scholarly journals Simplified Analysis of Dynamic Structure–Ground Interaction

1975 ◽  
Vol 2 (3) ◽  
pp. 345-356 ◽  
Author(s):  
J. H. Rainer
Keyword(s):  
Dynamic Properties ◽  
Dynamic Structure ◽  
Elastic Half Space ◽  
Mode Shapes ◽  
Soil Material ◽  
Modal Damping ◽  
Flexible Foundations ◽  
Simplified Method ◽  
Simplified Analysis

A simplified method of analysis is presented for the determination of dynamic properties of single-story structures founded on flexible foundations. The general equations for natural frequency, mode shapes, and modal damping are applied to structures founded on an elastic half-space and on piles. The results of parameter studies, including the effects of hysteretic soil material damping, are presented for these two cases.

Simplified analysis of wall-frame structures

1978 ◽  
Vol 5 (2) ◽  
pp. 262-273 ◽  
Author(s):  
O. Moselhi ◽  
P. Fazio ◽  
Z. Zielinski
Keyword(s):  
Orthotropic Plate ◽  
Rapid Determination ◽  
Frame Structures ◽  
Direct Integration ◽  
Lateral Loads ◽  
Actual Structure ◽  
Simplified Method ◽  
Internal Forces ◽  
Simplified Analysis

A simplified method is presented for the analysis of planar, uniformly perforated walls under the action of lateral loads. The method is based on replacing the perforated wall by an elastically equivalent orthotropic plate. The principle of minimum total complementary potential energy is then used to determine stresses and displacements in the equivalent plate. Internal forces in the actual structure are obtained by direct integration of these stresses. An example is worked out to illustrate the application of the method and its accuracy. Design curves are presented for the rapid determination of internal forces.

Spray Car Workbench Racks of Modal Analysis

2015 ◽  
Vol 1094 ◽  
pp. 469-474
Author(s):  
Yu Jing He ◽  
Jiang Feng Shen ◽  
Xiang Fu Li
Keyword(s):  
Modal Analysis ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Dynamic Structure ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Support Frame

The author designed a intelligential spray car of fruit tree, this support frame of worktable support the whole spraying arm in the course, its dynamic properties is important to determine the product quality and life. On the basis of three-dimensional modeling, The modal of dynamic that support frame was analysis and the first ten modal parameters (natural frequencies and mode shapes) was calculated by using ANSYS finite element of analysis software. Compared with Modal parameters by method and experimental modal analysis obtained, summarizes the higher modes of dynamic structure, and proposed modifications for the structure.

scholarly journals Estimation of track parameters and wheel–rail combined roughness from rail vibration

2017 ◽  
Vol 232 (4) ◽  
pp. 1149-1167 ◽  
Author(s):  
Qi Li ◽  
David J Thompson ◽  
Martin GR Toward
Keyword(s):  
Dynamic Properties ◽  
Field Measurements ◽  
Element Model ◽  
Decay Rates ◽  
Cross Sectional ◽  
Simplified Method ◽  
Rolling Noise ◽  
Direct And Indirect Methods

Rolling noise from running trains is significantly influenced by the wheel–rail combined roughness and the dynamic properties of the track. To facilitate predictions of vibration and noise, it is desirable to be able to determine these parameters accurately from field measurements. In this study, an inverse method for the determination of these parameters is adopted and enhanced. A track model that is based on a wavenumber finite element model of the free rail coupled to discrete supports, which allows for the pinned–pinned mode and cross–sectional deformation of the rail, has been used. The rail vibration induced by hammer impacts and the vibration during train passages are simulated using this model, and these results are then applied to illustrate the accuracy of the direct and indirect methods for the estimation of track decay rate. These methods are compared in a case study for a ballasted track for which hammer impact and train pass–by measurements have been obtained. Other track parameters can also be extracted from the measured data by using the advanced track model. Thereafter, a more complete method is adopted to estimate the wheel–rail combined roughness from the measured rail vibration under train passages. A comparison is made among the estimated roughness levels obtained from this full method, an existing simplified method and the direct measurement method. It is found that the simplified method overestimates the roughness around the pinned–pinned resonance frequency, but gives a good estimation if the track decay rates of the loaded track are used.

