Research On System Dynamics Modeling Method And Application Of Hoistman-Crane-Rail/Temperature System

The casting crane is a kind of metallurgical mechanical equipments with high energy accumulation and dangerous operation,which realizes the vertical lifting and horizontal movement of ladle through the combination of working mechanism.With the progress of technology and the expansion of the city,industrial bases have been built in the form of land reclamation in ports of coastal areas.This leads to the phenomenon of foundation sinking and rail defects increasing in crane workshops,which leads to the cracking of the metal structure and the strong vibration of the driver.The working environment of casting cranes is very terrible.High temperature,high humidity,high dust and rail defects have a great influence on the mechanical properties of metal structural,which accelerates the destruction of the metal structure of the casting crane,reduces the service life of the crane,affects the health of the driver and even endanger the lives of workers.The current research does not take into account the dynamic characteristics and safety of the crane under the circumstance of the above circumstance,nor does it involve the analysis of human vibration comfort under the orbit defect.For this reason,this article carries out the following research from the perspective of the human-crane-environment system:1.Aimed at the influence of rail defect of crane operation on impact coefficient,this article puts forward to mathematical model of rail defects by cosine function simulation and dynamic model of crane operation process passing the rail defect.Based on the theoretical derivation,the expression of the impact coefficient of the crane operation under step defects and gap defects is obtained.Compared with GB/T 3811-2008 and ISO 8686-1:2012,the feasibility of derivation results in this paper is verified.Based on the structural parameters of the crane and the characteristics of the rail defects,the critical conditions for the coupling effect between step defects and gap defects and the impact process of the four wheel sets of the crane through the rail defects are analyzed.The strain time course of the dangerous point for the metal structure is measured through the experiment,when the cart runs through the rail defects under full load.The impact coefficient of theory solved in this chapter is applied to the finite element model for calculating the maximum stress value of the measurement point under the maximum impact load.By comparing the results of the finite element model with experimental test results combined Hooke law,the correctness of the theoretical derivation of the operational impact coefficient is verified.2.A dynamic optimization design method based on the dynamics of the hoistman-crane-rail system and annoyance rate is proposed in order to study the structural vibration characteristics under rail defects and driver comfort during the operation.Based on the standard of human vibration evaluation(ISO 2631-1:2011),the human body vibration comfort was quantitatively evaluated by using the annoyance rate model.A dynamic optimization design model of crane structure based on particle swarm(PSO)algorithm and human vibration annoyance rate is constructed,and the optimal design parameters of crane structure satisfying human vibration comfort are obtained.It provides theoretical basis and parameter basis for design,analysis and dynamic response of human body parts.3.Aiming at the problem of fatigue damage in various parts of human body,the dynamic response and analysis methods of human body parts based on precise integration method are proposed.Based on the biomechanics of human body,the system dynamics model of seven-degree-of-freedom body vibration model coupled with crane-rail model is built.A system motion equation based on Lagrange equation is established,and the vibration response of each part of human body is solved by the fine integral method.By comparing the calculation results with the existing fatigue damage standards of various parts of the human body,the damage conditions and vibration comfort of each part are analyzed and seat parameters and effect of nonlinear factors on the different parts of the body vibration are explored.4.Aimed at the dynamic response of the main beam and the cab during the operation of the crane trolley,and based on the crane structural characteristics and the system dynamics principle,the coupling system vibration model of the flexible main girder,cab,trolley and hoisting is established.The modal function of the main beam is obtained by the mode superposition method.Combined with the Lagrange equation,the vibration equation of the system is established.The direct integration method(Newmark method)is applied to solve the approximate solution of the vibration of the nonlinear system,and the dynamic response of the main girder and the hoisting is obtained during the operation of the trolley.By analyzing the effect of cab properties and connecting parameters on the vibration of the main beam and the cab,the changing rules of the main girder and hoisting angular viration are discussed under different parameters.The model can provide a theoretical basis for the design and dynamic analysis of crane girder during operation.5.In order to research the influence of temperature field on mechanical properties of crane metal structure,the elastic modulus of Q345 steel under different temperatures was tested by using metal elastic modulus test bench.The constitutive equation of elastic modulus in different temperature is predicted by neural network algorithm.The dynamic characteristics and service safety of crane main girder and cab under different temperatures are analyzed by using the trolley operation system dynamics model and the elastic modulus constitutive equation under the action of temperature field.