Research On Fatigue Residual Life Prediction System Of Tower Crane

With the development of China’s national economy and the expansion of infrastructure,tower crane has become the major mechanical equipment during construction. However,severe tower crane accidents have occurred occasionally as a result of fatigue damage which is caused by random alternating stress on tower crane metal structures over a long period of time. Therefore,it is of great significance to develop a system to predict the fatigue residual life of tower crane.In the thesis,the development and existing problems of the tower crane fatigue life prediction is summarized. And on this basis,the rain flow count method for calculating the load spectrum is improved. Besides,a theory model for predicting fatigue and damage of tower crane using Grey Miner principle is put forward specifically. This system could realize the acquisition,transmission and processing of the stress information of the key parts of tower in real time and release the predicted results on a web page so that the user can query and access to relevant information via the Internet anytime and anywhere,which could provide a reliable basis for maintenance of tower crane and therefore is of high engineering practical value.The major work and innovations of this thesis are listed as follows:(1)The structure and load capacity of the tower is analyzed in detail, and the causes of the fatigue damage are explored. By analyzing the different tower crane types,the tower crane fatigue residual life prediction method is proposed and the rain flow count method for calculating the load spectrum is improved.(2) The impact of stress under fatigue limit and loading sequence on fatigue life is analyzed. When the loading stress is from low to high, the tower crane has a greater critical fatigue damage value. When the loading stress is from high to low,the tower crane has a smaller critical fatigue damage value. Based on the above facts, the calculating method of fatigue damage accumulation using Grey Miner principle is put forward and corresponding mathematical model is built so as to predict tower crane life more accurately.(3) The hardware frame structure of ARM development board as core and GPRS module as remote wireless communication interface is designed. And combining the frame structure with multiple sensors used for real-time data acquisition,the field monitoring terminal for tower crane stress is developed. With ASP.NET as development platform and SQL Server2005as database, the system software and algorithm are designed.(4)MATLAB and.NET mix development technology is studied. Life prediction source code is packaged into.NET component through innovative use of NET Builder technology of MATLAB. By calling MATLAB source program through dynamic website business layer,the fatigue residual life prediction of tower crane function is realized.