精锻叶片模具三维型面优化技术

3D Die Shape Optimization Technology for Net-Shape Forging of Aerofoil Blade

基于有限元模拟技术,对包括切边工序在内的叶片精锻过程进行了准确模拟,并针对叶片锻造过程中叶身型面产生的尺寸偏差,采用模具型面直接补偿的方法对叶片精锻模具进行了三维优化设计.通过模拟,定量给出了锻件型面的尺寸偏差,建立了偏差类型与型面变形之间的关系.以锻件型面偏差总量最小为优化目标,设计了基于变化的权重优化算法,准确计算了模具型面各节点上的插补值,并利用B样条曲面构建技术对优化后的模具型面进行了重构.开发了模具型面直接补偿优化设计系统,并对镍基叶片模具进行了优化设计.结果表明,模具型面偏差明显减小,优化效果显著.

A precise simulation for net-shape forging process of aerofoil blade including flash trimming operation was investigated and a direct surface compensation method for 3D optimization design of die shapes was proposed in terms of dimensional and shape tolerances of aerofoil cross-sections emergence during forging process.Quantitative representations of aerofoil forging tolerances were established to provide a correlation between conventional dimensional and shape specifications in forging production and those quantified in FE simulation.A new algorithm employing variable weighting factors to minimize the total forging tolerances in forging optimization computations was proposed to calculate compensation quantities of die surface nodes.A surface approximation using a B-spline surface was also developed to ensure improved die surface quality for die shape representation and design.For a Ni-alloy blade test case,substantial reduction in dimensional and shape tolerances was achieved using the developed die shape optimization system.