Design Of Condition Monitoring And Fatigue Life Prediction System For Crane

As handling equipments, cranes are widely used in ports, construction sites and other places, and play an irreplaceable role in national production. With increasingly wide use of crane, the risk of crane accidents is also increasing, which will cause irreparable casualties and property losses. Therefore, a monitoring system of crane operating status based on strain and inclination is designed, and its timely on-line monitoring of operating status can achieve performance evaluation of crane.Firstly, current development of crane safety monitoring system domestic and abroad is analyzed, and fatigue life and deflection are chosen as the major performance evaluations. Estimating remaining life of crane effectively and reliably can ensure crane run safely, which will make full use of crane. As for gantry crane, deflection is an important indicator of the deformation for main beam. Monitoring deflection can ensure safe running of the little car, and provide the basis for maintenance of the main beam.Secondly, according to the technical requirements of the crane condition monitoring system, program of data remote transmission is determined. Serial port to 3G is chosen as the data transmission medium. Data is transmitted to 3G module from the microcontroller via serial port. Then 3G module transfers data to remote monitoring terminal via TCP/IP protocol, and ultimately the network oriented remote monitoring can be realized.Then, the functional requirements of crane monitoring system are studied, combining with sensing technology, embedded technology and wireless communication technology, double-level safety monitoring system of crane is built, whose above is remote monitoring system and the bottom is sensor node. Design of hardware and control software is finished, which includes sensor, microcontroller and peripheral circuit, power,3G module and remote server. Remote server needs to complete the analysis, display and save of data, and also evaluate the operating status of crane by using methods of safety evaluation, and finally the intelligent monitoring of crane can be accomplished.And, fatigue life estimation and deflection monitoring of crane achieve successfully. Stress-time history is processed by rain-flow counting to obtain a two-dimensional metal structure stress spectrum, which provides basic data for fatigue life assessment. By analyzing deficiencies of the prior cumulative damage theory, the linear cumulative damage theory based on modified coefficient is proposed. And by comparing the testing results, the theory after correction is found more accurate. A model of simply supported beam is established and the circumstance with loading of combined loads is studied to get the deflection curve equation. Then the basic method for calculating deflection from angle is introduced.Finally, tests in laboratory and on the site are finished to verify the stability and effectiveness of the system.