激光选区熔化菱形正十二面体点阵材料的承载与失效特性

Research on bearing and disable properties of laser selective melting rhombohedral dodecahedral lattice materials

为了探索液体火箭发动机轻量化方法,充分发挥增材制造技术优势,基于激光选区熔化成形技术制备了不同微桁架直径的周期性菱形十二面体多孔点阵材料,借助扫描电镜观察并测量了其微桁架结构,对相对致密度、压缩特性进行了表征,建立了相对致密度的预测模型,得到了相对弹性模量、相对抗压强度与相对致密度的函数关系,结合应力-应变曲线、压缩过程影像和断口金相,分析了点阵材料压缩过程中的失效行为和机理。研究成果应用于某型动力装置总装支板、某型发动机新型换热器的轻量化设计,经受了拉伸和压缩载荷下的液/气压试验。

In order to explore the lightening method of liquid rocket engine and make full use of the advantages of additive manufacturing technology,periodic rhombohedral dodecahedral lattice materials with different micro-truss diameters based on laser selective melting forming technology were prepared.The micro-truss structures were observed and measured by scanning electron microscopy.The micro-truss structure was characterized by relative density and compression characteristics.The relative density prediction model was established.The function relationship between the relative elastic modulus,relative compressive strength and relative density were obtained.Combined with stress-strain curve,compression process image and fractograph observation,the failure behavior and mechanism of the lattice material during compression were analyzed.The research results were applied to the lightweight design of the main assembly plate of a power plant and the new heat exchanger of a certain type of engine.It was subjected to the liquid/air pressure test under tensile and compressive loads,and finally its further application in liquid rocket engines was prospected.