Evaluation of dynamic loads on a skew box girder continuous bridge Part II: Parametric study and dynamic load factor

2007 ◽  
Vol 29 (6) ◽  
pp. 1064-1073 ◽  
Author(s):  
Demeke B. Ashebo ◽  
Tommy H.T. Chan ◽  
Ling Yu
Keyword(s):  
Dynamic Load ◽  
Parametric Study ◽  
Dynamic Loads ◽  
Load Factor ◽  
Box Girder ◽  
Dynamic Load Factor

scholarly journals Numerical and experimental study of the dynamic factor of the dynamic load on the urban railway

2020 ◽  
Vol 29 (1) ◽  
pp. 195-202
Author(s):  
Tran Anh Dung ◽  
Mai Van Tham ◽  
Do Xuan Quy ◽  
Tran The Truyen ◽  
Pham Van Ky ◽  
...  
Keyword(s):  
Experimental Study ◽  
Dynamic Load ◽  
Dynamic Measurement ◽  
Experimental Results ◽  
Load Factor ◽  
Dynamic Factor ◽  
Experimental Measurements ◽  
Train Speed ◽  
Dynamic Load Factor

AbstractThis paper presents simulation calculations and experimental measurements to determine the dynamic load factor (DLF) of train on the urban railway in Vietnam. Simulation calculations are performed by SIMPACK software. Dynamic measurement experiments were conducted on Cat Linh – Ha Dong line. The simulation and experimental results provide the DLF values with the largest difference of 2.46% when the train speed varies from 0 km/h to 80 km/h

Parametric Instability of Tapered Beams by Finite Element Method

1982 ◽  
Vol 24 (4) ◽  
pp. 205-208 ◽  
Author(s):  
P. K. Datta ◽  
S. Chakraborty
Keyword(s):  
Finite Element ◽  
Dynamic Load ◽  
Parametric Instability ◽  
Mathieu Equation ◽  
Stability Diagram ◽  
Load Factor ◽  
Element Analysis ◽  
Load Factors ◽  
Principal Region ◽  
Dynamic Load Factor

The dynamic stability behaviour of a tapered beam has been studied using a finite element analysis. The instability zones of the parametric stability diagram have been discussed for the entire ranges of static and dynamic load factors. It has been observed that at high values of static load and beyond a particular value of the dynamic load factor, the periodic solution of the Mathieu equation does not exist in the principal region. This leads to unstable behaviour due to large displacement of the beam due to increasing values of static and dynamic load factors.

Dynamic Load Factor for Surge Load on Pipe Using the Stress Wave Propagation Methodology

2017 ◽  
Author(s):  
Abu Seena
Keyword(s):  
Wave Propagation ◽  
Dynamic Load ◽  
Time History ◽  
Stress Wave Propagation ◽  
Load Factor ◽  
Full Time ◽  
Maximum Value ◽  
Force Time ◽  
Full Force ◽  
Dynamic Load Factor

The full time history method for calculating the pipe stresses and restraint loads due to transient flow event requires high computing memory and long simulation time. Alternately, the static equivalent method has been extensively used in power and process industry where a dynamic load factor is used to account for the dynamic amplification response of suddenly applied surge/hammering loads on pipe. In practice, the DLF is multiplied on the maximum value of dynamic force depending on the time rise of load. Due to the complexity of calculating DLF, the engineers adopt maximum value of DLF = 2.0 irrespective of the load variation. The present paper discusses the uncertainty and inaccuracy involved in performing approximate analysis or static equivalent analysis and shows the significance and need of performing full force time history analysis. A new methodology has been derived for the estimation of approximate DLF from the full force time history profiles. Using the stress wave propagation methodology, the DLF can be estimated for the pipe with axial restraints and guides. The axial line stoppers are precondition to apply present method, which can be easily included during design phase of the pipe routes. The DLF’s are computed for sample force curve with various other parameters and are compared with the FEA results. It has also been shown that the load amplification does not scale with the displacement amplification. With proposed methodology the DLF for can be calculated for each pipe. Then it is recommended to perform the static analysis with the estimated DLF’s based on full time history profiles.

scholarly journals Dynamic loads in self-aligning gear transmissions of heavy loaded machines

2021 ◽  
pp. 84-90
Author(s):  
B. V. Vinogradov ◽  
D. O. Fedin ◽  
V. I. Samusia ◽  
D. L. Kolosov
Keyword(s):  
Relative Motion ◽  
Dynamic Load ◽  
Ball Mill ◽  
Rigid Body Dynamics ◽  
Gear Transmission ◽  
Dynamic Loads ◽  
Load Factor ◽  
Misalignment Angle ◽  
Drive Gear ◽  
Ball Mills

