基于激光原位预热的连续纤维增材制造层间强化机理研究

Investigation on the Interlaminar Strengthening Mechanism of Continuous Fiber Additive Manufacturing Based on Laser In-situ Preheating

连续纤维复合材料增材制造具有成形自由度高、材料利用率高、模具依赖度低等优点,能够实现复合材料的快速低成本一体化制造,满足航空航天等领域复材构件短周期高性能的成形需求。但基于层层堆积成形原理的连续纤维复合材料制件层间性能较差,在长期使役过程中极易出现分层失效,严重限制其广泛应用。本研究提出了基于激光原位预热的连续纤维增材制造成形方法,通过建立基于“生死单元”技术的有限元仿真模型,揭示了激光预热对增材制造成形温度分布及其演变规律,并通过实验验证了其对改善成形制件层间性能的有效性,最终获得了激光预热的层间强化机理。结果表明,激光预热能够快速加热样件表面温度,促进层间树脂的熔合粘接,并进一步促进成形丝材的重熔浸渍,相较于未经预热样件,激光预热后层间剪切强度最大提升115%。

Continuous fiber reinforced composites additive manufacturing has the advantages of high forming freedom,high material utilization rate and low die dependency,which can realize the rapid and low-cost integrated manufacturing of composite materials and satisfy the short-cycle and high-performance forming requirements in aerospace and other fields.However,the layer-by-layer stacking form leads to poor interlaminar performance,which easily induces delamination in the long-term service and seriously limits its wide application.In this study,a continuous fiber additive manufacturing forming method based on laser in-situ preheating is proposed.By establishing a finite element simulation model based on the"life and death element"technology,the temperature distribution and evolution on additive manufacturing are revealed,and its effective performance on improving the interlaminar performance of formed parts is verified through experiments.Finally,the interlaminar strengthening mechanism of laser preheating is obtained.The results show that laser preheating can rapidly heat the surface and internal temperature of the sample,promote the bonding of resin between layers and the remelting and impregnation of internal wire materials.Compared with the sample without preheating,the interlaminar shear strength of the preheated sample is increased up to 115%.