Study On The Deformation Of Extrusion Container And Structure Optimization

The large thin-walled parts have been widely used in the industry and daily life dueto its high strength ratio and reliability. The optimization design of extrusion die andcontainer will have direct impacts on the quality of the finally product. It’s required forboth of container and die due to the thin wall, lager dimensions, lager width/height ratio,shape complexity and high precision of the product. Existed studies shows that it willproduce high quality of large thin-walled parts when use the flat extrusion container.The deformation and stress of the container will be studied in this thesis. The analyticalmethod and numerical simulation have been used to analysis the stress and strain of theextrusion container for various working conditions, and the structure of extrusioncontainer is then optimized. These studies will provide a new design method forextrusion container to improve quality of the product and the reliability of the container.The mainly works of this research are:①For solving the problem of complex formula and complicated calculation, whenwe use stress superposition method to calculate multi-layer extrusion container. Basedon the theory of thick-wall cylinder, this thesis deduces displacement coordinationmethod to study contact stress between the layers when multi-layer container isassembled under shrink-fitting. The stress and strain are easy to predict by using thisnew model, especially for the multi-layer container.②The multi-layer extrusion container is analyzed by using the large-scale finiteelement analysis software under preloaded, preloaded-internal pressure andheat-preloaded-internal pressure conditions. The results show that stress concentration isalways existed in the calculation of flat container seriously. The maximum stress can bereduced in the heat-preloaded-internal pressure state. The results of the finite elementmethod are always consistent with displacement coordination method.③This thesis also studies the stress distribution when multi-layer extrusioncontainer is influenced by the different interference fit and the different shapes ofinternal lay of container. When the strength of extrusion container is smaller thanoriginal one’s, then determine the best area of shrink-fitting distribution. Studies showthat the shape of container is constituted by line with elliptical arc, the value of stressconcentration is lessened and the location will transfer comparison with other shapes ofcontainer. ④Combining with object-oriented C#, the large-scale finite element software, theparametric of Python and MATLAB optimization tools, to establish the structure modelof multi-layer flat extrusion container. The minimum value of stress is set as objectivefunction. The shape of straight line with circular arc and the shape of straight line withelliptical arc are mainly used as the research objects. The purpose is to obtain the bestparameters of the extrusion container’s internal shape.It is believed that the analytical methods and research results in this thesis havesignificant theoretical sense for optimizing the shape of multi-layer extrusion container,improving the stress state of the internal shape of flat extrusion container and extendingthe service life of flat extrusion container.