Research For The Bonding Mechanical Properties Of Epoxy Resin Adhesives In Flexible Pipeline End Fitting

With the development of adhesives,bonding systems have been widely used in aerospace,automotive,and other fields.But the stringent requirements for the use of adhesives in marine water environments,Adhesive application and research in the field of the development of marine resources and equipment are very few.Epoxy adhesives have good toughness properties due to their good bonding properties.So They are most commonly used.Effective application of such adhesives is critical for the design of new adhesive bonding structures to achieve product updates.In the development of marine resources,flexible pipelines play an important role.End Fittings are critical equipment for connection between pipelines and ships,platforms,etc.Their connection performance determines the carrying capacity of pipelines.The connecting part of the End Fitting is the adhesive lock of the epoxy resin adhesive and the pipeline tensile armour layer.Due to the limitations of the End Fitting processing technology and the adhesive performance,the strength of End Fittings independently designed and developed by us is not enough,which seriously affects the End Fittings.The laying depth of the pipeline.This article focuses on epoxy resin bonding technology and End Fitting bonding strength issues,research content in the following aspects.1)This article first introduced the application of bonding technology,epoxy resin adhesives,non-bonded flexible pipe structure and its End Fitting bonding mechanism and analyzed the connection failure mechanism of adhesive End Fittings.2)Then,for the application of flexible pipe End Fittings to high-strength tensile conditions,the bonding connection between metal armored steel wire and epoxy resin adhesives is considered with emphasis,and the problem of End Fitting bonding is studied.Including the preparation of high shear strength epoxy adhesives,adhesive material performance testing,bonding model numerical simulation calculation,straight steel wire drawing,bending steel wire tensile test and numerical simulation verification.3)This article focuses on the effect of the shear properties of the adhesive on End Fitting strength,the use of carboxyl-terminated nitrile rubber tougheners and SiO₂,Al₂O₃ and other different nano-fillers to modify the epoxy adhesive,and its properties.The test and analysis showed that the addition of the same composition of SiO₂ had the greatest increase in the tensile strength of the adhesive,while addition of Al₂O₃ increased the shear strength of the adhesive.At the same time,the thickness of the adhesive layer was analyzed.It was found that when the thickness of the adhesive layer was less than 1mm,the connection strength was the greatest and the change was not significant.An epoxy adhesive suitable for the high strength of marine pipe End Fittings was obtained.4)Analysis of the numerical model and experimental analysis of the straight wire tensile model with thick bonding layer.The adhesive strength does not change with the thickness of the colloid when the bonding thickness is greater than 5mm.Analysis of bending wire bonding stretch In the model,the colloidal thickness has a great influence on the failure mode of the bended steel wire tensile specimens,and two adhesive layer fractures can be performed during the stretching.When the colloid thickness is 7.5 mm,the End Fitting connection performance can be obviously improved,and the End Fittings are performed.Secondary connection protection;5)Finally,the modified adhesive is applied to the connection of flexible pipe End Fittings,and the entire pipeline is experimentally verified.Analysis of experimental data proves that the End Fitting bonding strength meets the conditions and meets the service standards.