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根据应用耗散结构理论和人工神经网络确定的热力参数稳定区以及晶粒度演化的状态空间模型,应用最优控制理论确定保证获得要求组织的GH4169合金的最优轨迹,即热力参数随时间的变化规律,以便获得晶粒细小的GH4169合金锻件。通过变分法根据有限元数值模拟结果和材料最优轨迹优化等温锻造用液压机滑块速度随行程变化曲线,使工件内热力参数变化接近材料最优轨迹,以获得优质的GH4169合金锻件。计算结果表明,本文提供的方法可有效控制等温锻造过程中工件内热力参数的变化,从而优化锻件的显微组织。
According to the steady state of thermal parameters and the state space model of grain size evolution determined by dissipative structure theory and artificial neural network, optimal control theory is used to determine the optimal trajectory of GH4169 alloy which is guaranteed to obtain the required structure, that is, the thermal parameters over time The law of variation, in order to obtain fine grain GH4169 alloy forgings. Through the variational method and the optimum trajectory of the material, the variational method is used to optimize the speed curve of the slider of the isothermal forging with the curve of the stroke, so that the thermal parameter in the workpiece changes close to the optimal trajectory of the material to obtain the high quality GH4169 alloy forging. The calculation results show that the method provided in this paper can effectively control the variation of thermal parameters in the workpiece during the isothermal forging process so as to optimize the microstructure of the forging.