一种新型激光打印压缩诱导扭转柔顺机构的成型过程和力学变形行为

工程（英文） ›› 2022, Vol. 15 ›› Issue (8) : 133 -142. DOI: 10.1016/j.eng.2021.03.032

研究论文

高捷 ^a^,^b ,
顾冬冬 ^a^,^b ,
马成龙 ^a^,^b ,
戴冬华 ^a^,^b ,
席丽霞 ^a^,^b ,
林开杰 ^a^,^b ,
高彤 ^c^,^d ,
朱继宏 ^c^,^d ,
杜月欣 ^a^,^b

作者信息 +

Formation Process and Mechanical Deformation Behavior of a Novel Laser-Printed Compression-Induced Twisting-Compliant Mechanism

Jie Gao ^a^,^b ,
Dongdong Gu ^a^,^b ,
Chenglong Ma ^a^,^b ,
Donghua Dai ^a^,^b ,
Lixia Xi ^a^,^b ,
Kaijie Lin ^a^,^b ,
Tong Gao ^c^,^d ,
Jihong Zhu ^c^,^d ,
Yuexin Du ^a^,^b

Author information +

文章历史 +

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摘要

本文采用激光粉末床熔融（LPBF）技术成型了一种基于自由约束拓扑（FACT）方法设计的新型压缩诱导扭转（CIT）柔顺机构。研究了LPBF 打印参数对激光打印CIT 柔顺机构成型性和压缩性能的影响。在375~450 W的优化激光功率范围内，样品的致密化水平均保持在98%以上，所获得的LPBF制造的CIT柔顺机构的相对密度随施加激光功率的变化不明显。增加激光功率有利于消除CIT 柔顺机构斜杆内的残余冶金孔隙。在450 W的激光功率下实现了0.2%的最高尺寸精度和20 μm的最低表面粗糙度。LPBF成型CIT柔顺机构的变形行为表现为四个典型阶段：弹性阶段、非均匀塑性变形阶段、强度破坏阶段和变形破坏阶段（或不稳定变形阶段）。采用450 W激光功率最优成形的CIT 柔顺机构在破坏前的累积压缩应变可达20%，展现了较大的变形能力。通过有限元模拟和实验验证相结合的方法，研究了CIT 柔顺机构的扭转行为和力学性能。在LPBF成型CIT柔顺机构的应变达到15%之前实现了轴向压缩应变与旋转角度之间的近似线性关系。

Abstract

A novel compression-induced twisting (CIT)-compliant mechanism was designed based on the freedom and constraint topology (FACT) method and manufactured by means of laser powder bed fusion (LPBF). The effects of LPBF printing parameters on the formability and compressive properties of the laserprinted CIT-compliant mechanism were studied. Within the range of optimized laser powers from 375 to 450 W and with the densification level of the samples maintained at above 98%, changes in the obtained relative densities of the LPBF-fabricated CIT-compliant mechanism with the applied laser powers were not apparent. Increased laser power led to the elimination of residual metallurgical pores within the inclined struts of the CIT mechanism. The highest dimensional accuracy of 0.2% and the lowest surface roughness of 20 μm were achieved at a laser power of 450 W. The deformation behavior of the CIT-compliant mechanism fabricated by means of LPBF exhibited four typical stages: an elastic stage, a heterogeneous plastic deformation stage, a strength-destroying stage, and a deformation-destroying stage (or instable deformation stage). The accumulated compressive strain of the optimally printed CIT mechanism using a laser power of 450 W went up to 20% before fracturing, demonstrating a large deformation capacity. The twisting behavior and mechanical properties were investigated via a combination of finite-element simulation and experimental verification. An approximately linear relationship between the axial compressive strain and rotation angle was achieved before the strain reached 15% for the LPBF-processed CIT-compliant mechanism.