Determination of Structural‐System Transfer Functions by Time Correlation

1962 ◽  
Vol 34 (12) ◽  
pp. 1983-1983
Author(s):  
Stanley G. Champ
Keyword(s):  
Transfer Functions ◽  
Time Correlation ◽  
Structural System

Error analyses of a Multi-Input-Multi-Output cantilever beam test

2021 ◽  
pp. 107754632110337
Author(s):  
Arup Maji ◽  
Fernando Moreu ◽  
James Woodall ◽  
Maimuna Hossain
Keyword(s):  
Transfer Function ◽  
Frequency Domain ◽  
Cantilever Beam ◽  
Transfer Functions ◽  
Linear Superposition ◽  
Transfer Function Matrix ◽  
Error Analyses ◽  
Pseudo Inverse ◽  
Function Matrix

Multi-Input-Multi-Output vibration testing typically requires the determination of inputs to achieve desired response at multiple locations. First, the responses due to each input are quantified in terms of complex transfer functions in the frequency domain. In this study, two Inputs and five Responses were used leading to a 5 × 2 transfer function matrix. Inputs corresponding to the desired Responses are then computed by inversion of the rectangular matrix using Pseudo-Inverse techniques that involve least-squared solutions. It is important to understand and quantify the various sources of errors in this process toward improved implementation of Multi-Input-Multi-Output testing. In this article, tests on a cantilever beam with two actuators (input controlled smart shakers) were used as Inputs while acceleration Responses were measured at five locations including the two input locations. Variation among tests was quantified including its impact on transfer functions across the relevant frequency domain. Accuracy of linear superposition of the influence of two actuators was quantified to investigate the influence of relative phase information. Finally, the accuracy of the Multi-Input-Multi-Output inversion process was investigated while varying the number of Responses from 2 (square transfer function matrix) to 5 (full-rectangular transfer function matrix). Results were examined in the context of the resonances and anti-resonances of the system as well as the ability of the actuators to provide actuation energy across the domain. Improved understanding of the sources of uncertainty from this study can be used for more complex Multi-Input-Multi-Output experiments.

scholarly journals DETERMINATION OF POWER LINE TRANSFER FUNCTIONS BY A METHOD OF IMPEDANCE TRANSFER AND VOLTAGE SPREAD

2018 ◽  
Vol 71 ◽  
pp. 63-74 ◽  
Author(s):  
Thanakorn Khongdeach ◽  
Wachira Chongburee ◽  
Nattaka Homsup
Keyword(s):  
Transfer Functions ◽  
Power Line ◽  
Line Transfer

scholarly journals Comparação entre a eficiência estrutural de perfis soldados de aço e perfis de aço formados a frio

2016 ◽  
Vol 12 (3) ◽  
Author(s):  
Uiatan Aguiar Nogueira ◽  
Matilde Batista Melo ◽  
Daniel De Lima Araujo
Keyword(s):  
Bending Strength ◽  
Steel Beams ◽  
Steel Beam ◽  
Structural Elements ◽  
Structural System ◽  
Welded Steel ◽  
Bending Tests ◽  
Structural Efficiency ◽  
Cold Formed Steel

RESUMO: A Análise de elementos estruturais, realizadas durante as etapas de projeto de uma estrutura, é parte fundamental para garantia de bom desempenho e estabilidade do sistema estrutural. Na execução de algumas estruturas, como as coberturas em edificações, é usual o emprego de perfis leves de aço formados a frio devido ao seu baixo peso. Esta pesquisa tem por objetivo avaliar a eficiência estrutural desses perfis quando comparados, por exemplo, aos perfis soldados compactos. Para tanto, foram realizados ensaios de flexão em quatro vigas biapoiadas submetidas a duas forças concentradas, de forma a se obter flexão pura no meio do vão das vigas. Estas foram instrumentadas para a determinação da sua rigidez e da sua resistência à flexão. A principal contribuição deste trabalho é demonstrar a eficiência estrutural de perfis formados a frio em seção caixa submetidos à flexão em comparação com perfis de seção tipo “H” soldados. ABSTRACT: The analysis of structural elements, in a structure’s design, is an essential step to ensure good performance and stability of the structural system. In any types of structures, such as roofing in buildings, it’s usual using cold-formed steel beams due to their small weight. This research seeks to evaluate the structural efficiency of cold-formed steel beams when compared, for example, to compact welded steel beams. Thus, bending tests were performed in four simply supported beams submitted to two concentrated loads, in order to obtain pure flexure at the mid-span of the beams. These beams were instrumented for the determination of their rigidity and bending strength. The results showed that the cold-formed steel beam, box-shaped, presented structural efficiency similar to the welded steel beam “H” shaped.

