scholarly journals Nonlinear Dynamic Analysis of Lifting Mechanism of an Electric Overhead Crane during Emergency Braking

2020 ◽  
Vol 10 (23) ◽  
pp. 8334
Author(s):  
Congmin Niu ◽  
Huajiang Ouyang
Keyword(s):  
High Speed ◽  
Virtual Work ◽  
Thermal Power ◽  
Nonlinear Dynamic Analysis ◽  
Maximum Load ◽  
Rigid Bodies ◽  
Dynamic Responses ◽  
Response Analysis ◽  
Emergency Braking ◽  
Braking Process

Mechanical brakes are essential for electric cranes when emergency braking occurs. This paper presents, for the first-time, a dynamic response analysis of emergency braking events of electrical cranes that has modelled crane components as flexible and rigid bodies. Based on the Hamilton principle, a nonlinear and non-smooth dynamic model is derived from a modified Lagrangian function and the virtual work of non-conservative forces. The dynamic responses of a 32-ton overhead travelling crane during the emergency braking process of its lifting mechanism with two service brakes determined by simulating realistic operations. The numerical results show that the loads acting on components of the crane during the braking process depend on the braking capacity and the action time of the mechanical brakes, as well as the magnitude and the initial position of the payload. When a dual-brake scheme of the lifting mechanism is adopted, the maximum load of the high-speed links and the maximum thermal power of the mechanical brake appear in the emergency braking process when one of the two brakes fails to work. In addition, it is found to be a false belief that the lower the initial speed, the lower the maximum loads acting on components of cranes become during the braking process.

The Vibration Response Analysis about High-Speed Train’s Braking Wing

2012 ◽  
Vol 226-228 ◽  
pp. 102-105
Author(s):  
Wen Qing Zhu ◽  
Yang Yong Zhu
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Rapid Development ◽  
Response Analysis ◽  
High Speed Train ◽  
High Speed Railway ◽  
Emergency Braking ◽  
Finite Element Software ◽  
High Speed Trains ◽  
Aerodynamic Brake

With the rapid development of high-speed railway in China, the aerodynamic brake is very likely to be an important emergency braking mode of high-speed train in the future. This paper takes aerodynamic braking wing as the object, and uses the finite element software to divide the meshes, then analyses the model influenced by static stress. After simulating the vibratory frequency response of the model in the flow field, it finds that the largest deformation happens in the middle of the upper edge of the wind wing, when the wind speed gets to 500km/h and the load frequency to 4Hz. Some conclusions of this thesis can provide reference for researching the applying the aerodynamic brake in the high-speed trains and laying the foundation for solving the riding and braking safety problems.

Dynamic response analysis of the brake disc of a high-speed train with wheel flats

2021 ◽  
pp. 095440972110317
Author(s):  
Zhiwei Wang ◽  
Jiliang Mo ◽  
Micheale Yihdego Gebreyohanes ◽  
Kaiyun Wang ◽  
Junyong Wang ◽  
...  
Keyword(s):  
Stress State ◽  
High Speed ◽  
Dynamic Properties ◽  
High Stress ◽  
Rigid Bodies ◽  
Response Analysis ◽  
Brake Disc ◽  
Dynamics Model ◽  
Coupled Dynamics ◽  
Brake Discs

To study the vibration characteristics and stress state of brake discs during vehicle operations, a spatial trailer car-track coupled dynamics model was developed with the consideration of flexible brake disc. In the model, the components of a trailer car are considered as rigid bodies. Flexible models of the brake disc and wheelset were established using the finite element method. The trailer car-track coupled dynamics model is validated using experimental test results. The effects of wheelset flexible deformation on the dynamic properties of brake discs were investigated with the excitations of track irregularity and wheel flats. Furthermore, the brake disc was systematically evaluated and discussed under the condition of wheel flats in the coupled dynamics system. The results indicate that compared to rigid wheelsets with wheel flats, flexible wheelsets can cause the brake disc to vibrate more severely with higher stress. The severe vibration and high stress state of the brake disc could cause it to crack in the region near the bolts. The established dynamics model can be further developed and employed to assess the dynamics of the brake systems of high-speed trains.

Effect of Matrix Alloying on Braking Performance of Copper-Based Brake Pad Under Continuous Emergency Braking

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Peng Zhang ◽  
Lin Zhang ◽  
Dongbin Wei ◽  
Xuanhui Qu
Keyword(s):  
Friction Coefficient ◽  
Friction Surface ◽  
High Speed ◽  
High Strength ◽  
Brake Pad ◽  
Braking Performance ◽  
Emergency Braking ◽  
Ni Content ◽  
Improved Stability ◽  
Braking Process

Abstract The continuous emergency braking performance of copper-based brake pads alloyed with different Ni contents were tested. The results showed that the copper-based brake pad with high Ni content exhibits improved stability of friction coefficient during the whole emergency braking process, which indicates that Ni helps to reduce the sensitivity of the brake pad to the change of braking conditions. Moreover, the fade phenomenon of friction coefficient is obviously alleviated as the increase in Ni content under high-pressure and high-speed braking conditions. The introduction of Ni enhances the plastic deformation resistance of friction surface and promotes the formation of high-strength mechanical mixed layer and thick tribo-oxide film. This stable tribo-film remained on the contact interface is responsible for the steady mean friction coefficient under different braking conditions. Excessive addition of Ni reduces the plasticity of the friction surface, leading to the change of the main wear mechanism from adhesive wear to delamination

