Experimental Investigation of Spur Gear Tooth Crack Location and Depth Detection Using Short-Time Averaging Method and Statistical Indicators

Document Type: Original Article


Gear systems are one of the most functional power transmission systems in the industry. Crack is one of the common defects in gears which is caused by excessive loading, sudden impact and shortcomings in the gears construction. Initially, the crack will not result in structure collapse, but its growth can lead to irreparable damage. Therefore, detecting the crack and determining its location and depth are very efficient in this respect. In this paper, two encoders are used to obtain the spur gear pair transmission error speed. Moreover, the short-time averaging method (STAM) has been proposed thereby detecting the crack location and some statistical indicators have been used to estimate the crack depth in the spur gear tooth. For this purpose, a dynamical model in which mesh stiffness varying with time has been deployed to achieve the transmission error speed of the gear system. Additionally, a gear test rig including a single-stage gearbox, two encoders, and also an electronic board has been used. Encoders are installed on input and output shafts and the angular position of each shaft in time is saved in the computer using the electronic board. In addition, the transmission error speed is obtained by analyzing the received signals. Then, short-time averaging method has been used to identify the crack location. Ultimately, some indicators such as ABS-max, FM0, Energy Ratio (ER) and Residual Signal Average are applied to the simulated results and experimental signals to find the crack depth ratio. According to theresults of this study, ...