Research Of Mechanical Performance Of Knitting Cord Reinforced Rubber Hose

Knitting cord reinforced rubber hose can be used to transport liquid,gas and solid.It has high compression strength and high modulus.It is widely used in automobile,aerospace and other fields.The materials of rubber and enhancement layer and the structure of rubber hose have impact on the hose's mechanical properties.It has important guidance significance to study the mechanical properties.This paper focused on the aramid cord reinforced EPDM rubber hose which diameter was 26 mm,wall thickness was 7.5mm,cord needle number was 18 needles and cord equivalent radius was 0.67 mm.Firstly,the stress-strain curve of rubber was tested to match double parameters Mooney-Rivilin model to perform the rubber's mechanical properties.The line elastic parameter of cord was tested by the uniaxial tension of aramid.The rubber hose's bursting pressure was also tested through experiment.Then the 3D model of knitting cord reinforced rubber hose was established by the Pro/E software.The mechanical properties were simulated by the ANSYS-Workbench.The best model and constraint were discussed and the effect of cord's needle number and hose's thickness were also studied.Then the effect of solvent and arrangement density of cord on the peel strength were researched by the experiment.Finally the following conclusions were got:(1)The simulation results showed that the best modeling scheme of knitting cord reinforced rubber hose was lapped type.The best constraint scheme was displacement controlled type.When the rubber hose was under 0.24 MPa pressure,cord's maximum equivalent stress was 67.21 MPa and the rubber's maximum equivalent stress was0.20 MPa.When the rubber hose was under 2.10 MPa pressure,the cord's maximum equivalent stress reached the cord's tensile strength 589 MPa,the rubber's maximum equivalent stress was 1.77 MPa which was smaller than the rubber's tensile strength11.9MPa.The cord was broken before the rubber and this phenomenon was in accordance with rubber hose's actual bursting process.The rubber hose's actual bursting pressure was 2.04 MPa and the simulation result was 1.03 times of the experimental result.The error was 2.94%.(2)The simulation results showed that,when the cord needle number increased from 5 to 10,the cord's maximum equivalent stress decreased sharply.When the needle number exceeded 10,the cord's maximum equivalent stress was stable.When the cord needle number increased from 5 to 15,the rubber's maximum equivalent stress decreased sharply.When the needle number exceeded 15,the rubber's maximum equivalent stress was stable.When the cord needle number increased from5 to 10,the maximum deformation of cord and rubber decreased sharply.When the needle number exceeded 10,the the maximum deformation of cord and rubber were stable.(3)The simulation results showed that,when the rubber thickness increased from2.75 mm to 4.75 mm,the maximum equivalent stress and the maximum deformation of cord increased gently.The maximum equivalent stress of rubber was stable and the maximum deformation of rubber decreased at first and then increased.(4)The experimental results showed that when the toluene's ratio increased,the peel strength between inner and outer layer increased at first and then decreased.When the proportion of toluene and gasoline was 7:3,the T type peel strength between inner and outer layer was the largest of all.The maximum peel strength was175.43 N and the average peel strength was 169.11 N.(5)The experimental results showed that when the cord's arrangement density increased,the peel strength between inner and outer layer increased at first and then decreased.When the cord's arrangement density was 16 roots/3cm,the peel strength was the largest of all.And the maximum peel strength was 258.07 N and average peel strength was 240.21 N.When the cord arranged very close,the peel strength between inner and outer layer was even much smaller than that with no cord.