PSI - Issue 32

I.O. Glot et al. / Procedia Structural Integrity 32 (2021) 216–223 Shestakov A.P./ Structural Integrity Procedia 00 (2021) 000 – 000

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metal and consists of load-bearing columns, interconnected by horizontal and inclined links. The height of the structure is 64 meters. The appearance of the structure at the time of construction and in the finished state is shown in Fig. 1. As part of the organization of the monitoring system, 8 single-component high-frequency accelerometers and three component low-frequency accelerometers are installed on the structure. The scheme of their installation is shown in Fig. 2a. The sensors are evenly distributed throughout the structure. This configuration allows the definition of flexural and torsional mode shapes of the structure. Also, the location of the sensors is dictated by the sources of technological vibrations. The HFS1 and HFS2 sensors are located in the areas of the wheel supports (not shown in Fig. 2), which rotate when the ore is lifted and create additional vibrations. Sensors HF5, HFS6, HFS7 and LFS3 are located in the ore drop zone. The HFS8 sensor is designed to register vibrations from the conveyor. The frequency ranges of high-frequency and low-frequency sensors – from 0.5 to 10000 Hz and from 0.3 to 400 Hz, respectively. Data collection was performed synchronously using two analog-to-digital conversion boards. To exclude the ingress of an aggressive environment, the sensors are closed with external cases. 3. Selection of technological processes During operation, the structure can be in the following states: free - technological devices do not function; lifting of ore; dropping of ore into the storage; the work of the conveyor. Ore raises in series. Figure 3 shows a series of 15 lifts. This figure on the left shows the modulus average acceleration values for the HFS1, HFS5 and HFS8 sensors. These graphs make it possible to unambiguously determine the technological operation of the headframe. Figure 3 on the right shows vibrograms corresponding to one rise, one drop and turn on the conveyor. Based on the data from these sensors, a program has been developed that automatically records vibrograms corresponding to technological operations. The program runs on a schedule once a day, records vibrograms corresponding to each technological operation and goes into standby mode.

Fig. 3. Average amplitudes of signals from sensors HF1, HF5 and HF8 corresponding to one series of lifts. The frames on the right show vibrograms for time intervals indicated by ovals.