
Thermal Conductivity ◽  
Temperature Distribution ◽  
Heat Conductivity ◽  
Stochastic Analysis ◽  
Solid Medium ◽  
Mean Value ◽  
Random Response ◽  
Thermal Failure ◽  
Numerical Examples ◽  
The Mean

Stochastic temperature distribution in a solid medium with random heat conductivity is investigated by the method of perturbation. The intrinsic randomness of the thermal conductivity k(x) is considered to be a distribution function with random amplitude in the solid, and several typical stochastic processes are considered in the numerical examples. The formulation used in the present analysis describes a situation that the statistical orders of the random response of the system are the same as those of the intrinsic random excitations, which is characteristic for the problem with extrinsic randomness. The maximum standard deviation of the temperature distribution from the mean value in the solid medium reveals the amount of unexpected energy experienced by the solid continuum, which should be carefully inspected in the thermal-failure design of structures with intrinsic randomness.

Legendre Spectral Collocation Technique for Advection Dispersion Equations Included Riesz Fractional

2021 ◽  
Vol 6 (1) ◽  
pp. 9
Author(s):  
Mohamed M. Al-Shomrani ◽  
Mohamed A. Abdelkawy
Keyword(s):  
Numerical Methods ◽  
Numerical Algorithm ◽  
Spectral Collocation ◽  
Theoretical Formulation ◽  
Numerical Examples ◽  
Dispersion Equations ◽  
Advection Dispersion ◽  
Collocation Technique ◽  
Collocation Approach

The advection–dispersion equations have gotten a lot of theoretical attention. The difficulty in dealing with these problems stems from the fact that there is no perfect answer and that tackling them using local numerical methods is tough. The Riesz fractional advection–dispersion equations are quantitatively studied in this research. The numerical methodology is based on the collocation approach and a simple numerical algorithm. To show the technique’s performance and competency, a comprehensive theoretical formulation is provided, along with numerical examples.

Secondary Use of Radio Spectrum by High Altitude Platform

2013 ◽  
pp. 290-300
Author(s):  
Zhe Yang ◽  
Abbas Mohammed
Keyword(s):  
High Altitude ◽  
Spectrum Sharing ◽  
Radio Spectrum ◽  
Primary System ◽  
Secondary System ◽  
Secondary Use ◽  
Terrestrial System ◽  
High Altitude Platform ◽  
Radio Resources ◽  
Systems Simulation

Traditional spectrum licensing enables guaranteed quality of service but could lead to inefficient use of the spectrum. The quest to achieve higher usage efficiency for the spectrum has been the hottest research topic worldwide recently. More efficient transmission technologies are being developed, but they alone cannot solve problems of spatially and temporally underused spectrum and radio resources. In this chapter, the authors review major challenges in traditional spectrum sharing and mechanisms to optimize the efficiency of spectrum usage. They investigate and assess incentives of a primary terrestrial system and secondary system based on a High-Altitude Platform (HAP) to share spectrum towards common benefits. The primary terrestrial system is defined to have exclusive rights to access the spectrum, which is shared by the secondary HAP system upon request. The Markov chain is presented to model two spectrum-sharing scenarios and evaluate the performance of spectrum sharing between primary terrestrial and secondary HAP systems. Simulation results show that to reserve an amount of spectrum from a primary system could encourage spectrum sharing with a secondary system, which has a frequent demand on requesting spectrum resources.

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