Seismic response of multiple-story structures on flexible foundations

1969 ◽  
Vol 59 (3) ◽  
pp. 1061-1070
Author(s):  
Richard A. Parmelee ◽  
David S. Perelman ◽  
Seng-Lip Lee
Keyword(s):  
Seismic Response ◽  
Half Space ◽  
Dynamic Properties ◽  
Equations Of Motion ◽  
Elastic Half Space ◽  
Rigid Foundation ◽  
Flexural Response ◽  
Flexible Foundations ◽  
Constant Coefficients ◽  
Shear Buildings

abstract A method is presented for investigating the seismic response of multiple-story shear buildings on flexible elastic foundation media which are represented by an elastic half space. It is shown that the frequency dependent dynamic properties of the foundation medium may be assumed to be constant with respect to the frequency. This assumption leads to equations of motion with constant coefficients which are solved numerically. A study of several structure-foundation systems indicates that the flexibility of the foundation medium can increase or decrease the flexural response of the structure compared to the case of the rigid foundation.

scholarly journals Modal analysis and insights into damping phenomena of a special vibration chain

2021 ◽  
Author(s):  
Peter C. Müller ◽  
Wolfgang E. Weber
Keyword(s):  
Fluid Flow ◽  
Modal Analysis ◽  
Mode Shape ◽  
Mode Shapes ◽  
Hydraulic Systems ◽  
Practical Applications ◽  
Damping Matrix ◽  
Modal Damping ◽  
Future Work

AbstractVibration chains are of interest in many fields of practical applications. In this contribution, a modal analysis of the rather special Mikota’s vibration chain  is performed. Herein, focus is set on the mode shapes of this multibody oscillator, which was firstly introduced by Mikota as a solid body compensator in hydraulic systems for filtering out fluid flow pulsations. The mode shapes show interesting properties, e.g. an increase in the polynomial representing the coordinates of each mode shape with an increasing eigenfrequency associated with the respective mode shape. This and other properties are discussed exemplary. Some of these properties still have to be proven, which is the task of future work. Additionally, modal damping of Mikota’s vibration chain is discussed. Moreover, an approach for determining the damping matrix for given Lehr’s damping measures without knowing the mode shapes in advance is introduced. This approach involves the determination of a matrix root.

Effect of Bass Bar Tension on Modal Parameters of a Violin's Top Plate

2015 ◽  
Vol 39 (1) ◽  
pp. 145-149 ◽  
Author(s):  
Ewa B. Skrodzka ◽  
Bogumił B.J. Linde ◽  
Antoni Krupa
Keyword(s):  
Modal Analysis ◽  
Experimental Modal Analysis ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Normal Value ◽  
Modal Damping

Abstract Experimental modal analysis of a violin with three different tensions of a bass bar has been performed. The bass bar tension is the only intentionally introduced modification of the instrument. The aim of the study was to find differences and similarities between top plate modal parameters determined by a bass bar perfectly fitting the shape of the top plate, the bass bar with a tension usually applied by luthiers (normal), and the tension higher than the normal value. In the modal analysis four signature modes are taken into account. Bass bar tension does not change the sequence of mode shapes. Changes in modal damping are insignificant. An increase in bass bar tension causes an increase in modal frequencies A0 and B(1+) and does not change the frequencies of modes CBR and B(1-).

Automation of selected brazes' dynamic properties in high-temperatures' measurement process

2013 ◽  
Vol 18 (2-3) ◽  
pp. 33-41
Author(s):  
Dominik Sankowski ◽  
Marcin Bakala ◽  
Rafał Wojciechowski
Keyword(s):  
Surface Tension ◽  
High Temperatures ◽  
Dynamic Properties ◽  
Automatic Measurement ◽  
Measurement Methodology ◽  
Joining Process ◽  
Wetting Force ◽  
Research Grant

