Train-based Rapid Ultrasonic Scanning of Track (TRUST)

铁路故障由于横向表面和近表面裂缝的铁路头，腹板或脚是澳大利亚和国际铁路行业的重大问题。由于裂缝对列车造成的危险，目前必须对轨道进行频繁检查，这扰乱了铁路网的正常交通。研制铁路轨道裂纹超声检测系统。虽然已经存在用于此目的的超声波系统，但我们提出的系统在一些关键方面有所不同，这赋予了它独特的优势。首先，我们将使用电磁声换能器（EMATs）代替传统的超声波换能器。由于emat在金属轨道表面电磁产生和检测超声波，因此它们不需要直接与金属轨道接触，而是能够在轨道表面上方几毫米处工作。因此，EMAT系统适合部署在快速行驶的列车上，包括一些客运和货运列车，而不是像目前的系统那样依赖于专门改装的低速检测车。其次，将面波检测与角入射剪切垂直体波检测相结合。表面波检查将沿着钢轨顶部发送超声波，以查看钢轨表面因与列车车轮接触而产生的裂纹。同时，一个有角度的超声波波束将从轨道的底部（脚）反弹，以寻找在重复载荷循环的轨道底部可能发生的罕见但更严重的裂缝。这两种技术都使用了一个螺距捕捉EMAT对，通过同一对探头调制驱动频率来进行两种检测也有一定的可能性，这将在项目过程中进行研究。作为TRUST项目的一部分，我们打算通过制造和部署一个合适的“探头”来演示该系统在高速检测中的应用，该探头可以在标准轨道上高速行驶，并获得一小段轨道或旋转“高速模拟器”轨道轮的使用，以便进行高速试验。这个项目的成功将使我们能够进入下一步，开发一个更全面的系统版本，可以部署在商业列车和轨道上进行测试。

Rail failures due to transverse surface and near surface cracks in the railhead, web or foot are significant problems for the Australian and international rail industry. Because of the danger to trains posed by cracking, currently frequent inspections of the tracks must be made, which disrupts normal traffic on the rail network. We will develop an ultrasonic system for detecting cracks on railway tracks. While ultrasonic systems already exist for this purpose, our proposed system differs in some key respects that give it unique advantages.Firstly, we will use electromagnetic acoustic transducers (EMATs) instead of conventional ultrasonic transducers. Because EMATs generate and detect ultrasound electromagnetically on the surface of the metal rails, they do not need to be directly in contact with them, instead being capable of operating a few millimetres above the surface of the rail. Therefore, an EMAT system is suitable for deployment on fast-moving trains, including some passenger and freight trains, instead of relying on specially adapted low-speed inspection cars as current systems do.Secondly, we will combine surface wave inspection with angled-incidence shear-vertical bulk wave inspection. The surface wave inspection will send ultrasonic waves along the top of the rail to look at cracks in the surface of the rail caused by contact with the train wheels. At the same time an angled ultrasonic beam will be bounced off the bottom (foot) of the rail to look for the rarer but more serious cracking that can occur at the base of the rail to repeated load cycling. Both these techniques use a pitch-catch EMAT pair, and there is some potential scope for running both inspections through the same pair of probes with modulation to the drive frequency, which will be investigated during the course of the project.As part of the TRUST project, we intend to demonstrate the use of this system for high-speed inspection by making and deploying a suitable "probe head" that can ride on standard rail track at a high speed and acquiring the use of a small stretch of track or a rotating "high-speed simulator" rail wheel in order to perform the high-speed trials. The success of this project will allow us to go on to the next step of developing a more comprehensive version of the system that can be deployed for testing on commercial trains and tracks.