Dynamic testing of an open web steel joist floor

1981 ◽  
Vol 8 (2) ◽  
pp. 257-262
Author(s):  
M. Y. T. Chan ◽  
M. S. Cheung
Keyword(s):  
Dynamic Characteristics ◽  
Magnetic Tape ◽  
Dynamic Testing ◽  
Spectrum Analyzer ◽  
Maximum Strain ◽  
Operational Conditions ◽  
Strip Chart ◽  
Dual Channel ◽  
Recorded Data ◽  
Open Web Steel Joist

A non-composite open web steel joist warehouse floor was tested to determine its dynamic characteristics and maximum strain levels under actual operational conditions. Altogether 28 tests were carried out. The strain and acceleration information for each test was recorded on strip chart and magnetic tape recorders. The recorded data were examined and analyzed through a dual channel spectrum analyzer and the results were compared with calculated values. Good agreements are noted.

INFLUENCE OF GAS-DYNAMIC TESTING RIG PIPELINES MATERIAL ON THEIR DYNAMIC CHARACTERISTICS

2021 ◽  
pp. 118-125
Author(s):  
А.В. Саврико ◽  
С.Н. Лымич ◽  
К.В. Кружаев ◽  
В.С. Левин ◽  
А.В. Москвичев
Keyword(s):  
Flow Rate ◽  
Dynamic Characteristics ◽  
Dynamic Testing ◽  
Analytical Calculation ◽  
Working Fluid ◽  
Factors Affecting ◽  
Pressure Losses ◽  
Steel Pipes ◽  
Gas Dynamic ◽  
Friction Pressure

Приведено исследование зависимости газодинамических характеристик стенда от применяемого материала трубопровода. Oсновополагающими факторами, влияющими на работоспособность стенда, являются выходные параметры - давление и расход рабочего тела, которые напрямую зависят от потерь давления на трение, создаваемого элементами стенда. Для оценки степени влияния материалов на потери стенда выбраны два вида труб: полипропиленовые и металлические. Аналитические расчёты потери давления рассматриваемых трубопроводов из различного материала показали, что трубопроводы из полипропилена предпочтительнее. Однако при проведении эксперимента получены противоположные данные, которые показали, что в полипропиленовых магистралях возможно присутствие значительного количества диафрагм: в местах пайки труб, образовавшихся в процессе изготовления. Именно этот факт способствует существенному повышению значений сопротивлений в полипропиленовых трубопроводах на 20 % по сравнению со стальными трубами, где диафрагмы отсутствуют. В результате проведения исследования был введен коэффициент, учитывающий влияние диафрагм полипропиленового трубопровода при аналитическом расчете на сопротивление. Для сохранения более точных снимаемых значений с газодинамических стендов целесообразнее использовать трубопроводы из металла, в которых рассчитать потери возможно с отклонениями до 3 % Here we give the study of the dependence of the gas-dynamic characteristics of the stand on the pipeline material used. The fundamental factors affecting the performance of the stand are the output parameters-the pressure and flow rate of the working fluid, which directly depend on the friction pressure losses created by the elements of the stand. To assess the degree of influence of materials on the losses of the stand, we selected two types of pipes: polypropylene and metal. Analytical calculations of the pressure loss of the considered pipelines made of various materials have shown that pipelines made of polypropylene are preferable. However, during the experiment, we obtained the opposite data, which showed that a significant number of diaphragms may be present in polypropylene pipelines: in the places of soldering of pipes formed during the manufacturing process. This fact contributes to a significant increase in the resistance values in polypropylene pipelines by 20 % compared to steel pipes, where there are no diaphragms. As a result of the study, we introduced a coefficient that takes into account the influence of polypropylene pipeline diaphragms in the analytical calculation of resistance. To preserve more accurate values taken from gas-dynamic stands, it is more expedient to use metal pipelines in which it is possible to calculate losses with deviations of up to 3 %

scholarly journals Multichannel Inductive Sensor Based on Phase Division Multiplexing for Wear Debris Detection

Micromachines ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 246 ◽  
Author(s):  
Sen Wu ◽  
Zhijian Liu ◽  
Haichao Yuan ◽  
Kezhen Yu ◽  
Yuefeng Gao ◽  
...  
Keyword(s):  
Real Time ◽  
Wear Debris ◽  
Dynamic Testing ◽  
High Sensitivity ◽  
Time Machine ◽  
Synchronized Sampling ◽  
Sensing System ◽  
Lubricant Oil ◽  
Recorded Data ◽  
Multiple Sensing

