The Research Of On-line Non-destruct Detection Instrument For The Railway Vehicle Wheels

Flaw of the railway vehicle wheels, especially the crack of the wheel tread, is the most potential trouble for the accident. The main detection means used in china is manual, that is hearing, listening and touching by workers, which cannot check out mini-crack in the wheels. Furthermore, because of stops time and workers amounts limited, not all of wheels can be detected, which result in the detection, be worried. The increasing running speed as well as the enhancing crack and abrasion cause the manual detection cannot meet the demand of modern high-speed railway. So it is realistic to research an on-line wheel detection instrument. This paper presents a detection instrument based on electromagnetic acoustic that can detect every wheel of the entering vehicle timely and quickly.Firstly, the paper researches the crack styles of wheels and its extending law. Secondly, according to the peculiarity and request of the non-destruct detection of the wheel, the paper designs a non-destruct detection instrument with electromagnetic acoustic surface wave based on electromagnetic acoustic theory. Designing of the instrument includes the electromagnetic acoustic transducer (EMAT), the system scheme and the assistant mechanic system. Thirdly, the paper research the math module of the EMAT, and analyze the key components EMAT with simulation step by step based on finite element (FET) software, the simulation includes static magnetic field, the pulsed eddy current distribution field, the force distributing field and the fluctuating field, and educes the inner parameter and the outer measuring parameter influence to the EMAT in order to optimize the parameter of the EMAT. At last, the paper discusses briefly the further research aspects.