Verification of Dynamic Load Factor for Analysis of Airblast-Loaded Membrane Shelter Panels by Nonlinear Finite Element Calculations

1991 ◽  
Author(s):  
Thomas A. Godfrey
Keyword(s):  
Finite Element ◽  
Dynamic Load ◽  
Nonlinear Finite Element ◽  
Load Factor ◽  
Finite Element Calculations ◽  
Dynamic Load Factor

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.

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

scholarly journals Evaluation of Dynamic Load Factors for a High-Speed Railway Truss Arch Bridge

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Ding Youliang ◽  
Wang Gaoxin
Keyword(s):  
Finite Element ◽  
Dynamic Load ◽  
High Speed ◽  
Field Monitoring ◽  
Generalized Extreme Value Distribution ◽  
Monitoring Data ◽  
Load Factor ◽  
High Speed Railway ◽  
Arch Bridge ◽  
The Impact

Studies on dynamic impact of high-speed trains on long-span bridges are important for the design and evaluation of high-speed railway bridges. The use of the dynamic load factor (DLF) to account for the impact effect has been widely accepted in bridge engineering. Although the field monitoring studies are the most dependable way to study the actual DLF of the bridge, according to previous studies there are few field monitoring data on high-speed railway truss arch bridges. This paper presents an evaluation of DLF based on field monitoring and finite element simulation of Nanjing DaShengGuan Bridge, which is a high-speed railway truss arch bridge with the longest span throughout the world. The DLFs in different members of steel truss arch are measured using monitoring data and simulated using finite element model, respectively. The effects of lane position, number of train carriages, and speed of trains on DLF are further investigated. By using the accumulative probability function of the Generalized Extreme Value Distribution, the probability distribution model of DLF is proposed, based on which the standard value of DLF within 50-year return period is evaluated and compared with different bridge design codes.

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.

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.

The Dynamic Load Factor of Pressure Vessels in Deflagration Events

2011 ◽  
Author(s):  
Yu Xu ◽  
Kuao-John Young
Keyword(s):  
Case Studies ◽  
Dynamic Load ◽  
Static Pressure ◽  
Pressure Vessels ◽  
Load Factor ◽  
Suggested Procedure ◽  
Pressure Load ◽  
Load Effects ◽  
Dynamic Load Factor

There are vessels that could be subjected to rapidly rising pressure load during deflagration events. The dynamic load factor (DLF) which accounts for dynamic load effects in such events can be used to bridge the gap between transient and static pressure loads. This paper addresses the issues in estimating the DLF for a deflagration event. A unified methodology for estimating the DLF is first presented. The methodology is then validated with existing references. Key parameters determining DLFs are identified during the validation. Case studies are used to illustrate how to use the methodology. Finally, this paper is concluded with the findings and a suggested procedure for estimating DLFs in deflagration events.

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