Dynamic Response of an Elastic-Supported Bridge Beam Subjected to Velocity-Varied Moving Loads

2012 ◽  
Vol 594-597 ◽  
pp. 2802-2807
Author(s):  
Fu Liang Mei ◽  
Gui Ling Li
Keyword(s):  
Dynamic Response ◽  
Beam Theory ◽  
Dynamic Responses ◽  
Force Model ◽  
Superposition Method ◽  
Moving Loads ◽  
Coupled Vibration ◽  
Vehicle Model ◽  
Vibration Model ◽  
Mass Spring

Dynamic response of an elastic-supported bridge under speed-varied moving loads was investigated. A mathematical model of vehicle-bridge coupled oscillation for an elastic-supported bridge was built up by means of 1/4 vehicle model (Mass-Spring-Mass) and Euler-Bernoulli beam theory. And then dynamic equations of vehicle-bridge coupled oscillation in matrix form were established using two former orders general coordinates of an elastic-supported beam and model superposition method. The influences of vehicle-bridge coupled vibration model, elastic-supported stiffness, entrance speeds and acceleration /deceleration of moving loads on the dynamic responses of bridges were studied. Vehicle-bridge coupled vibration model based on 1/4 vehicle model can more accurately describe the dynamic characters of bridges than that based on constant moving force model. Elastic-supported stiffness only has an impact on the fluctuation amplitudes of dynamic responses. The vehicle-induced impact factor is dependent on the entrance speeds, acceleration/deceleration of moving loads and elastic-supported stiffness.

scholarly journals Multi-moving Loads Induced Vibration of FG Sandwich Beams Resting on Pasternak Elastic Foundation

2021 ◽  
Vol 18 (9) ◽  
Author(s):  
Wachirawit SONGSUWAN ◽  
Monsak PIMSARN ◽  
Nuttawit WATTANASAKULPONG
Keyword(s):  
Dynamic Response ◽  
Elastic Foundation ◽  
Excitation Frequency ◽  
Beam Theory ◽  
Equation Of Motion ◽  
Functionally Graded ◽  
Sandwich Beams ◽  
Moving Loads ◽  
Layer Thickness Ratio ◽  
Pasternak Elastic Foundation

The dynamic behavior of functionally graded (FG) sandwich beams resting on the Pasternak elastic foundation under an arbitrary number of harmonic moving loads is presented by using Timoshenko beam theory, including the significant effects of shear deformation and rotary inertia. The equation of motion governing the dynamic response of the beams is derived from Lagrange’s equations. The Ritz and Newmark methods are implemented to solve the equation of motion for obtaining free and forced vibration results of the beams with different boundary conditions. The influences of several parametric studies such as layer thickness ratio, boundary condition, spring constants, length to height ratio, velocity, excitation frequency, phase angle, etc., on the dynamic response of the beams are examined and discussed in detail. According to the present investigation, it is revealed that with an increase of the velocity of the moving loads, the dynamic deflection initially increases with fluctuations and then drops considerably after reaching the peak value at the critical velocity. Moreover, the distance between the loads is also one of the important parameters that affect the beams’ deflection results under a number of moving loads.

Dynamic Response of Vehicle-Bridge Coupled Oscillation Subjected to Velocity-Varied Moving Loads

2012 ◽  
Vol 226-228 ◽  
pp. 1555-1560
Author(s):  
Fu Liang Mei ◽  
Gui Ling Li
Keyword(s):  
Mathematical Model ◽  
Coupled Model ◽  
Superposition Method ◽  
Moving Loads ◽  
Vertical Movements ◽  
Coupled Vibrations ◽  
Coupled Oscillations ◽  
Acceleration And Deceleration ◽  
Mass Spring ◽  
The Mathematical Model

A mathematical model of vehicle-bridge coupled oscillations for a simple-supported bridge beam subjected to speed-varied moving loads was established according to TFDVM and model superposition method. This model can consider the pitching and vertical movements of a vehicle. By contrast to a vehicle-bridge oscillation coupled model based on one-freedom-degree Mass-Spring-Mass vehicle model (OFDMSMVD), the mathematical model of vehicle-bridge coupled vibrations based on TFDVM can more accurately reflect the dynamic behaviors of vehicle-bridge coupled vibrations .The maximum middle-span deflections of bridges under speed-varied cases are not linearly proportional to the entrance speeds of moving loads, and they happen at a number of entrance speed points of moving loads. The influence of acceleration and deceleration of moving loads on the dynamic deflections of bridges is dependent on the entrance speeds of moving loads.

