A review of the modelling of wheel/rail noise generation

Real-time power line rating may be provided. First, sensor data may be received corresponding to a conductor of a power line. The sensor data may provide real-time weather conditions for the conductor's environment. The sensor data may be received from a sensor device configured to collect the sensor data. The sensor data may correspond to the weather conditions at a location of the sensor device on the power line. Next, design limitations for the power line having the conductor may be received. The conductor of the power line may have a design ampacity based upon the design limitations and assumed weather conditions for the conductor's environment. Then a dynamic ampacity may be calculated for the power line based upon the received sensor data and the received design limitations for the power line. The power line may then be operated according to the calculated dynamic ampacity instead of the design ampacity.

Real-time power line rating

Mechanical energy flow models of rods and beams

Summary High-frequency train-track interaction and mechanisms of wheel/rail wear that is non-uniform in magnitude around/along the running surface are surveyed. Causes, consequences and suggested remedies to relieve the problems are discussed for three types of irregular wheel/rail wear: (1) short-pitch rail corrugation on tangent tracks and large radius curves, (2) wheel corrugation as caused by tread braking, and (3) wheel polygonalisation. The state-of-the-art in modelling of dynamic train-track interaction in conjunction with prediction of irregular wear is reviewed.

Train-Track Interaction and Mechanisms of Irregular Wear on Wheel and Rail Surfaces

The estimation of material properties is important for scene understanding, with many applications in vision, robotics, and structural engineering. This paper connects fundamentals of vibration mechanics with computer vision techniques in order to infer material properties from small, often imperceptible motions in video. Objects tend to vibrate in a set of preferred modes. The frequencies of these modes depend on the structure and material properties of an object. We show that by extracting these frequencies from video of a vibrating object, we can often make inferences about that object's material properties. We demonstrate our approach by estimating material properties for a variety of objects by observing their motion in high-speed and regular frame rate video.

Visual Vibrometry: Estimating Material Properties from Small Motions in Video

A comprehensive analytical model of the wayside noise generated by a railroad wheel rolling on straight track is presented. The model assumes that the small‐scale roughness on the running surfaces of the wheel and rail is the primary mechanism for the noise generation. Included in the model are such effects as the spatial filtering of the roughness due to the finite area of contact between the wheel and rail; the interaction between the wheel and rail, including local contact stiffness; axial response of the wheel; the radiation efficiencies of the wheel and rail; and the influence of sound propagation, including finite ground impedance.

Wheel/rail rolling noise, I: Theoretical analysis

This article reviews Structure-Borne Sound: Structural Vibrations and Sound Radiation at Audio Frequencies (3rd Edition) by L. Cremer, M. Heckl, B. A. T. Petersson , Berlin, 2005. 607 pp. Price: $199.00 (hardcover), ISBN: 3540226966.

Structure-Borne Sound: Structural Vibrations and Sound Radiation at Audio Frequencies (3rd Edition)

An analytical model for the prediction of wheel/rail noise is validated through comparison with measurements made using the state‐of‐the art car (SOAC) on a test track. Predictions of wheel and rail vibrations and wayside noise are seen to agree reasonably well with measurements although areas of uncertainty remain. Model improvements to reduce discrepancies between theory and measurement are discussed.

Wheel/rail rolling noise, II: Validation of the theory

Statistical Energy Analysis (SEA) predictions of the power flow between two multimodal dynamic systems, i.e., two rods vibrating in compression, are compared with an exact calculation. The exact calculation when averaged in sufficiently broad frequency bands is found to agree closely with the SEA predictions for both strong and weak coupling.Subject Classification: 45.40.

Comparison of Statistical Energy Analysis power flow predictions with an ’’exact’’ calculation

An active control device for reducing high-speed impulsive (“HSI”) and blade vortex interaction (“BVI”) noise in a rotor aircraft, such as a helicopter, is disclosed. The system comprises a plurality of rotor blades extending radially in spaced relationship from a central hub, each of the blades having spaced apart upper and lower surfaces, an interior volume between the surfaces, and leading and trailing edges at the respective joined edges of the upper and lower surfaces. Air intake passages are disposed on the surfaces of each blade proximate the leading edge to controllably admit air into the interior volume; and air output passages are disposed on the surfaces of each blade proximate the trailing edge and the outer edge tip to controllably expel air from the interior volume of the blade. Admitting and expelling of air into and out of the interior volume of each blade is controlled in accordance with a determined condition of that blade. When the presence of BVI or HSI noise, or any condition giving rise to such noise, is sensed, the admittance and expulsion of air is activated to minimize the noise.

Paul J. Remington

Papers

Wheel/rail rolling noise, I: Theoretical analysis

Structure-Borne Sound: Structural Vibrations and Sound Radiation at Audio Frequencies (3rd Edition)

Wheel/rail rolling noise, II: Validation of the theory

Comparison of Statistical Energy Analysis power flow predictions with an ’’exact’’ calculation

Use of flow injection and extraction to control blade vortex interaction and high speed impulsive noise in helicopters