Virtual Work & d’Alembert’s Principle

2018 ◽  
Author(s):  
Peter Mann
Keyword(s):  
Euler Equations ◽  
Virtual Work ◽  
Lagrange Equation ◽  
Classical Mechanics ◽  
Rigid Bodies ◽  
Gibbs Function ◽  
Constraint Force ◽  
Appell Equations ◽  
Jourdain's Principle ◽  
D'alembert's Principle

This chapter discusses virtual work, returning to the Newtonian framework to derive the central Lagrange equation, using d’Alembert’s principle. It starts off with a discussion of generalised force, applied force and constraint force. Holonomic constraints and non-holonomic constraint equations are then investigated. The corresponding principles of Gauss (Gauss’s least constraint) and Jourdain are also documented and compared to d’Alembert’s approach before being generalised into the Mangeron–Deleanu principle. Kane’s equations are derived from Jourdain’s principle. The chapter closes with a detailed covering of the Gibbs–Appell equations as the most general equations in classical mechanics. Their reduction to Hamilton’s principle is examined and they are used to derive the Euler equations for rigid bodies. The chapter also discusses Hertz’s least curvature, the Gibbs function and Euler equations.

scholarly journals High Speed EIT With Multifrequency Excitation Using FPGA and Response Analysis Using FDM

2020 ◽  
Vol 20 (15) ◽  
pp. 8698-8710
Author(s):  
Mathieu Darnajou ◽  
Antoine Dupre ◽  
Chunhui Dang ◽  
Guillaume Ricciardi ◽  
Salah Bourennane ◽  
...  
Keyword(s):  
High Speed ◽  
Response Analysis

Dynamic Analysis of DVG 850 High-Speed Machining Center

2012 ◽  
Vol 487 ◽  
pp. 203-207
Author(s):  
Gong Xue Zhang ◽  
Xiao Kai Shen
Keyword(s):  
High Speed ◽  
Simulation Analysis ◽  
Response Analysis ◽  
Improved Method ◽  
Analysis Software ◽  
Element Analysis ◽  
Harmonic Response ◽  
Machining Center ◽  
Calculation Results ◽  
Harmonic Response Analysis

Purpose, with the application of workbench finite element analysis software, get the analysis results of DVG 850 high-speed vertical machining center via the modal analysis and harmonic response analysis. Use the calculation results for reference, put forward the improved method, and prove the credibility of the simulation analysis by testing DVG 850 prototype.

scholarly journals Analysis study the used of Tuned Mass Damper (TMD) on an existing train bridge due to high speed train with moving mass load approach

2019 ◽  
Vol 258 ◽  
pp. 05005 ◽  
Author(s):  
Wivia Octarena Nugroho ◽  
Dina Rubiana Widarda ◽  
Oryza Herdha Dwyana
Keyword(s):  
High Speed ◽  
Tuned Mass Damper ◽  
Dynamic Responses ◽  
Mass Ratio ◽  
High Speed Train ◽  
Maximum Deformation ◽  
Mass Load ◽  
Mass Damper ◽  
Existing Bridges ◽  
Comfort Criteria

As the need of the train speed increased, the existing bridges need to be evaluated, especially in dynamic responses, which are deformation and acceleration. In this study, Cisomang Bridge is modeled and analyzed due to the high-speed train SJ X2 in varying speeds, 50 km/h, 100 km/h, 150 km/h, and 200 km/h. The used of tuned mass damper also will be varied on its setting and placing. The tuned mass dampers setting be varied based on the first or second natural frequency and the placing of tuned mass damper be varied based on maximum deformation of the first or second mode. Moreover, the tuned mass damper ratio will be varied 1% and 1.6%. For all speed variations, dynamic responses of structure without TMD still fulfil the Indonesian Government Criterion based on PM 60 - 2012 but do not meet requirement of comfort criteria based on DIN-Fachbericht 101. Furthermore, only for the speed train 50km/h dynamic responses of structure fulfil safety criteria based on Eurocode EN 1990:2002, whereas the other speed variations do not meet that requirement. In the use of TMD 1% mass ratio, the structure fulfils the safety criteria for all speed variations. In the use of TMD 1.6% mass ratio, all the structure fulfils the safety and comfort criteria except 100 km/h speed which only fulfils the safety criteria.

Estimation of bridge static response and vehicle weights by frequency response analysis

1998 ◽  
Vol 25 (4) ◽  
pp. 631-639 ◽  
Author(s):  
G Thater ◽  
P Chang ◽  
D R Schelling ◽  
C C Fu
Keyword(s):  
Dynamic Effect ◽  
Dynamic Responses ◽  
Response Analysis ◽  
Static Response ◽  
Actual Weight ◽  
Service Testing ◽  
Weigh In Motion ◽  
Moving Vehicles ◽  
Bridge Structures ◽  
Truck Weight

A methodology is developed to more accurately estimate the static response of bridges due to moving vehicles. The method can also be used to predict dynamic responses induced by moving vehicles using weigh-in-motion (WIM) techniques. Historically, WIM is a well-developed technology used in highway research, since it has the advantage of allowing for the stealthy automatic collection of weight data for heavy trucks. However, the lack of accuracy in determining the dynamic effect in bridges has limited the potential for its use in estimating the fatigue life of bridge structures and their components. The method developed herein amends the current WIM procedures by filtering the dynamic responses accurately using the Fast Fourier Transform (FFT). Example applications of the proposed method are shown by using computer-generated data. The method is fast and improves the predicted truck weight up to 5% of the actual weight, as compared to errors up to 10% using the current WIM methods.Key words: weigh-in-motion, digital filters, FFT, bridge dynamics, in-service testing.

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