基于脉冲激光加载的复杂微构件冲击液压微成形基础研究

针对现有微成形难以制造具有凸台、加强筋等细微特征的复杂微构件难题，提出以脉冲激光能量作为冲击源，液体作为传力介质进行冲击液压微成形的新方法。基于冲击动力学理论与自建测量系统，建立激光冲击液压微成形液体冲击波加载工件的压力模型；基于流-固耦合有限元分析，探明液体动态成形冲击波的传播、加载与变形成形机理，揭示液体介质对冲击波压力的均压效果，及其对微成形能力、精度和质量的影响规律，为激光冲击能量预测液体冲击波压力并控制成形压力提供理论基础；基于实验研究激光加载冲击液压微成形工件的微观组织演变规律及失效形式，揭示微成形中工件的高应变率塑性变形机理及失效机理，探明激光冲击液体高应变率增塑行为对尺寸效应的抑制程度，并建立微塑性成形工艺的基础数据与工艺准则，为微构件成形成性一体化控制奠定基础。相关内容涉及众多全新科学问题，研究成果可以丰富和发展微成形理论，并对复杂微构件的工程化制造提供理论支撑。

In view of the difficulties in manufacturing complicated micro-component with fine features such as bosses, ribs and small fillet using the existing microforming technology, this project proposes a new impact hydroforming method which employs pulsed laser energy as the impact source and liquid as the force transmitting medium. Based on the impact dynamics theory and Self-built measurement system， the pressure model of shock waves loading on workpiece in pulse laser impact hydroforming is established. Based on the finite element analysis of the fluid-solid interaction(FSI), the propagation, loading and deformation mechanism of shock wave formed by dynamic liquid are proved. The homogenization effect of liquid on shock wave pressure and its influence on microforming ability, precision and quality are revealed, which provides theoretical basis for prediction of shock wave pressure of liquid and control forming pressure in the terms of laser energy. Based on the experimental study, the microstructure evolution and failure mode of the workpiece under dynamic loading of laser impact liquid is studied to reveal the high strain rate plastic deformation mechanism and failure mechanism of workpiece in microforming. And the degree of suppression of size effect under high strain rate plasticizing behavior of laser shock liquid is revealed. The basic data and process criteria of the micro-plastic forming technology are established, laying the foundation for integrated control of micro-component forming and formability. The related content involves many new scientific issues, and the research results can enrich and develop the microforming theory as well as provide theoretical support for the engineering manufacturing of complicated micro-components.