薄层合板单面贴补修理拉伸性能研究

STUDY ON THE TENSILE PROPERTY OF SINGLE SIDE PATCH REPAIR OF COMPOSITE LAMINATES

贴补修理是工艺简单、应用较广的复合材料结构修补技术。对含有孔穿透损伤的复合材料层合板单面贴补修理试验件进行拉伸试验,保持补片的铺层顺序、厚度不变,改变补片的直径,考察补片直径对单面贴补修理效果的影响,并根据试验过程中采集的试验件相应位置的应变数据以及载荷位移曲线分析其失效机理。结果表明,单面贴补修理试验件的强度恢复率约为34%～50%,且贴补修理对于含穿透孔损伤层合板的刚度具有一定的恢复作用,而且随着补片直径的增大,强度恢复率增高。当补片直径较小时,胶层先于母板发生破坏,此时的修理效果不明显;当补片直径增大到一定程度后,胶层承载能力较高,此时贴补修理对损伤件的拉伸强度有一定的提高作用。在试验基础上建立了有限元模型,能有效预测贴补修理件的破坏模式、拉伸强度,并可分析得到试验件的应力分布;改变有限元模型参数,研究最佳效果的补片尺寸与损伤孔径之间的关系。结果表明,当补片直径比损伤孔径大30 mm～40 mm时可获得较高的修理效率。为复合材料层合板设计贴补修理方案提供了参考。

Patch repairis a technologically simple and extensively employed composite structure repair technology. Tensile experiments on the composite laminate for experimental purpose with through-hole damage after single side patch repair is conducted. During the experiments,a research on how the diameter of patch influence the effectiveness of single side patch repair by changing patches' diameters while keeping their ply stacking sequence and thickness constant is accomplished as well as an analysis of its failure mechanism based on the strain data of laminates at corresponding places collected during the experiment and the load-displacement curve on the basis of the data. The results show that the recovery rate of failure strength of test pieces after single-side patch repair is about 34% to 50%,and bonded repair has a recovery effect on the stiffness of laminates with through-hole damage. The longer the patch diameter,the higher the recovery rate of failure strength. When the patch diameter is relatively short,the adhesive fails before parent laminate. Hence,the repair effect is not obvious under this circumstance. When it increases to a certain extent,the strength of the adhesive is higher than parent laminate. At this time,patch repair can help increase the tensile strength of the damaged specimen. A finite element model is established based on the experiments,which can effectively predict failure modes and tensile strength of the test pieceand analyze its stress distribution. By changing the parameters of the model,a study on the relationship between patch sizes and damage apertures providing best repair effect is conducted. The results show that high repair efficiency can be obtained when the patch diameter is 30 mm^40 mm longer than the damage aperture. This paper provides references for composite laminates patch repair plan design.