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Calculation model of headframe Table 1. Results of headframe calculations – equivalent stress according to Huber-Mises hypothesis
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The condition of headframes in underground mines has a substantial effect on the proper operation and safety of hoisting equipment. One of the potential problems that might occur during operation is the tilting of these structures, which can lead to difficulties in operation and, in extreme cases, to failures. The paper presents an original method...
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Designers of hydraulically driven machines and devices are obliged to ensure during design process their high service life with taking into account their operational conditions. Some of the machines may be started in low ambient temperature and even in thermal shock conditions (due to delivering hot working medium to cold components). In order to p...
Citations
... The traditional design method cannot calculate the dynamic characteristics of a large headframe, but also cannot analyze the dynamic response of a large headframe under the coupling action of the vibration loads of various components of the hoisting system, such as the head sheave, the motor, and the wire rope. As a result, resonance, structural damage, deflection, and settlement may occur in the later application of the large headframe [8][9][10][11][12]. Therefore, dynamic characteristic analysis is of great significance for the structural optimization design of a large headframe. ...
A large headframe is the core structure of a mine hoisting system. In the traditional design, only the static analysis under load is considered, resulting in the resonance phenomenon of the large headframe in later applications. In order to restrain the resonance phenomenon, a novel method for dynamic characteristic analysis and structural optimization design of a large headframe is proposed. First, the eigenfrequencies and vibration modes of the large headframe were obtained through modal analysis. The results showed that the numerical values of the multi-order eigenfrequencies of the system are relatively close. When subjected to alternating loads of similar frequencies, a large headframe is prone to the resonance phenomenon. Second, the steady-state vibration response of the large headframe was obtained through harmonic response analysis. The results showed that when the frequency of the alternating load is close to the first-order eigenfrequency, the vibration amplitude increases. Meanwhile, the fourth-order and the fifth-order eigenfrequencies are very close. When subjected to alternating loads of similar frequencies, the fourth-order and the fifth-order vibration modes of the headframe will be excited simultaneously. At this time, the headframe will have a strong resonance, which may cause structural damage and other problems. Finally, based on the above analysis, nine different structural optimization schemes are proposed in this paper. Through modal analysis and harmonic response analysis, the nine schemes were compared and analyzed, and the optimal scheme was eventually determined as scheme 9. The method proposed in this paper provides a new concept for the structural optimization design of a large mining headframe, and it has great significance for restraining the resonance phenomenon and ensuring the safety of mining operations.
... It is especially important to use tilt monitoring systems in conditions of instability of soil foundation, or in the case of high and non-uniform external loads associated with different natural factors, weather events or the operation of technological equipment. Works [9][10][11] describe the application of the systems for controlling the inclination of the shaft head when extracting ore from the mine. ...
The paper presents a block diagram of an automated inclinometer-based system for monitoring the inclination of a high-rise metal structure of the shaft headframe. The stress-strain state of this structure is defined by the loads associated with the operation of shaft skip and the impact of the environmental factors on the structure. The data obtained by 6 inclinometers located at different height were used to determine the inclination of the headframe and distortion of its shape. Analysis of long-term observation data revealed the existence of deformation processes having different time scales (long-term, seasonal and daily). A correlation between changes in the tilt angle of the structure and ambient temperature was established. Long-term monitoring of tilt angle showed that the displacements of the structure were within the permissible limiting values. The developed monitoring system is of great theoretical importance for understanding the deformation processes arising during the operation of such structures.
... China has one of the richest coal reserves in the world. According to incomplete statistics, China's proven coal reserves are about 1 trillion tons, with complete coal types and wide distribution areas, which provides a reliable material guarantee for the development of the coal industry [1][2][3][4][5]. With the mining of mineral resources gradually shifting to the deep, the proportion of large diameter (more than 8 m) and deep shaft (more than 1000 m) exploitation will be further increased. ...
Based on the newly developed sinking headframe for the deep and large shaft, the finite element model of the full-scale headframe was established by using SAP2000. Through the calculation, the theoretical stress of the headframe at sinking depths of 40 m, 143 m, 223 m, 518 m, 762 m, 1000 m, 1250 m, and 1503 m was obtained and then compared with the field measured stress. The results show that with the increase of shaft sinking depth, the theoretical stress of finite element simulation and the field measured stress of each member of the sheave wheel platform and the headframe increase linearly, and for the maximum member stress in the upper, middle, and lower layers of the headframe, the numerical simulation value is greater than the field measured value and less than the designed steel strength. In other words, under normal working conditions, headframe members are in the elastic stress stage and meet the design requirements, and instability failure of headframe members will not occur. The end-restraint mode of the supporting bars has a great influence on the force of the top member. The reasonable selection of the restraint mode in the simulation is the key to the accuracy of the calculation results. The simulation results well reflect the actual stress of the headframe and provide a reliable guarantee for the follow-up work of the project.
... Therefore, restraining the headframe resonance in a large hoist system is critical for reducing shock and vibrations, thereby maintaining the safety and reliability of the mining equipment. In recent years, although many studies have investigated large hoist systems, including hoisting rope vibration analyses, 1-9 head sheave failure analyses, [10][11][12][13] headframe designs, [14][15][16] and headframe life estimation, 17 no studies on restraining the headframe resonance in large hoist systems have been reported. ...
Headframe resonance is a major cause of large hoist system damage and instability. Therefore, restraining the resonance of a large hoist system headframe is critical for reducing shock and vibrations, thereby maintaining the safety and reliability of the mining equipment. In this study, an approach was developed to restrain the resonance of a large hoist system headframe. A finite element model of a large hoist system headframe was established. Simulations were carried out, and the modal characteristics of the large hoist system headframe were obtained. The results showed that the second- and third-order natural frequencies were both close to 1.5Hz. Furthermore, experiments were conducted. An analysis of the experimental and simulation results indicated that a vibrational forcing with a frequency of 1.56Hz was a key factor causing resonance of the large hoist system headframe. Moreover, 14 different retrofitting approaches were proposed to change the natural frequencies of the large hoist system headframe, thereby providing resonance restraint. The main retrofitting concept is to add new assembled steel box structures with inner stiffeners between the transverse beams and oblique brackets in the middle area of the large hoist system headframe. In addition, the weight added by the retrofitting approach should be minimized to reduce the construction difficulties and costs. After a comprehensive comparison, an optimal retrofitting design of the 14 retrofitting approaches considered was selected. This optimal retrofitting approach provides guidance for restraining the resonance of large hoist system headframes. Furthermore, this study provides a method for the design of large hoist system headframes and the determination of the vibration characteristics.
