Analytical And Experimental Study On The Shredding Processes Of Discard Vehicle Light Steel Scrap Based On Virtual Manufacturing Technology

This dissertation aims at having a profound study of the shredding process and the theory of discard vehicle light steel scrap, at improving the traditional researching method and level of shredding process of discard vehicle light steel scrap, at obtaining the sensitive factors that affect shredding efficacies, at evaluating and estimating the property and quality of shredding system, at optimizing and improving the shredder, at predicting the machining technological process, manufacturing and assembling of shredder, and at providing a digital engineering platform for the studies of the shredding system of discard vehicle light steel plate. Some fundamental analytical and experimental studies are carried out to achieve further researching results on shredder and shredding processes of discard vehicle light steel scrap. The theories and simulating methods that are proved feasible in shredding tests and simulation of steel scrap are acquired.The utilization of Metal Recycling Resource in an effective way can reduce exploitation and depletion of Natural Mineral Resource and Metal Resource, occupation of land, consumption of energy, investment; can prevent the pollution of the environment, protect ecosystem and can improve productivity. Because of a shortage of Natural Mineral Resource, Metal Recycling Resource is playing an important role in the development of the world economy. Now so a large number of countries are positively and effectively reclaiming and utilizing Metal Recycling Resource that they can control the over-consumption of Natural Resource and waste of Energy Resource. On the other hand, with the development of our national economy and improvement of people's life level, their concept, structure and level of consumption are changing. More and more automobiles and other electric equipments are being used by average families. In order to reclaiming and utilizing potential steel scrap of these products in 10-20 years and enhancing the level of mechanization to recycle them, it is very significative to study foreseeingly the shredding mechanism of steel scrap and shredder.From the establishment of geometric model, kinetic model, dynamic model and finite element model of the shredding process of discard vehicle light steel scrap, the relative position, movement, forces and reacting forces of shredding tool and steel scrap are carefully studied. The geometric nonlinear, material nonlinear and contact nonlinear in shredding process of light steel scrap are thoroughly researched. The simulating method of digital algorithm is analytically studied.In order to finishing the shredding test of discard car light steel scrap, by means of the virtual prototype of "58.84/29.42 Joule Standard Material Impact Test Machine" the original machine is improved. The mass, shredding velocity and impact energy of shredding tool are exactly calculated. The shredding test of light steel scrap of two types discard car are carried out on the improved Impact Test Machine. A great number of experimental data are acquired.The experimental shredding processes of discard car light steel scrap are simulated by means of FEM software ANSYS/LS-DYNA based on nonlinear finite element method. Through making a comparison between experimental data and simulating results the simulating model and method of shredding processes of discard car light steel scrap are improved and perfected. A series of reliable means of building finite element models, scientific principles of defining element types (include real constants and calculating formulae) and assigning element attributes, effective rules of meshing solid model and controlling mesh (such factors as the element shape, midside node placement, and element size to be used in meshing the solid model), basic measures of describing contact interface and their parameters, practicable methods of applying loads and initial conditions of the shredding process of discard car light steel scrap are acquired. The properties of hourglassing mode and base vectors are investigated, and the controlling means of hourglassing mode are obtained. The researches have show: the results of experimental and analytical studies of the shredding process of discard car light steel scrap are almost similar so that simulating ways of the experimental shredding processes of discard car light steel scrap can be applied to the studies of other shredding processes of discard vehicle light steel scrap.According to the methods of simulation and results of experimental processes that two types discard car light steel scrap are shredded, the shredding processes ofΠsection steel of truck main beam, multi layer light steel plate in box and thin steel plate box with windows are largely simulated. The shredding efficacies that alteration of the positions of impact points, the length of arm, the diameter of shredding hammer's forepart knob, the velocity of shredding hammer, the thickness of the light steel scrap, the material property of light steel scrap, the mass of impact hammer and the deposited positions of steel scrap affect are thorough and carefully studied, and the corresponding results are acquired, and the sensitive factors that affect shredding efficacies are obtained. The researches to the discard vehicle light steel scrap have showed: the more the impact energy of shredding tool is and the smaller the diameter of shredding hammer's forepart knob is, the better the shredding efficacies are and the bigger the area that steel scraps are penetrated and torn to pieces is. With increase of the distance between impact points and bearing side, the flexibility of the steel scrap frames raise, the sustaining stiffness decrease, and the steel scrap generates yield and escape to shredding hammer, these lead to the shredding ability of impact hammer goes down. In the process that thickness of the discard car light steel plate becomes thin, although the penetrating and tearing energy that they absorb reduces, the drop of steel scrap frames' stiffness brings about that area that steel scraps are penetrated and torn to piece becomes from large to small. In a word the remarkable factor that influence the shredding efficacies of discard vehicle light steel scrap are the velocity of shredding hammer, the distance between impact points and supporting side, the diameter of shredding hammer's forepart knob. The mass of impact hammer, the length of arm, the material property and the deposited positions of steel scrap are secondary factors, their effect to shredding efficacies of the discard vehicle light steel scrap is not quiet obvious.On the basis of the results of simulating studies of processes in which discard vehicle light steel scraps are shredded, by means of virtual prototype technology, all digital parts of discard vehicle light steel scraps shredding system are virtually manufactured, and all digital parts can be used in follow-up simulating studies. Through the assembling of all digital parts, virtual digital prototype of the shredding system is acquired in computer. The checking for interference between parts in the shredder assembly, the evaluating and estimating to the property and quality of shredding system, the kinetic simulating of shredding tool and steel scrap, optimizing and improving of shredder are carried out on virtual digital prototype of the shredding system. By way of virtual prototype, the cooperating mechanical and electrical mechanism, machining technological process, mechanical properties, manufacturing and assembling, checking of quality, the managements of manufacturing processes of the shredding system are analyzed and predicted, and digital engineering platform is provided in recycling life period (design, research, machining, manufacture, assemble, sale, reclaim, utilization, prediction of shredding processes) of the shredding system of discard vehicle light steel plate.