Effect of Prestress on Bridge–Vehicle Interactions

2015 ◽  
Author(s):  
Hai Zhong ◽  
Mijia Yang
Keyword(s):  
Degrees Of Freedom ◽  
Virtual Work ◽  
Interaction Model ◽  
Dynamic Interaction ◽  
Vertical Acceleration ◽  
Vehicle Speed ◽  
Principle Of Virtual Work ◽  
Vehicle Model ◽  
Multiple Vehicles ◽  
4 Degrees Of Freedom

Prestress applied on bridges affects the dynamic interaction between bridges and vehicles traveling over them. In this paper, the prestressed bridge is modeled as a beam subjected to eccentric prestress force at the two ends, and a half-vehicle model with 4 degrees of freedom is used to represent the vehicle passing the bridge. A new bridge–vehicle interaction model considering the effect of prestress with eccentricity is developed through the principle of virtual work. The correctness and accuracy of the model are validated with literature results. Based on the developed model, numerical simulations have been conducted using the Newmark’s β method to study the effects of vehicle speed, eccentricity and amplitude of the prestress, and presence of multiple vehicles. It is shown that prestress has an important effect on the maximum vertical acceleration of vehicles, which may provide a good index for detecting the change of prestress. It is also interesting to find that the later-entering vehicle on the prestressed bridge will largely reduce the maximum vertical acceleration of the vehicle ahead of it.

scholarly journals Effect of Prestress on Bridge–Vehicle Interactions

2017 ◽  
Vol 4 (3) ◽  
Author(s):  
Hai Zhong ◽  
Mijia Yang
Keyword(s):  
Numerical Simulations ◽  
Degrees Of Freedom ◽  
Virtual Work ◽  
Interaction Model ◽  
Dynamic Interaction ◽  
Vertical Acceleration ◽  
Vehicle Speed ◽  
Principle Of Virtual Work ◽  
Vehicle Model ◽  
Multiple Vehicles

Prestress applied on bridges affects the dynamic interaction between bridges and vehicles traveling over them. In this paper, the prestressed bridge is modeled as a beam subjected to eccentric prestress force at the two ends, and a half-vehicle model with four degrees-of-freedom is used to represent the vehicle passing the bridge. A new bridge–vehicle interaction model considering the effect of prestress with eccentricity is developed through the principle of virtual work. The correctness and accuracy of the model are validated with literature results. Based on the developed model, numerical simulations have been conducted using Newmark's β method to study the effects of vehicle speed, eccentricity and amplitude of the prestress, and presence of multiple vehicles. It is shown that prestress has an important effect on the maximum vertical acceleration of vehicles, which may provide a good index for detecting the change of prestress. It is also interesting to find that the later-entering vehicle on the prestressed bridge will largely reduce the maximum vertical acceleration of the vehicle ahead of it.

Partially conforming plate bending elements for static and dynamic analyses

1973 ◽  
Vol 8 (4) ◽  
pp. 260-263 ◽  
Author(s):  
C T F Ross
Keyword(s):  
Degrees Of Freedom ◽  
Natural Frequencies ◽  
Virtual Work ◽  
Plate Bending ◽  
Principle Of Virtual Work ◽  
Displacement Method ◽  
Dynamic Analyses ◽  
The Matrix ◽  
Three Degrees Of Freedom ◽  
General Convergence

Two partially conforming flat-plate bending elements have been developed for static and dynamic analyses through the principle of virtual work. One of these elements is triangular and the other quadrilateral and both have corner nodes only, with three degrees of freedom per node. By use of these elements in the matrix displacement method, the natural frequencies of vibration of a square cantilevered plate have been calculated; these calculated results have been compared with experimental results. Agreement has been found to be good, and in general, convergence appears to take place.

Rollover stability of a vehicle during critical driving manoeuvres

2007 ◽  
Vol 221 (9) ◽  
pp. 1041-1049 ◽  
Author(s):  
Z L Jin ◽  
J S Weng ◽  
H Y Hu
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Front Wheel ◽  
Front Axle ◽  
Stability Factor ◽  
Vehicle Speed ◽  
Vehicle Model ◽  
Steering Angle ◽  
Vehicle Rollover ◽  
The Stability

In this paper, a linear vehicle model with three degrees of freedom is established to study the stability of vehicle rollover due to critical driving manoeuvres. From the linear vehicle model, the stability conditions are determined on the basis of the Routh-Hurwitz criterion, and a so-called dynamic stability factor is defined to reveal the effects of system parameters on the stability of vehicle rollover. In order to demonstrate the theoretical results, two numerical examples are given for the rollover of a sport utility vehicle in cornering and lane-change manoeuvres at a high speed and large steering angle. The stability regions are shown with respect to the vehicle speed and the vehicle parameters, such as the longitudinal distance from the centre of gravity to the front axle, and the steering angle of the front wheel.