Inductive wear debris sensor has been widely used in real time machine lubricant oil condition monitoring and fault forecasting. However, the small sensing zone, which is designed for high sensitivity, of the existing sensors leads to low throughput. In order to improve the throughput, a novel multichannel wear debris sensor that is based on phase division multiplexing is presented. By introducing the phase shift circuit into the system, multiple sensing coils could work at different initial phases. Multiple signals of sensing coils could be combined into one output without information loss. Synchronized sampling is used for data recording, and output signals of multiple sensing coils are extracted from the recorded data. A four-channel wear debris sensor system was designed to demonstrate our method. Subsequently, crosstalk analysis, pseudo-dynamic testing and dynamic testing were conducted to check the sensing system. Results show that signals of four sensing coils could be simultaneously detected and the detection limit for ferrous wear debris is 33 μm. Using the presented method, real time wear debris detection in multiple channels could be achieved without increasing the number of excitation source and data acquisition equipment.

Switched Model and Dynamic Analysis of a Hydroturbine Governing System in the Process of Load Rejection Transient

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Huanhuan Li ◽  
Diyi Chen ◽  
Feifei Wang ◽  
Hao Zhang
Keyword(s):  
Mathematical Model ◽  
Dynamic Analysis ◽  
Numerical Simulations ◽  
Dynamic Characteristics ◽  
Nonlinear Dynamic ◽  
Hydropower Station ◽  
Transfer Coefficients ◽  
Operational Conditions ◽  
Governing System ◽  
Hammer Impact

In this paper, we pay attention to studying the switched model of the hydroturbine governing system (HTGS) by introducing the concept of the switching of operational conditions. More specifically, utilizing the data of an existent hydropower station in China, we propose six nonlinear dynamic transfer coefficients of the hydroturbine, which can better describe the dynamic characteristics of the HTGS in the process of load rejection transient. Moreover, the elastic water hammer-impact of the penstock system and the nonlinearity of the generator for the process of load rejection transient are considered. Based on the combination of the different regulation modes of the governor and the corresponding running conditions of the hydroelectric generating unit, a novel nonlinear dynamic switched mathematical model of the HTGS is finally established. Meanwhile, the nonlinear dynamic behaviors of the governing system are exhaustively investigated using numerical simulations. These methods and analytical results will provide some theory bases for running a hydropower station.

Performance Characterization of Pressure Sensors Using an Improved Pressure Square Wave Generator

2005 ◽  
Vol 295-296 ◽  
pp. 533-538 ◽  
Author(s):  
Tsing Tshih Tsung ◽  
Lee Long Han ◽  
Liang Chia Chen ◽  
Ho Chang
Keyword(s):  
Dynamic Characteristics ◽  
Dynamic Testing ◽  
Dynamic Pressure ◽  
Pressure Sensors ◽  
Hydraulic Systems ◽  
Frequency Wave ◽  
Square Wave ◽  
Gain Margin ◽  
Wave Generator ◽  
Square Wave Generator

The purpose of this paper is to analyze and compare the dynamic characteristics of various structure pressure sensors using the Improved Pressure Square Wave Generator (IPSWG). The developed IPSWG is a signal generator that creates pressure square waves as an excitation source. The dynamic characteristics of pressure sensor in hydraulic systems can be measured and evaluated effectively due to the high excitation energy. The method is also useful for dynamic testing and characterization for a high frequency range, which cannot be performed by the traditional methods, such as the hammer kit excitation, sweeping frequency pressure wave, and random frequency wave. Result shows that piezoelectric sensors (quartz) have a largest gain margin and overshoot. The strain gauge sensor has a smaller gain margin and overshoot. The piezoelectric sensor is more suitable for measuring dynamic pressure.

Measuring the dynamic characteristics of a shock-excited spectrum analyzer

1987 ◽  
Vol 30 (4) ◽  
pp. 328-331
Author(s):  
V. P. Trofimov ◽  
Yu. V. Ivanov
Keyword(s):  
Dynamic Characteristics ◽  
Spectrum Analyzer

Dynamic Testing and Analysis of Inflatable Beams

2012 ◽  
Vol 226-228 ◽  
pp. 546-552 ◽  
Author(s):  
Jian Zheng Wei ◽  
Hui Feng Tan ◽  
Jian Xin Yu ◽  
Xing Wen Du
Keyword(s):  
Thin Film ◽  
Internal Pressure ◽  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Dynamic Testing ◽  
Composite Fiber ◽  
Film Structure ◽  
The Self ◽  
Modal Damping ◽  
Local Stiffness