Purpose. Development of a mathematical model of a heavy loaded gear transmission with a self-aligning drive gear; evaluation of the dynamic load on the gear transmission in the gear alignment process. Methodology. The calculation schematic and equations of the relative motion of the self-aligning drive gear are formed using the methods of rigid body dynamics. Analytical expressions for the gear self-alignment time, collision velocity during the alignment and dynamic load factor are obtained by integrating an ordinary differential equation. Methods of the linear theory for oscillations are used to determine the dynamic factor. Findings. The article investigates the state-of-art design and mathematical models of the self-aligning gear. An equation for the relative motion of the moving part of the gear has been formed using the methods of rigid body dynamics. It is shown that by using the proposed hypotheses, the movement of the gear can be reduced to rotation about the instantaneous axis. The influence of geometric and dynamic parameters of the ball mill drive on dynamic loads in the open gear transmission is investigated. The gear alignment speed dependences on the tooth mesh misalignment angle in the gear transmission and the inertial parameters of the gear have been obtained. The obtained dependencies were used to calculate the time and speed of the gear alignment in the open gear transmission of the ball mill 5.5 6.5 (central discharge ball mill). It is shown that in the real range of mesh misalignment angles and gear parameters, the time of the gear alignment is several orders of magnitude less than the time of teeth re-engagement. In the presence of the variable component of the mesh misalignment angle, the gear will constantly make a relative motion with strikes; depending on the current value of the mesh misalignment angle, the dynamic load on the gear transmission can be significant. It is shown that when assessing the efficacy of self-aligning gears, it is necessary to take into account a possible increase in dynamic loads. The dynamic factor and the load factor are calculated for the nominal value of the mesh misalignment angle in the open gear transmission of 5.5 6.5 ball mills. Originality. A mathematical model of the dynamics of a self-aligning gear transmission in heavy duty machine drives has been developed. A quantitative assessment of internal dynamic load factor in an open gear transmission of 5.5 6.5 ball mills has been carried out. Practical value. A method for determining the dynamic component of the load on a gear transmission containing a self-aligning drive gear has been developed.

The Effects of Solid Viscosities to Dynamic Load Factors of the Ring and the Hollow Sphere Subjected to Impulsive Loads

1968 ◽  
Vol 72 (695) ◽  
pp. 971-976 ◽  
Author(s):  
Shin-Ichi Suzuki
Keyword(s):  
Hollow Sphere ◽  
Dynamic Load ◽  
Higher Dimensions ◽  
Point Of View ◽  
Load Factor ◽  
Vacuum Vessel ◽  
Load Factors ◽  
Impulsive Loads ◽  
Damped Oscillation ◽  
Dynamic Load Factor

Although it has been said that dynamic load factor is equal to 2, it became evident by the author's researches that this value is influenced by the dimensions of members and loading conditions and is very different from 2. However, the solid viscosities are neglected in all these researches. Previously, the author obtained the coefficients of viscosities from the experimental results of damped oscillation of a cantilever beam in a vacuum vessel and investigated the relationships between dynamic load factors and solid viscosities on the beam and the rod subjected to transverse or longitudinal impulsive loads. From these results, it was found that the effects of solid viscosities to dynamic load factors cannot be neglected. To find out whether the same fact can be obtained for the higher dimensions or not, the ring and the hollow sphere subjected to uniformly distributed impulsive loads along the inner and outer edges are analysed. Since σθ, the direct stress to the circumferential direction, is the most important from the engineering point of view, the relationships between solid viscosities and dynamic load factors of σθ are investigated.

scholarly journals Parametric Study on the Effects of Soil to Oscillation Velocity / Parametrická Studie Vlivu Typu Zeminy Na Amplitudu Rychlosti Kmitání

2012 ◽  
Vol 12 (2) ◽  
pp. 123-131 ◽  
Author(s):  
Tomáš Petřík ◽  
Eva Hrubešová ◽  
Martin Stolárik ◽  
Miroslav Pinka
Keyword(s):  
Mathematical Modeling ◽  
Finite Element Method ◽  
Finite Element ◽  
Soil Properties ◽  
Dynamic Load ◽  
Parametric Study ◽  
Civil Engineering ◽  
Dynamic Loads ◽  
Experimental Measurements ◽  
Oscillation Velocity

Abstract The paper focuses on the possibility of evaluating the influence of character of the soil to oscillations velocity induced dynamic loads. Mathematical modeling is used to solve the parametric study. Models are created in software Plaxis 2d based on finite element method. Dynamic load is based on experimental measurements on the stand in the area of the Faculty of Civil Engineering, VSB-TUO. Soil properties are determined from the normative indicative characteristics.

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