In Plane Radial Vibration of Uncracked and Cracked Circular Curved Beams Subjected to Moving Loads

2021 ◽  
pp. 2150146
Author(s):  
Jatin Poojary ◽  
Sankar Kumar Roy
Keyword(s):  
Dynamic Response ◽  
Moving Load ◽  
Real Life ◽  
Beam Theory ◽  
Point Of View ◽  
Curved Beam ◽  
Moving Loads ◽  
Curved Beams ◽  
Beam Elements ◽  
Curved Beam Element

The dynamic response of structures subjected to moving load is a subject of great importance from a practical point of view. In this work, the in-plane dynamic response of a cracked isotropic circular curved beam subjected to moving loads is investigated using the finite element method. The curved beam is modeled using curved beam elements, which is developed based on the Timoshenko beam theory. Furthermore, a cracked curved beam element is developed to incorporate the presence of cracks in the structure. The effect of moving load speed, depth, and the location of the crack on the dynamic response of the beam is investigated. The outcome of the work can be useful in the study of real-life moving load problems like bridges and railways and also in the field of condition monitoring using moving loads.

Dynamic Response of Multi-bay Frames Subjected to Successive Moving Forces

2019 ◽  
Vol 19 (04) ◽  
pp. 1950042
Author(s):  
Salih Demirtas ◽  
Hasan Ozturk ◽  
Mustafa Sabuncu
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Moving Load ◽  
Single Point ◽  
Vertical Direction ◽  
Point Load ◽  
Dynamic Responses ◽  
Moving Loads ◽  
Element Analysis ◽  
Constant Interval

This paper investigates the dynamic responses of multi-bay frames with identical bay lengths subjected to a transverse single moving load and successive moving loads with a constant interval at a constant speed. The effects of the bay length and the speed of the moving load on the response of the multi-bay frame subjected to a single point load are investigated numerically by the finite element method. A computer code is developed by using MATLAB to perform the finite element analysis. The Newmark method is employed to solve for the dynamic responses of the multi-bay frame. With this, the dynamic response of the frame subjected to successive moving loads with a constant interval is investigated. Also, the resonance and cancellation speeds are determined by using the 3D relationship of speed parameter-force span length to beam length ratio-dynamic magnification factor and the associated contour lines. The maximum impact factor of a 1-bay frame and multi-bay frames under single moving load are determined at the specific speed parameters. Those values are independent of elastic modulus, area moment of inertia, beam/column lengths of the frame and also the number of bays forming the frame. It is also found that the first resonance response in the vertical direction of the frame is related to the second mode of vibration.

The Influences on Turnout Dynamic Responses due to its Irregularities

2011 ◽  
Vol 105-107 ◽  
pp. 1181-1186 ◽  
Author(s):  
Yang Cao ◽  
Wang Ping ◽  
Wei Hua Zhao ◽  
Cai You Zhao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Response ◽  
Structure Design ◽  
Simulation Software ◽  
Dynamic Responses ◽  
Dynamics Simulation ◽  
Combined Effects ◽  
Vehicle Model ◽  
The Stability

A vehicle model and a movable-point simple turnout model were established, and the influences on dynamic responses caused by turnout irregularities when train passes through No.18 turnout was analyzed by using the turnout dynamics simulation software based on finite element method. It shows that turnout dynamic responses are influenced by the combined effects of various types of irregularities, which produce bigger dynamic response than single irregularity. In the turnout devise and use, the distance between slide plate and switch rail or nose rail should be as close as possible, the position arrangements of traction points should be optimized and the insufficient displacement should be eliminated as much as possible; No.18 turnout structure design is reasonable, which can ensure the safety and the stability when train passes over turnout.

scholarly journals Seismic Analysis of Coupled High-Speed Train-Bridge with the Isolation of Friction Pendulum Bearing

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Xinmin Hong ◽  
Wenhua Guo ◽  
Zihao Wang
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Seismic Analysis ◽  
Simulation Method ◽  
Dynamic Responses ◽  
Superposition Method ◽  
High Speed Train ◽  
Mode Superposition Method ◽  
Friction Pendulum ◽  
Bridge System

The paper presents a framework for the seismic analysis of the coupled high-speed train-bridge with the isolation of friction pendulum bearing (FPB). Taking the rail irregularities as system’s self-excitation with the seismic as external excitation, the equation of motion of the train-bridge coupled system under earthquake is built up. A five-span simple-supported railway bridge is taken as an example, and the computer simulation method is used to establish the dynamic model of the train-bridge system with the isolation of FPB under earthquake. A train composed of eight 4-axle coaches of 35 degrees-of-freedom (DOF) is considered, and FPB is simulated by a force element which includes both nonlinear spring and damper characteristics and a hysteresis function. Backward differentiation formula and the mode superposition method are adopted in the calculation of coupling vibration of the train-bridge system. The dynamic responses of the train running on the bridge with the isolation of FPB and with the common spherical bearing (CSB) under earthquake are studied. The results show that FPB with a friction coefficient no less than 0.05, instead of CSB, can reduce the dynamic response of the train greatly; the faster the train speed and the higher the pier, the greater the effect of FPB. However, FPB may increase the dynamic response of the train when the seismic intensity exceeds 0.14 g.

