Research And Application Of Metal Core Bar Optimization Method Based On Topology Optimization In Sand Casting

In the casting production process,the sand mold requirements on strength,collapsibility and gas generation are different.Metal core bars can enhance the permeability and collapsibility of sand core,improve the core strength,and meet the diversified needs of complex casting core.However,the traditional design method of metal core bar is simple and mainly relies on artificial experience.Especially in the complex mold core,the distribution of metal core bar materials is lack of theoretical guidance and scientific basis.Topology optimization is a method to find the optimal material distribution under the premise of mechanical properties.Therefore,this paper proposes an optimization method of metal core bars in sand casting based on topology optimization.Firstly,the SIMP topology optimization model is used to optimize the metal core bar.This paper studies the mathematical model and the OC solution method,and adopts the grid filtering method to solve the numerical problems such as checkerboard in the topology optimization results.Based on the above work,the topology optimization program is completed with C++ language.Secondly,the topology optimization program is used to optimize the metal core bars which are applied to the sand cores.These sand cores are used in the bending,compressive and tensile strength experiments to research the sand cores change with different metal core bars.The experimental results show that the strength of sand core has no change before and after optimization,and the optimized metal core bar structure meets the strength requirements of sand core.Compared with the common shape core bar,the optimized core bar mass can be reduced by more than 59.9%.Finally,the structure of the metal core bar is optimized in a crown casting.The casting numerical simulation method was used to obtain the stress conditions of the metal core bars,which were used in the topology optimization of the metal core bars.Then the metal core bars were optimized one by one.Finally,the optimized metal core bars were applied to the actual production.The pouring process and the quality of the product show that the optimized metal core bar structure can meet the requirements of the sand core strength of the crown casting.