Dynamic testing of an inflatable beam has been performed to evaluate structural natural frequencies and modal damping ratios. The inflatable beam has a pattern of six composite fiber strips inside thin-film structure that increases its local stiffness that the structure can be self-supporting in the gravity environment when the internal pressure is released. A measurement setup was installed, and the dynamic testing was performed in this self-supporting state. Dynamic characters of the beams were tested with internal pressure or not when the beam had a 2.0kg mass on the top. Moreover, the dynamic characters before rolled up were contrasted to one after. The experimental results indicate that the self-supporting inflatable beams had better bending stiffness, and the curl folding process had an impact on the dynamic characteristics of the inflatable beam. The pressure affection is not obvious on dynamics of the beam.

scholarly journals Dynamic Characteristics in the Design of Maglev Suspensions

1994 ◽  
Vol 208 (1) ◽  
pp. 33-41 ◽  
Author(s):  
R Goodall
Keyword(s):  
Dynamic Characteristics ◽  
Transfer Functions ◽  
Controller Design ◽  
Design Method ◽  
Vehicle Speed ◽  
Passenger Comfort ◽  
Operational Conditions ◽  
Second Stage ◽  
Maglev Vehicle

The paper reviews the essential functions which apply to any kind of suspension, and distinguishes between the various inputs to which a suspension is subjected. These are used to assess the particular characteristics of an electromagnetically suspended (Maglev) vehicle, and to identify considerations which have important implications for the controller design, irrespective of the design method. Some general equations are developed which interrelate the vehicle speed, the quality of the track and the passenger comfort requirements, and these are used to identify operational conditions for which a second stage of suspension becomes necessary (that is, in addition to that provided by the magnets). The importance of understanding the suspension's response to deterministic track inputs is also highlighted. Although the paper is directed towards Maglev, the analysis is strongly based upon a consideration of the suspension transfer functions, and so many of the principles are applicable to actively controlled supensions in general.

Dynamic Testing of Magnetic Elastomer Material Prototypes

2019 ◽  
Vol 945 ◽  
pp. 369-373 ◽  
Author(s):  
A.J. Minaev ◽  
J.V. Korovkin
Keyword(s):  
Magnetic Field ◽  
Frequency Response ◽  
Dynamic Characteristics ◽  
Dynamic Testing ◽  
Considerable Effect ◽  
Experimental Results ◽  
New Materials ◽  
Resonant Frequencies ◽  
Input And Output ◽  
The Magnetic Field

This research is aimed at obtaining the experimental dynamic characteristics of new materials (magnetoactive elastomers exposed to the magnetic field). It demonstrates that the strength of a magnetic field has a considerable effect on the increase in the resonant frequencies of tested materials. For tests, we used a vibration stand equipped with virtual meters to visualize the experimental results on a computer display. We herein present an example of recording the frequency response on the magnetic elastomer sample input and output when exposed to vibrations caused by the unbalanced motor forces.

scholarly journals Diagnostic benchmarks on dynamic characteristics of thin-walled marine damaged structures

2019 ◽  
Vol 2 (1) ◽  
pp. 38-52
Author(s):  
Adam Szeleziński ◽  
Lech Murawski ◽  
Adam Muc
Keyword(s):  
Dynamic Characteristics ◽  
Welded Joints ◽  
Automatic Testing ◽  
Time Frequency ◽  
Ship Hulls ◽  
Thin Walled Structures ◽  
Damping Decrement ◽  
Recorded Data ◽  
Thin Walled ◽  
Vibration Tests

Abstract Among structural health monitoring (SHM) methods of thin-walled structures, a vibrodiagnostic method is one of the most promising. The accelerometer recorded responses provide diagnostic information that requires mathematical processing to extract the essential dynamic characteristics. The authors have been looking for new parameters - diagnostic benchmarks which can be applied to non-destructive, automatic testing of thin-walled marine structures (especially their welded joints) like ship hulls. All characteristics have been based on recorded data generated during the vibration tests of welded joints with and without failures. For this purpose, the authors proposed method based on: FFT windowing analysis, benchmark with using 2D or 3D time – frequency dynamic characteristics and the determination of damping decrement in function of time. The work presents the algorithm and exemplary results obtained from the application of proposed method to several selected sample plates with different type of welds.

Device for Converting Photographically Recorded Data to Computer‐Compatible Magnetic Tape

1968 ◽  
Vol 39 (8) ◽  
pp. 1131-1132
Author(s):  
Ian S. Glass ◽  
Kenneth F. Richard
Keyword(s):  
Magnetic Tape ◽  
Recorded Data
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