航空学报 > 2022, Vol. 43 Issue (6): 526117-526117   doi: 10.7527/S1000-6893.2022.26117

固化残余应力对无人机复合材料机翼强度的影响

刘振东, 郑锡涛, 范雯静, 张东健   

  1. 西北工业大学 航空学院, 西安 710072
  • 收稿日期:2021-07-16 修回日期:2022-06-22 出版日期:2022-06-15 发布日期:2022-02-28
  • 通讯作者: 郑锡涛,E-mail:zhengxt@nwpu.edu.cn E-mail:zhengxt@nwpu.edu.cn
  • 基金资助:
    陕西省自然科学基础研究计划(2020JQ-113)

Effect of process-induced residual stress on strength of UAV composite wing

LIU Zhendong, ZHENG Xitao, FAN Wenjing, ZHANG Dongjian   

  1. School of Aeronautics, Northwestern Polytechnical University, Xi'an 710072, China
  • Received:2021-07-16 Revised:2022-06-22 Online:2022-06-15 Published:2022-02-28
  • Supported by:
    Natural Science Basic Research Program of Shaanxi (2020 JQ-113)

摘要: 复合材料的力学性能与复合材料的固化过程密不可分。复合材料在固化过程中,由于树脂固化收缩、纤维与基体之间的热膨胀系数不匹配等因素,会产生固化残余应力与固化变形。该固化残余应力会影响复合材料结构的力学性能,甚至会引起分层、基体开裂等严重缺陷。因此,有必要研究固化残余应力对复合材料结构强度的影响。针对某型复合材料机翼,首先利用ABAQUS有限元分析软件进行二次开发,建立了一套基于各向异性黏弹性本构模型的复合材料固化过程分析方法,计算所得固化变形量与试验值误差小于8.24%。其次,采用Hashin强度准则,建立了全复合材料无人机机翼的强度分析有限元模型,机翼失效载荷的预测值相对试验值误差为9.85%。随后,将复合材料固化过程中产生的残余应力作为初始应力条件添加到强度分析模型中,通过有限元方法研究残余应力对全复合材料无人机机翼强度的影响。为研究不同固化参数产生的固化残余应力对结构强度的影响,在合理范围内提出了另外2种固化工艺曲线。模拟结果表明:对于该全复合材料无人机机翼结构而言,固化残余应力导致强度下降,使其强度降低了3.52%,且较优的固化工艺参数下的结构强度比原始固化工艺参数下的结构强度高1.3%。

关键词: 固化残余应力, 固化变形, 固化工艺参数, 复合材料机翼, 结构强度

Abstract: The fabrication process has considerable effect on the performance of fully-cured composite structures. During the curing process, the process-induced residual stress and deformation are generated due to the chemical shrinkage and mismatch of thermal expansion coefficient, et al. The residual stress can potentially lower the performance of composite structures, or even leads to such defects like delamination. Therefore, it is necessary to study the influence of residual stress on the strength of composite structures. Firstly, based on anisotropic viscoelastic constitutive model, a numerical model predicting the residual stress and cure deformation of composite specimen was established. The 3D viscoelastic model was employed in this model and its corresponding finite element code was incurporated into ABAQUS, the relative error of cure deformation between numerical results and experimental data was less than 8.24%. Secondly, a strength predicting numerical model based on the Hashin damage criteria was built. The numerical results have been proved to fit the experimental data in good agreement, the relative error in strength is 9.85%. Then, the residual stress was conducted into the strength predicting model as an initial condition. Thus, the effect of residual stress on the strength of Unmanned Aerial Vehicle (UAV) composite wing structures was numerically studied. To study the effect of different residual stress level on the strength behavior of UAV composite wing structure, 2 different curing parameters were generated. The numerical results show that the residual stress is harmful for the strength behavior of this UAV composite wing structure. The numerical ultimate strength of wing structure was reduced by 3.52% due to the curing residual stress. However, the strength of the wing structure with optimized curing parameter is 1.3% higher than that of the original one.

Key words: process-induced residual stress, process-induced deformation, curing parameter, composite wing, structural strength

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