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针对含孔边分层复合材料沉头螺栓连接结构,通过挤压试验及有限元仿真,研究了孔边分层对复合材料连接结构力学性能的影响。通过连接孔的挤压试验,得到了不同类型试验件的承载能力与破坏模式。有限元仿真中,基于ABAQUS有限元分析软件建立了复合材料机械连接的三维有限元模型,进行复合材料渐进失效损伤模拟,并采用内聚力单元来模拟预制分层。有限元计算得到载荷-位移曲线和变形模式与试验吻合较好,从而验证了有限元模型的有效性。在此基础上,分析了含孔边分层的复合材料机械连接结构的破坏机理,并研究了分层位置、分层面积大小和分层形状对该结构承载能力的影响。研究表明:复合材料的破坏始于沉头孔中的直孔区域且当预制分层位于直孔区域时,结构的承载能力最低;分层形状为圆形和正方形时,会严重影响结构的承载能力,分层形状为椭圆形时,对承载能力影响较低。无论分层形状如何变化,分层总是从受挤压的一侧开始,以半圆弧的形状向受挤压方向进行扩展。
Aiming at the subsidence composite pierce bolt connection structure with hole edge, the influence of hole edge stratification on the mechanical properties of the composite connection structure was studied by means of compression test and finite element simulation. Through the hole extrusion test, the bearing capacity and failure modes of different types of test pieces were obtained. In the finite element simulation, a three-dimensional finite element model of the mechanical connection of the composite material was established based on the ABAQUS finite element analysis software to simulate progressive failure damage of the composite material. The cohesion element was used to simulate the prefabricated delamination. The load-displacement curve and deformation mode obtained by the finite element method are in good agreement with the experimental results, which verify the validity of the finite element model. On this basis, the failure mechanism of the mechanical connection structure with hole edge layering is analyzed, and the influence of layering position, delamination area and delamination shape on the bearing capacity of the structure is also studied. The results show that the failure of composites starts from the straight hole in the counterbore and the bearing capacity of the structure is the lowest when the preform stratification is located in the straight hole. When the stratification is round or square, the bearing of the structure will be seriously affected Capacity, layered shape oval, the bearing capacity of the lower impact. Regardless of how the delamination shape changes, delamination always begins at the pinch side and expands in the direction of the pinch by a semicircular arc shape.