scholarly journals Evolution Regularity Mining and Gating Control Method of Urban Recurrent Traffic Congestion: A Literature Review

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Changxi Ma ◽  
Jibiao Zhou ◽  
Xuecai (Daniel) Xu ◽  
Jin Xu
Keyword(s):  
Traffic Congestion ◽  
Quantitative Research ◽  
Control Method ◽  
Time Correlation ◽  
Small Scale ◽  
Trend Prediction ◽  
Quantitative Research Methods ◽  
The Status ◽  
Evolution Trend

To understand the status quo of urban recurrent traffic congestion, the current results of recurrent traffic congestion, and gating control are reviewed from three aspects: traffic congestion identification, evolution trend prediction, and urban road network gating control. Three aspects of current research are highlighted: (a) The majority of current studies are based on statistical analyses of historical data, while congestion identification is performed by acquiring small-scale traffic parameters. Thus, congestion studies on the urban global roadway network are lacking. Situation identification and the failure to effectively warn or even avoid traffic congestion before congestion forms are not addressed; (b) correlation studies on urban roadway network congestion are inadequate, especially regarding deep learning, and considering the space-time correlation for congestion evolution trend prediction; and (c) quantitative research methods, dynamic determination of gating control areas, and effective countermeasures to eliminate traffic congestion are lacking. Regarding the shortcomings of current studies, six research directions that can be further explored in the future are presented.

Making IoT Run

2017 ◽  
Vol 1 (2) ◽  
pp. 26-44
Author(s):  
Peter Schott ◽  
Torben Schaft ◽  
Stefan Thomas ◽  
Freimut Bodendorf
Keyword(s):  
Production Systems ◽  
Smart Manufacturing ◽  
Structural System ◽  
Maturity Level ◽  
Smart Systems ◽  
Industrial Iot ◽  
Increasing Demand ◽  
Manufacturing Environments ◽  
Self Learning

This article describes how today's manufacturing environments are characterized by an increasing demand for individual products and constantly more product variants. Concomitant, developments in the fields of IT, robotics and artificial intelligence allow the realization of smart systems, which means networked, self-learning, self-regulating and versatile production systems to control this complexity. These developments are referred to as industrial IoT that is acknowledged as “next big thing” in production. Firms face the challenge of lacking guidelines for implementing IoT solutions. Neither the technological prerequisites nor generally applicable procedures for realizing an appropriate technological maturity level of the system-to-be exist. Addressing this deficit, a framework is introduced which systematically implements IoT within manufacturing. The framework presents a guideline for the establishment of structural system understanding, the determination of the target system's technological maturity level from a customer's perspective and, building on this, design implications for smart manufacturing.

An Approac e Determination of Aircraft Handling Qualities Using Pilot Transfer Functions

1971 ◽  
Vol 8 (5) ◽  
pp. 319-324
Author(s):  
JAMES J. ADAMS ◽  
HOWARD B. HATCH
Keyword(s):  
Transfer Functions ◽  
Handling Qualities

Experimental Determination of Water Motions Inside a Moonpool

2017 ◽  
Author(s):  
Bastien Abeil
Keyword(s):  
Experimental Determination ◽  
Transfer Functions ◽  
Side Wall ◽  
Model Tests ◽  
Irregular Waves ◽  
Video Recordings ◽  
Non Linear ◽  
Relative Water ◽  
Water Elevation

Model tests of a drillship with a rectangular moonpool opening were conducted in regular and irregular waves from the bow and bow-quarter. Most tests were conducted at zero speed, the rest was performed with the model towed to a speed of 10 kn. From the video-recordings and transfer functions of the measured relative water elevation inside the moonpool, the typical piston and first sloshing modes are well captured, for wave frequencies that agree relatively well with relevant formulations. A few tests conducted at varying wave amplitudes show that the water elevation is non-linear by nature, while repeat tests conducted with the moonpool fitted with two layers of side wall flanges shows that these can reduce the water motions by nearly 40 %.

Sign in / Sign up

Export Citation Format

Share Document