Railway Track Vibration Analysis and Intelligent Recognition of Fastener Defects

Abstract

The rail fastener is an indispensable component used to connect the rail and sleepers in the track structure. Real-time recognition of the fastener defects plays a vital role in ensuring the safe and stable operation of rail transit. In this paper, an intelligent and innovative method is proposed to detect the fastener defects including the invisible defects appearing as bolt loosening and the visible defects such as the worn or completely missing fasteners by using axle-box vibration acceleration and deep learning network. First, the dynamical relation between the fastener defects and the axle-box vibration acceleration is investigated by using the first principle and the vehicle-track dynamical model. Then a defects recognition network is built based on the deep convolution neural network for track fasteners by using the frequency spectrum images of the axle-box vibration. The results show that the proposed method achieves a classification accuracy of 98.27%. Finally, the track section where the fasteners are most likely to be damaged is investigated, and rail corrugation is found to be a key factor that causes fastener fatigue.

Evacuation Simulation of a Passenger Ship Fire Based on a Modified Cellular Automaton

“…The behavior of following other evacuees unfamiliar with exits is affected by all evacuees within their perceptual radius, and the direction with a high probability of movement is selected during evacuation. The transition probability of an evacuee unfamiliar with an exit is defined as: (11) where, n is the eight directions available for a cell, with a value range of [1,2,…,8]; F n is the number of evacuees familiar with exits in a single direction within the perceptual radius; N total is the total number of evacuees in eight directions within the perceptual radius.…”

“…The numerical simulation methods can reasonably evaluate the effect of fire on evacuees. [11,12] In recent years, scholars have made many valuable achievements in evacuation modeling. [13,14] Evacuation simulation models can be divided into macro-models and micro-models.…”