Research On Mechanical Behavior And Vibration Reduction Of SL6 Shiploader Boom Luffing Winch Platform

Large port bulk shiploaders play an important role in industries such as energy, power, metallurgy, port, etc. especially in the rapid, stable, efficient and cumulative development of some balk cargo collection and distribution center. With the acceleration of economic globalization, new design concepts made the delivered payload capability of shiploaders updating continually, and the structure of the equipment getting larger and larger. Then the stability of equipment, dynamic strength and rigidity of steel structure and vibration performance of the complete appliance has been given more and more attention. Currently, the researches of mechanical properties for shiploaders have mainly concentrated on the aspects of static structure and strength, the study of concerned dynamics behavior for shiploaders are rare in literature. Therefore the researches of dynamic mechanical behavior for shiploaders have important theoretical and engineering significance.Based on the project "Research of boom luffing winch platform vibration for SL6 shiploader in Shenhua Huanghua Port phase II", aiming at the abnormal vibration of boom luffing winch platform of SL6 shiploader in Shenhua Huanghua Port Company, in this dissertation, the spot testing and theoretical researches have been completed, the vibration reduction and reconstruction scheme of platform has been proposed and put into effect. With the reconstructed scheme, the amplitude of vibration has been reduced evidently, and the economic benefit has been increased.Due to large size and dispersive vibration source, the principal vibration source is hard to be fixed. For deciding the principal vibration source of the platform, lumped parameter method was used to establish the nonlinear mathematical model for boom luffing winch system, which considered the nonlinear of winch gear meshing stiffness, and the winch loads under varied velocities of boom luffing have been built model and resolved, which makes the torsional vibration model being consistent with the practical situation. Using variable-step Runge-Kutta method the dynamic response of the nonlinear system has solved, the nature vibration characteristics and responses have been obtained, then to nonlinear response characteristics of torsional vibration system by the spectrum analysis.By establishing FEM models of SL6 shiploader and boom luffing winch platform, the modalities of shiploader and the platform at different boom luffing locations have been calculated. With harmonic response analysis applied to the platform, frequency response characteristics and stress states under different conditions has been obtained. Simulation results and spot testing results confirm each other, which provided a theoretical basis for vibration reduction reconstruction for platform.In order to determine the basic reasons of platform vibration, the dynamic strains of platform and dynamic torques of the gear shaft in boom luffing winch system has been obtained on spot testing, with the modern data technology the signals analysis in time domain and frequency domain have been completed, then the frequency components of platform vibration and torsional vibration of boom luffing winch system have been obtained, the mechanical state of platform in the actual operating conditions have been acquired. The theoretical analysis results accord with that of testing, which proved the simulation model.Based on the spot testing and theoretical analysis, with the consideration of the practical situation, the reasonable and practical vibration reduction scheme has been proposed and put into effect, which enhanced the rigidity of the platform effectively. To assess the effectively of vibration reduction scheme, the reconstruction platform FEM model has been established, and then the strength has been checked. Through modal analysis and harmonic analysis the modalities and the different responses to the level of excitation have been acquired. The contrastive spot testing has been executed, and then the dynamic stress and vibration response results under different conditions have been obtained. By comparing the simulation results and testing results, the rationality and effectiveness of the scheme has been affirmed.In this dissertation, the research methods and solution scheme for the vibration of Huanghua port SL6 shiploader boom luffing winch platform offer a new paradigm for solving vibration problem of similar type of shiploader, and have significance of academic research and engineering reference value.