Anisotropic Large Deformation and Fatigue Damage of Rubber-fabric Braid Layered Composite Hose

Abstract

Rubber hoses are widely used in various transport and industrial systems to safely deliver high-pressure working oil without leakage. Usually, those are in a lamination composition of rubber and braided layers to suppress the extreme radial expansion stemming from high internal oil pressure. Braided layers manufactured by fabric or metallic cords are in a complex periodic pattern composed of warp and fill tows, so that those exhibit the inherent anisotropic behavior even though their base cords are isotropic materials. The anisotropy of braided layers causes the out-of-plane deformation of the entire rubber-braid layered composite hose, which becomes more prominent when the composite hose is under the large cyclic motion. A representative example is a braking hose used in automotive hydraulic braking system, in which the hose exhibits the large cyclic dynamic deformation according to the steering and bump/rebound motions of vehicle. The anisotropic large deformation characterized by the out-of-plane deformation in cyclic motion affects not only the hose deformed layout but also the hose durability. Hence, beside the oil-leakage prevention, the deformed layout and durability should be also considered in the design of braided composite hose. Meanwhile, owing to the complex micro structure of braided layers, these two subjects have been traditionally assessed by time-and cost-consuming trial-and-error experiments. In this context, this paper proposes the numerical method for predicting the deformed layout and the fatigue damage by utilizing the large deformation nonlinear finite element analysis. The troublesome braided layers in micro structure are modeled as orthotropic solid by making use of the homogenization method, and the deformed layout was analyzed by the updated Lagrangian method. Meanwhile, the fatigue damage was evaluated by making use of the modified Morrow fatigue model and Minor rule. Using the proposed numerical method, the characteristics of deformed layout and fatigue damage were investigated. (C) 2017 The Authors. Published by Elsevier Ltd.