25074

طراحي و مدلسازي حسگر تشديدگر آگزتيك جهت تشخيص برخط بريدگي چرخ واگن باري

كارشناسي ارشد

مهندسي راه آهن گرايش ماشين هاي ريلي

1398

تير ماه 1400

دكتر داود يونسيان

مهندسي راه آهن

1400/05/16

Design and simulation of auxetic sensor for online detection of wheel flat in freight wagons

1/1/1900 12:00:00 AM

Wagon wheel flat is one of the most common defects in the railway industry, which is caused by the wheels locking during braking. Vibrations and force from the wheel flat can damage the rail components and tools or even lead to derailment. Inspecting train conditions in accordance with the traditional method, which takes place during specific maintenance intervals, wastes a lot of human resources and money. In addition, this method is not accurate enough and human error can be effective. Therefore, the design of an on-line condition monitoring sensor can be effective in detection of wheel flat. Because of limitation in electric power in freight wagons and high-cost batteries, building a self-powered sensor is a priority. In this project, an attempt has been made to identify the wheel flat by the vibrations of the axle box by using a single beam and piezoelectric element as a cost-effective and self-power sensor. The performance of the sensor in wheel flat detection with different depths, under different load conditions and different speeds has been investigated. In the following, an attempt has been made to increase the sensitivity of the sensor by simply changing the structure of the beam and without the need to change the geometry of the piezoelectric element or change the material. Auxetic structures with Negative Poisson ratio are among the metamaterials that have been considered in recent decades. Introducing the new auxetic structure and using it in a wheel flat detection sensor has shown a 2.3-time improvement in sensitivity compared to a simple sensor

بريدگي چرخ، تشخيص برخط، پيزوالكتريك، آگزتيك، حساسيت

wheel flat, online detection, piezoelectric, auxetic, sensitivity