Structural Design And Dynamic Analysis Of Jacking Machine With Following Safety Device

Heavy-duty lifting equipment is widely used in mining,construction,bridge and other engineering fields.Its safety performance is the key to design.Aiming at the potential safety hazards of the current hydraulic jacking equipment in actual engineering,a jacking machine with following safety device was designed.The finite element analysis technology was used to analyze the impact dynamics and modal characteristics of the designed jacking machine.Based on the modal analysis,the structure was improved.Finally,the manufacture and debugging of the principle prototype was completed and the operation was carried out.The main contents and results are as follows:(1)The structural design scheme of the jacking machine was proposed.The design and calculation of the load-bearing components were completed.Based on the overall design scheme,the transmission design scheme of the safety device was determined and the design and calculation of the transmission system were completed.According to the design results,the 3D modeling and assembly of each component of the jacking machine were completed.(2)According to the working principle of the jacking machine with following safety device,the hydraulic cylinder may fail during the lifting process,and the heavy object may fall and impact the safety device.The finite element analysis software ANSYS/LS-DYNA was used to analyze the impact dynamics of the safety device.The influence rule of the drop distance of the heavy object on the stability of the screw assembly was obtained through analysis.The dynamic response characteristics and the dynamic buckling morphology of the screw assembly under the impact were obtained.The maximum drop distance of the heavy object that the screw assembly could withstand was obtained.The overall stability of the safety device and the strength of key components when the heavy object dropped at this distance were verified.The rationality of the maximum drop distance of the heavy object was analyzed.It provides a basis for the following control of the jacking machine.(3)Aiming at the situation that the resonance may affect the stability of the structure during the operation of the jacking machine,a modal analysis was performed on the jacking machine,and the natural frequencies and modal shapes of different strokes in two working states of the jacking machine were obtained.According to the natural frequency,it was judged whether the structure will resonate with the impact frequency of the heavy object and the power of the jacking machine itself.According to the the modal shapes,the shortcomings of the structure were analyzed,the design of the jacking machine was improved.Harmonic response analysis was performed on the jacking machine before and after the improvement,and the response values of the jacking machine when resonance occurred were obtained,which verified the effect of the improved design.(4)In order to verify the feasibility of the drive system and follow-up protection function of the safety device of the jacking machine,completed the design,manufacture and assembly of the principle prototype,and debugged the prototype to achieve the expected working goals.