Fiber reinforced rubber pipes are widely used to transport fluid at locations requiring flexible connections in pipeline systems. The spherical self-balancing fiber reinforced rubber pipes with low stiffness are drawing attention because of their vibration suppression performance under high internal pressure. In this paper, a theoretical model is proposed to calculate the axial stiffness and lateral stiffness of spherical self-balancing fiber reinforced rubber pipes. The inhomogeneous anisotropy of the reinforced layer and the nonlinear stress-strain relationship of the reinforced fiber are considered in the model. The accuracy of the model is verified by experimental results. Theoretical calculation finds that both the axial and lateral stiffness are influenced significantly by the key structural parameters of the pipe (the axial length, the circumferential radius at the end, the meridional radius, and the initial winding angle). The stiffness can be reduced remarkably with optimal meridional radius and initial winding angle, without any side effect on the self-balance of the pipe. The investigation methods and results presented in this paper will provide guidance for design of fiber reinforced rubber pipes in the future.

中文翻译：

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球形自平衡纤维增强橡胶管在内压下的轴向和横向刚度。

纤维增强橡胶管被广泛用于在管道系统中需要灵活连接的位置输送流体。低刚度的球形自平衡纤维增强橡胶管由于其在高内压下的减振性能而备受关注。本文提出了一种理论模型来计算球形自平衡纤维增强橡胶管的轴向刚度和横向刚度。在模型中考虑了增强层的不均匀各向异性和增强纤维的非线性应力-应变关系。实验结果验证了模型的准确性。理论计算发现，管道的关键结构参数（轴向长度，末端的圆周半径，子午线半径和初始绕线角）。通过最佳的子午半径和初始缠绕角度，可以显着降低刚度，而对管道的自平衡没有任何副作用。本文提出的研究方法和结果将为今后纤维增强橡胶管的设计提供指导。