scholarly journals Coupled dynamic response of a three-column mini TLP

2010 ◽  
Vol 6 (2) ◽  
pp. 52-61 ◽  
Author(s):  
Anitha Joseph ◽  
Lalu Mangal ◽  
Precy Sara George
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Wave Force ◽  
Dynamic Responses ◽  
Design Stage ◽  
Force Model ◽  
Diffraction Radiation ◽  
Offshore Platforms ◽  
Scaled Model ◽  
Geometric Configurations

For the development of deepwater marginal fields, many new platform concepts and designs are on the anvil. The mini TLP is a proven concept in this regard wherein an optimised conventional TLP system economically and efficiently serves in developing small marginal deepwater reserves. Various new geometric configurations and designs of mini TLPs are reported in the literature. This paper presents a new geometric configuration which could be a better alternative to an existing configuration. A 3-column mini TLP is designed and its platform-mooring coupled dynamic behaviour is investigated and compared with an existing 4-column mini TLP. The numerical investigation is carried out for the 1:56 scaled model using a finite element computer program suitable for compliant offshore platforms. A combination wave force model with diffraction-radiation loading on large members and Morison loading on slender members is adopted for computing the non-linear dynamic response of the structure. The effects of parameters such as pretension in tethers and wave approach angle have been studied. The results obtained are compared with published results of the 4-column mini TLP. It is found that the dynamic responses of the 3-column mini TLP are close to the 4-column mini TLP with relatively higher surge and tether tension.  Accounting for this in the design stage, the newly designed structure could be a promising candidate which can be used as an alternative to the 4-column mini TLP. Reducing the number of columns from four to three has added advantages in terms of cost and time during fabrication, installation and maintenance of the platform. Keywords: Deepwater structures; Coupled dynamics; Finite element method; Mini TLP; Nonlinear dynamicanalysis. DOI: 10.3329/jname.v6i2.2789

Influence of the Lubrication Model on the Dynamic Response of Mechanical Systems

2013 ◽  
Author(s):  
Paulo Flores
Keyword(s):  
Dynamic Response ◽  
Reynolds Equation ◽  
Hydrodynamic Force ◽  
Equations Of Motion ◽  
Mechanical Systems ◽  
Hydrodynamic Forces ◽  
Journal Bearings ◽  
Dynamic Responses ◽  
Force Model ◽  
Revolute Joints

The main objective of this work is to present a study on the use of different hydrodynamic force models on the dynamic response of mechanical systems with lubricated revolute joints. For this purpose, the fundamental issues related to the classical theory of lubrication for dynamically loaded journal-bearings are revised, which is used to evaluate the Reynolds’ equation for dynamic regime. The hydrodynamic forces that develop at the lubricated revolute joints are determined and included into the dynamic equations of motion. In this study, three different approaches are considered to evaluate the hydrodynamic forces, namely the Pinkus and Sternlicht approach for long journal-bearings and the Frêne et al. models for both long and short journal-bearings. Results for a mechanical system with a lubricated revolute joint are presented and used to discuss the main assumptions and procedures adopted in this work. From the computational simulations performed, it can be observed that the hydrodynamic force model play a crucial role in predicting the dynamic behavior of mechanical systems and originate some uncertainties in their dynamic responses.

Evaluation for Dynamic Performance of Simple-Continuous Bridge

2011 ◽  
Vol 250-253 ◽  
pp. 1360-1365
Author(s):  
Ke Jian Sheng ◽  
Zong Lin Wang
Keyword(s):  
Vibration Amplitude ◽  
Dynamic Performance ◽  
Influential Factors ◽  
Dynamic Responses ◽  
Coupled Vibration ◽  
Vehicle Model ◽  
Structural Dynamic ◽  
Standard Design ◽  
Dynamic Performances ◽  
Traveling Speed

It is necessary to study the dynamic responses of simple-continuous bridges under traveling vehicles action, which may benefit the improvement of their dynamic performances. According to “Standard Design Drawings” issued by Ministry of Communications of PRC, this paper considers the alterations of span length, decking width and sectional style and the differences of vehicle model and traveling speed, and calculates separately dynamic response of these structures with the “vehicle-bridge coupled vibration program”. As two key influential factors, vibration amplitude and acceleration are applied for the evaluation of structural dynamic performance. The results show that dynamic performance of simple-continuous cored slab bridge is deficiency in some degree.

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