大弯扭叶片热模压成形有限元模拟及其预制坯的优化设计

Finite element simulation of hot die forming and optimization design of preform for a blade with large-angle crankle

采用有限元方法进行了大弯扭叶片热模压成形工艺的数值模拟,并利用模拟结果实现了成形叶片的反向展开,完成了叶片热模压成形的平板预制坯的优化设计,研究并将该方法所得到的展开平板坯与几何展开法和机械压平法的结果进行了对比.研究发现,传统展开方法得到的结果与有限元模拟法得到的结果相差很大,有限元方法考虑了实际成形中温度场的变化、工件定位方式、塑性变形过程,可以得到定位准确、周边余量很小且分布均匀、压形后贴模情况优良的平板预制坯,与目前常见的几何展开法和机械压平法相比取得了显著进步.实验结果表明,采用有限元法设计的预制坯可直接用于生产,无需反复调试,节约了材料,提高了生产效率.

The hot die forming of blades with large-angle crankle is simulated by finite element method,and the unbending of the blade is realized applying the simulation results so that the optimized design of flat preform for this process is executed.Moreover,the flat preform designed by the op timization is compared with those from geometry unbending and mechanical flattening,illustrating that the results from tradition al unbending methods are obviously different from the finite element method.In finite ele ment method,the temperature field,the workpiece position ing and the plastic deforma tion during the practical process are considered,so that a flat preform accu rately positioned,with small and uniform allowance and good die con tact state,can be designed.Therefore,a notable progress is made compared with the well-known geom etry unbend and mechanical flattening.In addition,from experiments,it is proved that the preform designed by the finite element method can be used in production directly with out trials and errors,re sulting in saving material consumption and enhancing productivity.