Stress Monitoring Of Gantry Crane Jib System

As the operation special equipment,gantry crane is widely used at the port.The structure safety of the jib system which is the important component of gantry crane directly affects the production safety of the port.In view of many accidents happened on the domestic port with arm of gantry crane broken suddenly,structure analytical software ANSYS was uesd to bulid the finite element model of portal crane with the M10-30 type of portal crane.The stress,deformation and fatigue life of the the jib system are analysed and calculated,to find out the critical parts of greater equivalent stress and easy to crack initiation.By using fiber grating sensors,intelligent signal collection and processing system of type INV306,and the stress monitoring software based on LabVIEW,the variation of the key parts' stresses of jib system is monitored actually under different working conditions.The testing data including static strain values and dynamic strain curves of jib system were compared with the analysis results of the finite element model.The results show that in the jib system of M10-30 portal crane,the maximum displacement is located in the the lifting point and the value is about 117mm.Relating to other parts of the jib system,the whole cantilever has a larger displacement.The results of stress analyses indicate that the top of the cantilever,the bottom of the tie rod,the tripod of the jib and the bottom of the derrick appear the greater equivalent stress.The fatigue life simulation analysis indicate that the fatigue life of the weakest position in jib system is on the connection of lifting point front limb listrium and jib upper limb listrium.Under different conditions,the jib lifting point is the most higher stress part,which is main monitoring.Under static conditions,except for the surface position of the jib's tipod,for the positions of higher stress,such as the cantilever,the bottom of the tie rod and the bottom of the derrick have a approximate result of the maximum equivalent stress with finite element simulation.On surface position of the jib's tipod,the maximum equivalent stress and simulation results have a lower absolute deviation,but their relative deviation is higher,which is due to the factors of simplified finite element model load location,grid numbers and the counterweight etc.The results of dynamic load test indicate that,under metabolic conditions,the maximum stress value of the jib system of gantry crane is located in the cantilever;while under rotating conditions,the bottom of the tie rod bears disturbed stress of much more frequency and amplitude,which is easy to produce fatigue damage.In the actual using,it is necessary to focus on monitoring the changes of the alternating stress values of these parts,as well as provide some scientific references for the stable operation,daily management,and maintenance of gantry crane by relevant data analyses.