A method for selecting driving system parameters of a new electric shovel's excavating mechanism with three-DOF

2011 ◽  
Vol 225 (11) ◽  
pp. 2661-2672 ◽  
Author(s):  
B Wei ◽  
F Gao ◽  
J Chen ◽  
J He ◽  
X Zhao
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Virtual Work ◽  
Transmission Ratio ◽  
Principle Of Virtual Work ◽  
Driving System ◽  
Generalized Coordinates ◽  
System Parameters ◽  
Three Degrees Of Freedom ◽  
Selection Of

Driving system parameters include motor parameters and transmission ratio of the reducer. In this study, a new three-degrees-of-freedom parallel excavating mechanism of electric shovel is analysed for the selection of its driving system which consists of three sub-driving parts. Based on the principle of virtual work in the form of generalized coordinates, the dynamic model of the excavating mechanism is established to calculate the external inertia loads and force (or torque) loads. For this parallel excavating mechanism which has three sub-drives, the external inertia loads cannot be fully divided into three independent parts with respect to these three sub-driving systems. Hence, the dynamic model of the system is employed to get loads characteristic of three sub-driving systems in the excavating process. Thus, the parameters' range of the motors can be obtained and then the best transmission ratio of every reducer can be obtained.

scholarly journals The Control of an Active Seat Suspension Using an Optimised Fuzzy Logic Controller, Based on Preview Information from a Full Vehicle Model

Vibration ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 20-40 ◽  
Author(s):  
Abdulaziz Alfadhli ◽  
Jocelyn Darling ◽  
Andrew Hillis
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Logic Controller ◽  
Ride Comfort ◽  
Vertical Direction ◽  
Front Axle ◽  
Rule Base ◽  
Vertical Acceleration ◽  
Vehicle Speed ◽  
Vehicle Model ◽  
Full Vehicle

The use of suspension preview information obtained from a quarter vehicle model (QvM) to control an active seat has been shown by the authors to be very promising, in terms of improved ride comfort. However, in reality, a road vehicle will be subjected to disturbances from all four wheels, and therefore the concept of preview enhanced control should be applied to a full vehicle model. In this paper, different preview scenarios are examined, in which suspension data is taken from all or limited axles. Accordingly, three control strategies are hypothesized—namely, front-left suspension (FLS), front axle (FA), and four wheel (4W). The former utilises suspension displacement and velocity preview information from the vehicle suspension nearest to the driver’s seat. The FA uses similar preview information, but from both the front-left and front-right suspensions. The 4W controller employs similar preview information from all of the vehicle suspensions. To cope with friction non-linearities, as well as constraints on the active actuator displacement and force capabilities, three optimal fuzzy logic controllers (FLCs) are developed. The structure of each FLC, including membership functions, scaling factors, and rule base, was sequentially optimised based on improving the seat effective amplitude transmissibility (SEAT) factor in the vertical direction, using the particle swarming optimisation (PSO) algorithm. These strategies were evaluated in simulation according to ISO 2631-1, using different road disturbances at a range of vehicle forward speeds. The results show that the proposed controllers are very effective in attenuating the vertical acceleration at the driver’s seat, when compared with a passive system. The controller that utilised suspension preview information from all four corners of the car provided the best seat isolation performance, independent of vehicle speed. Finally, to reduce the implementation cost of the “four suspension” controller, a practical alternative is developed that requires less measured preview information.

Dynamic interaction of vehicles moving on uniform bridges

2002 ◽  
Vol 216 (4) ◽  
pp. 343-350 ◽  
Author(s):  
N Jalili ◽  
E Esmailzadeh
Keyword(s):  
Degrees Of Freedom ◽  
Practical Importance ◽  
Beam Theory ◽  
Bending Moment ◽  
Dynamic Interaction ◽  
Suspension Bridges ◽  
Vehicle Speed ◽  
Varying Coefficients ◽  
Moving Vehicles ◽  
Time Varying Coefficients

The dynamic interaction problem of moving vehicles on uniform suspension bridges is studied. The resulting variable moving loads acting on the bridge are of great practical importance to both bridge and automotive engineers. The vehicle, including the occupants, is modelled as a planar half-car with six degrees of freedom, and the bridge is assumed to obey the Euler-Bernoulli beam theory with arbitrary conventional boundary conditions. However, the numerical simulations presented here are for the case of a vehicle travelling at a constant speed on a bridge with simply supported end conditions. Owing to the continuously moving location of the loads on the bridge, the governing differential equations will have time-varying coefficients and hence become rather complicated. The relationship between the bridge vibration characteristics and the vehicle speed is established, resulting in a search for a particular speed that determines the maximum values of dynamic deflection and the bending moment of the bridge.

