The Development Of The Mechanical Analysis System Of Excavator Working Device And The Compilation Of Bucket Rod Load Spectrum

With the construction projects increasing, the excavator plays an important role in the building construction due to the characteristics of high efficiency and wide application range.Though the excavator has been widely used, its damage has got large number of attention. In those damages, the fatigue damage occupies a large percentage. In order to research the fatigue of bucket rod, the history of outside load becomes much critical. On account of the bad work conditions, it’s hard to install sensor at the bucket tip to achieve load directly. In this thesis, by measuring the stress of boom section obtains the load history indirectly, the initial data is provided for studying the fatigue life of bucket rod. The main research of the thesis includes:(1) The author analyzes the movement relationship of the excavator working device in detail, establishes the movement equations of joints in working device with the cylinders of the boom, bucket rod and bucket. Based on the load of bucket tip, the forces loaded on the hinge points are obtained. Then combining with the boom structure, the calculation model of the bucket tip load by the section stress of boom is established. It lays the theoretical foundation for calculating the bucket tip load with the measured stress data.(2) With the theory of stress testing and the structure of boom, the author researches the load-time of the bucket rod based on boom stress testing, selects the suitable stress measure section and makes the appropriate section stress measuring plan. Then the measuring plan is checked by the load experiment at the bucket tip.(3) Based on the measured stress data, the bucket tip loading-time is calculated, further to loading-time of the bucket rod. The bucket tip loading-time is divided into several parts.Last through the algorithm of rain flow counting, the bucket rod load spectrum has been compiled.(4) Considering the large amount of measured data, the working device analysis system is programmed through VB software. The system can do the moving relationship and joints’ load analysis, boom stress calculating and obtaining the bucket load. It’s convenient that the working device analysis system is used to calculate the bucket tip load. Later, the calculation result is verified with the ANSYS simulation.After the analyzing the measurement methods of the bucket tip load-time, the working device analysis system for the purpose of the measured data dealing is developed. The bucket rod load spectrum is compiled. The research results can be used to obtain the bucket rod load spectrum quickly and efficiently. It’s convenient to predict the fatigue life of the bucket rod.