Abstract The good quality of several manufactured components frequently depends on solidliquid interactions existing during processing. Nowadays, the research in material engineering focuses also on modern, automatic measurement methods of joining process properties, i.a. wetting force and surface tension, which allows for quantitative determination of above mentioned parameters. In the paper, the brazes’ dynamic properties in high-temperatures’ measurement methodology and the stand for automatic determination of braze’s properties, constructed and implmented within the research grant nr KBN N N519 441 839 - An integrated platform for automatic measurement of wettability and surface tension of solders at high temperatures, are widely described

Applications of Thermal Analytical Procedures in the Study of Elastomers and Elastomer Systems

1980 ◽  
Vol 53 (3) ◽  
pp. 437-511 ◽  
Author(s):  
D. W. Brazier
Keyword(s):  
Thermal Analysis ◽  
Dynamic Properties ◽  
Evolved Gas Analysis ◽  
Gas Analysis ◽  
International Standards ◽  
New Technique ◽  
Heating Rates ◽  
Single Experiment ◽  
Rubber Compounds

Abstract An attempt has been made to review the development of thermoanalytical procedures as they have been applied to elastomers and elastomer systems over the past 10 years. For all rubber industry products, temperature and its effects, either alone or in conjunction with the chemical environment, play an important role from the production stage through to the final failure of the product in the field. It is thus not surprising that thermal analysis, in which temperature is the prime variable, has found such diverse applications in elastomer studies. The identification and quantitative analysis of rubber formulations have received most attention. Such formulations produce characteristic “fingerprints” when studied in DTA, DSC, TG, or TMA. In DSC, the determination of the glass transition characteristics, the observation and determination of crystallinity, the detection of cyclization reactions, and the monitoring of thermal and oxidative degradation characteristics can all be observed in a single experiment covering the temperature range from −150 to +600°C. At normal heating rates, e.g., 20°C/min, such information is available in 40 min. TG/DTG analysis can yield the elastomer or elastomers content, oil and plasticizer, carbon black (level and often type), and inorganic ash in less than 60 min. Processing and curing can also be studied. Blend compatibility can be assessed on the basis of both Tg and crystallinity measurements and the data used to determine optimum mixing times. Sulfur vulcanization and peroxide curing of elastomers is readily monitored by DSC and can be used for confirmation analysis of the presence of curatives. Limitations in such analysis exist, but as understanding and ability to interpret cure exotherms increase, valuable information about the mechanism and the nature of the cured network will be obtained. The testing of rubber compounds involves many hours of labor by current procedures. The rapidity of thermal analysis promises to offer some relief. In addition to DSC and TG, TMA, a relatively new technique, offers a rapid approach to low-temperature testing. Dynamic mechanical analysis (DMA) offers a rapid route to determining dynamic properties, but as yet, relatively little has been published on the application of this new technique to elastomers. As environmental concern increases, techniques such as evolved gas analysis (EGA) and combined techniques such as TG/gas chromatography are predicted to play an important role. As for the future, it is readily apparent that the principles of the methods have been established and, in several cases, it now remains to reduce them to a practical level. In some areas, such as vulcanization studies, much remains to be undertaken to improve our interpretive skills. Although there is some indication that certain industries have produced “in-house” standards for the analysis of rubber compounds by DSC and TG/DTG, it will only be when national and international standards organizations study and produce standard procedures, that the techniques will be generally adopted. Maurer's prediction in 1969 of increased applications of DTA and TG in elastomer studies has undoubtedly proved correct, and with the proliferation of reliable commercial instrumentation, significant developments can be anticipated in the next decade.

A Simplified Method for the Determination of Blood Urea*

1938 ◽  
Vol 8 (ts2_5) ◽  
pp. 153-157
Author(s):  
Fabry L. Hawk ◽  
Jerome E. Andes
Keyword(s):  
Simplified Method

scholarly journals High-Resolution NMR Determination of the Dynamic Structure of Membrane Proteins

2016 ◽  
Vol 55 (35) ◽  
pp. 10518-10521 ◽  
Author(s):  
Mariusz Jaremko ◽  
Łukasz Jaremko ◽  
Saskia Villinger ◽  
Christian D. Schmidt ◽  
Christian Griesinger ◽  
...  
Keyword(s):  
High Resolution ◽  
Membrane Proteins ◽  
Dynamic Structure ◽  
High Resolution Nmr
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