Modeling of Steel Reinforced Flexible Hoses

Abstract

Steel reinforcements are commonly used to strengthen rubber hoses which are used in high pressure applications (in the field of engineering). Reinforced hoses become stiff when subjected to pressure. Thus, there is a requirement to model reinforcements which would predict the effect of stiffening. Modeling helically wounded reinforcements is the main focus of this work. Deformation of helically reinforced rubber hoses under pressure depend on the helix angle at which the reinforcement is laid around the hose. The current study was carried out at Fraunhofer Chalmers Centre and used its in-house solver to perform numerical calculations. Additional functionalities have been added to the solver to model reinforcements. The reinforcements are generally modeled using one-dimensional elements which are incorporated inside a volume model of rubber. In this work, truss elements are formulated to model reinforcements. Primarily, two models have been implemented, namely, the coupled model which models rubber and reinforcements separately with a spring constraint on the their displacements to couple them together and an embedded model which involves adding the stiffness contribution of the 1D model to the 3D model. Other simplified models have also been considered. The effect of the neutral angle, at which the reinforced hose does not deform axially under an internal pressure, has been captured by all the models with the coupled and embedded models having a good agreement with the theoretical value. Further, bending and torsion experiments are simulated using the coupled model. The results of these simulations shows that the model is able to demonstrate the stiffening effect of reinforced hoses and that there is a dependency between pressure and the stiffness of the hose.