Nonlinear Finite Element Analysis for Galloping of Iced Quad-Bundled Conductor

2013 ◽  
Vol 470 ◽  
pp. 232-235
Author(s):  
Li Qin ◽  
Ya Nan Li ◽  
Xiao Guang Wei
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
Virtual Work ◽  
Nonlinear Finite Element Analysis ◽  
Aerodynamic Characteristics ◽  
Nonlinear Finite Element ◽  
Principle Of Virtual Work ◽  
Element Analysis ◽  
Beam Elements

Based on the differences aerodynamic characteristics between each sub-conductor of iced bundled conductors, a two-node cable element with three translational and one torsional degrees of freedom at each node is utilized to imitate the bundled conductor and the two-node space beam elements are used to simulated the spacers. Established nonlinear finite element equations of bundled conductors based on the principle of virtual work and solved these equations using Newmark-β method. Numerical example was employed to demonstrate the reliable and efficient of the presented method and program.

On the Mechanical Behavior of the Orthotropic Cord-Rubber Composite

1976 ◽  
Vol 4 (4) ◽  
pp. 219-232 ◽  
Author(s):  
Ö. Pósfalvi
Keyword(s):  
Mechanical Behavior ◽  
Uniaxial Tension ◽  
Elastic Properties ◽  
Large Deformations ◽  
Virtual Work ◽  
Poisson's Ratio ◽  
Principle Of Virtual Work ◽  
Effective Elastic Properties ◽  
Rubber Composite ◽  
Mooney Equation

Abstract The effective elastic properties of the cord-rubber composite are deduced from the principle of virtual work. Such a composite must be compliant in the noncord directions and therefore undergo large deformations. The Rivlin-Mooney equation is used to derive the effective Poisson's ratio and Young's modulus of the composite and as a basis for their measurement in uniaxial tension.

scholarly journals Smartphone monitoring of in-ambulance vibration and noise

2021 ◽  
pp. 095441192098599
Author(s):  
Tom Partridge ◽  
Lorelei Gherman ◽  
David Morris ◽  
Roger Light ◽  
Andrew Leslie ◽  
...  
Keyword(s):  
Transport Systems ◽  
Vertical Acceleration ◽  
Vehicle Speed ◽  
Noise Levels ◽  
The Road ◽  
Neonatal Transport ◽  
Mass Data ◽  
Transport Team ◽  
Vertical Accelerations ◽  
Noise Vibration

Transferring sick premature infants between hospitals increases the risk of severe brain injury, potentially linked to the excessive exposure to noise, vibration and driving-related accelerations. One method of reducing these levels may be to travel along smoother and quieter roads at an optimal speed, however this requires mass data on the effect of roads on the environment within ambulances. An app for the Android operating system has been developed for the purpose of recording vibration, noise levels, location and speed data during ambulance journeys. Smartphone accelerometers were calibrated using sinusoidal excitation and the microphones using calibrated pink noise. Four smartphones were provided to the local neonatal transport team and mounted on their neonatal transport systems to collect data. Repeatability of app recordings was assessed by comparing 37 journeys, made during the study period, along an 8.5 km single carriageway. The smartphones were found to have an accelerometer accurate to 5% up to 55 Hz and microphone accurate to 0.8 dB up to 80 dB. Use of the app was readily adopted by the neonatal transport team, recording more than 97,000 km of journeys in 1 year. To enable comparison between journeys, the 8.5 km route was split into 10 m segments. Interquartile ranges for vehicle speed, vertical acceleration and maximum noise level were consistent across all segments (within 0.99 m . s−1, 0.13 m · s−2 and 1.4 dB, respectively). Vertical accelerations registered were representative of the road surface. Noise levels correlated with vehicle speed. Android smartphones are a viable method of accurate mass data collection for this application. We now propose to utilise this approach to reduce potential harmful exposure, from vibration and noise, by routing ambulances along the most comfortable roads.

scholarly journals Discrete element model for general polyhedra

2021 ◽  
Author(s):  
Alfredo Gay Neto ◽  
Peter Wriggers
Keyword(s):  
Frictional Contact ◽  
Virtual Work ◽  
Particle Surface ◽  
Element Model ◽  
Discrete Element ◽  
Discrete Element Model ◽  
Principle Of Virtual Work ◽  
Dynamics Model ◽  
Railway Ballast ◽  
Multibody Dynamics Model

AbstractWe present a version of the Discrete Element Method considering the particles as rigid polyhedra. The Principle of Virtual Work is employed as basis for a multibody dynamics model. Each particle surface is split into sub-regions, which are tracked for contact with other sub-regions of neighboring particles. Contact interactions are modeled pointwise, considering vertex-face, edge-edge, vertex-edge and vertex-vertex interactions. General polyhedra with triangular faces are considered as particles, permitting multiple pointwise interactions which are automatically detected along the model evolution. We propose a combined interface law composed of a penalty and a barrier approach, to fulfill the contact constraints. Numerical examples demonstrate that the model can handle normal and frictional contact effects in a robust manner. These include simulations of convex and non-convex particles, showing the potential of applicability to materials with complex shaped particles such as sand and railway ballast.

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