Stop Braking Research Articles

The Application of Automobile Lamp Filament Information for Accident Reconstruction(Deforming Characteristics for Headlight Lamp Filament and Braking Stop Lamp Filament by Impact Force)

The Application of Automobile Lamp Filament Information for Accident Reconstruction(Deforming Characteristics for Headlight Lamp Filament and Braking Stop Lamp Filament by Impact Force)

Coupled effect between damage and elastoviscoplasticity of type 28CrMoV5-08 steel under complex loading

This paper is devoted to the study of the coupled effect between damage and elastoviscoplasticity of the 28CrMoV5-08 steel used in railway brake discs under thermomechanical loading. Isothermal and anisothermal experimental uniaxial cyclical traction-compression tests on cylindrical samples are carried out to identify the fatigue damage law and the number of cycles to fracture versus temperature. An application of the coupled constitutive equations to the stress analysis of real railway brake discs under two types of stop braking is given. The obtained cycled curves are compared with others deduced from a simple model without damage.

Thermal cracking in railroad vehicle wheels subjected to high performance stop braking

An investigation of thermal cracks observed in the wheels of certain electric multiple unit (EMU) locomotives in North American commuter rail service is summarized. The cause is found to be partial reversal of the wheel rim residual hoop stress, which is initially compressive from the manufacturer's quench treatment. The residual stress reversal is caused by thermal stresses during high performance stop braking. Crack propagation and failure mechanisms are summarized. Measures for prevention are discussed.

Braking controllers and steering controllers for combination vehicles

Methods for deriving braking controllers and steering controllers for combination vehicles (i.e. low–vehicle and trailer(s) combinations) are described. Central to the development of these controllers is a vehicle model in which the tyre forces are represented as bilinear functions of wheelslip and slipangle. This tyre force representation is valid for tyre forces below saturation levels. It captures the essential trade–off between cornering forces and braking or accelerating forces. Moreover, when the bilinear equations are substituted into the equations of motion, the resulting vehicle model is bilinear. This is important because a large family of control strategies is available for bilinear systems. These control strategies are based on Lyapunov Theory. Many forms of controllers can be derived. In this paper an emergency stop braking controller, a stability enhancement braking controller, and a steering controller are derived. Simulation results are presented to demonstrate the performance of the braking controllers.

Brake Discs for Passenger Trains—a Theoretical and Experimental Comparison of Temperatures and Stresses in Solid and Ventilated Discs

The ventilated brake discs currently used in passenger trains can be replaced with solid discs when drag braking of long duration need not be designed for. This is a conclusion arrived at in the present study where transient temperatures and stresses induced in the disc during drag braking and during single and repeated stop braking are calculated by use of a previously established analytical model. The results are verified through full-scale experiments carried out on a recently built inertia dynamometer. A forged solid steel disc is compared with a standard ventilated cast iron disc. Measurement techniques and various observations are discussed.

Fatigue Durability of Tread-Braked Railway Wheels—on Admissible Combinations of Axle Load, Train Speed and Signalling Distance

A mathematical model for the prediction of relative lifetimes of railway wheels exposed to block braking under stop braking cycles is presented. Analytical and finite element thermoelastic calculations are employed together with a model for low-cycle fatigue. Durability curves are established describing limiting combinations of axle load and train speed for given combinations of signalling distance and required wheel lifetime. Application of the method is demonstrated on an existing freight car wheel which conforms to UIC standards. The numerical results should also be useful for other wheels.