The structural health monitoring of the casting crane is to evaluate the safety degree or health status of the metal structure as a whole and key parts by means of on-site inspection and testing or by means of installing sensors to remotely transmit test signals. It is a safety assessment of the structural bearing capacity, and also includes the risk assessment and estimation of the service life of structural members after long-term use of strength damage accumulation, The analysis results will prompt the user to know the safe service life or update time point of the equipment. The main indicators of structural health monitoring are shown in the table.
Indicator Type | Index content | Detection means | Significance |
Strength evaluation | Maximum stress of main beam, maximum shear stress of main beam | Field test or remote monitoring | Stress increases at the end of service life |
Stiffness evaluation | Upper camber, horizontal bending and lower deflection of main beam | On site inspection | Obvious attenuation in late life |
Dynamic stiffness evaluation | Dynamic stiffness of the whole machine | Field test or remote monitoring | Obvious attenuation in late life |
Stability evaluation | Web waviness, vertical deflection and horizontal deflection of upper cover plate | On site inspection | Long term stability of indicators before structural failure |
Fatigue evaluation | Fatigue life estimation of main beam | Field test or remote monitoring | Monitoring the change of stress spectrum |
Metal cracking | Welds and base metal of main beam, end beam and wheel seat | NDT or visual inspection under strong light | Regularly burst in groups at the end of life |
Among the main indicators of structural health monitoring, the change of dynamic stiffness index is a data that is easy to be ignored. Current engineering examples show that the change of dynamic stiffness index is related to structural risk, and the decline of dynamic stiffness indicates the rise of structural risk.