Abstract

3D braided composite is gaining popularity over the traditional composite because it has a higher impact resistance, fatigue strength, stiffness in the thickness direction, anti-delamination capability, etc. Based on bridging models, the fibers are considered as transversely isotropic and matrix isotropic. The equivalent material properties of the composites are computed using a volume averaging method (VAM). The four steps 1 × 1 braided technique are introduced to manufacture the 3D braided singly and doubly curved shell panels. The bridging model claimed to be more accurate in predicting mechanical properties and shear modulus in comparison with the other method. In the present study, the free vibration response of 3D braided curved panels is obtained using finite element methods (FEM). A third-order shear deformation (TSDT) with twelve degrees of freedom per node is for the first time employed in 3D braided panels using eight nodded isoparametric formulation. In this theory, the transverse displacement is the function of the thickness coordinate. In reality, the normal stress of the thick shells in the thickness direction can't be neglected. This theory having the capability of predicts the normal stress in the thickness direction. Hence, to predict the accurate results of the 3D braided shell, it has more capability compared to the other shell theory. The free vibration results of the shell panels' viz. cylindrical shells (CYS), elliptical paraboloid shells (EPS), and hyperbolic paraboloid shells (HPS) are computed at a different braided angle, braided volume fraction, aspect ratio, thickness ratio, curvature ratio, and boundary conditions, etc.

• HIGHLIGHTS

• The equivalent material properties of the 3D braided composites are calculated using bridging models based on a volume averaging method (VAM).

• The bridging model claimed to be more accurate in predicting mechanical properties and shear modulus in comparison with the other method.

• A third-order shear deformation (TSDT) with twelve degrees of freedom per node is for the first time employed in 3D braided panels using eight nodded isoparametric formulation.

• In this theory, the transverse displacement is the function of the thickness coordinate. To predict the 3D braided shell's accurate results, it has more capability than the other shell theory.

• The free vibration results of the shell panels' viz. cylindrical shells (CYS), elliptical paraboloid shells (EPS), and hyperbolic paraboloid shells (HPS) are computed at a different braided angle, braided volume fraction, aspect ratio, thickness ratio, curvature ratio, and boundary conditions, etc.

摘要

3D编织复合材料比传统复合材料越来越受欢迎，因为它具有更高的抗冲击性、疲劳强度、厚度方向的刚度、抗分层能力等。基于桥接模型，纤维被认为是横向各向同性和基体各向同性的。使用体积平均法 (VAM) 计算复合材料的等效材料特性。引入了四步 1×1 编织技术来制造 3D 编织单曲和双曲壳面板。与其他方法相比，桥接模型声称在预测机械性能和剪切模量方面更准确。在本研究中，使用有限元方法 (FEM) 获得 3D 编织曲面面板的自由振动响应。每个节点具有十二个自由度的三阶剪切变形 (TSDT) 首次用于使用八点等参公式的 3D 编织面板。在这个理论中，横向位移是厚度坐标的函数。现实中，厚壳在厚度方向的法向应力是不可忽略的。该理论具有预测厚度方向正应力的能力。因此，在预测 3D 编织壳的准确结果方面，它比其他壳理论具有更多的能力。壳板的自由振动结果即。圆柱壳 (CYS)、椭圆抛物面壳 (EPS) 和双曲抛物面壳 (HPS) 以不同的编织角、编织体积分数、纵横比、厚度比、曲率比、

• 强调

• 使用基于体积平均法 (VAM) 的桥接模型计算 3D 编织复合材料的等效材料特性。

• 与其他方法相比，桥接模型声称在预测机械性能和剪切模量方面更准确。

• 每个节点具有十二个自由度的三阶剪切变形 (TSDT) 首次用于使用八点等参公式的 3D 编织面板。

• 在这个理论中，横向位移是厚度坐标的函数。在预测3D编织壳的准确结果方面，它比其他壳理论更有能力。

• 壳板的自由振动结果即。圆柱壳（CYS）、椭圆抛物面壳（EPS）和双曲抛物面壳（HPS）在不同的编织角度、编织体积分数、纵横比、厚度比、曲率比和边界条件等下计算。