Mechanical Properties Of Continuous Glass Fiber Reinforced Composite Pipe Ability To Analyze And Research

Continuous glass fiber reinforced composite pipe(RTP pipe for short)is a new type of composite pipe with excellent performance.Due to its advantages of light weight,impact resistance and corrosion resistance,it has attracted high attention in developed countries,and has become a new choice for offshore oil and gas transportation pipelines.However,in the process of deep sea service,RTP pipeline is often subjected to huge internal pressure loads,and the pipeline will be subjected to impact loads similar to the falling objects in fishing activities of fishing vessels and ships anchoring.At this time,once the pipeline breaks,the consequences will be disastrous.Therefore,it is very important for engineering application to analyze and study the mechanical properties of RTP tubes.This thesis mainly carries out the following research contents:First of all,in view of the complexity and particularity of RTP pipe,this thesis analyzes the production process of RTP pipe,makes basic assumptions about its material and structure,and designs the parameters of the pipe.The inner and outer layers of the pipeline are made of high-density polyethylene,and the middle reinforced layer is wound alternately on the lining pipe with ±55° by continuous glass fiber reinforced prepreg tape(CFRT-GE6550),and each layer is bonded together by heating fusion method.Based on the three-dimensional orthogonal anisotropic elasticity theory,the elastic parameters of CFRT-GE6550 were calculated by Halpin-Tsai combined model method,and the tensile strength was obtained from the ratio of glass fiber to HDPE in CFRT-GE6550,and the calculated results were verified by tensile test.Secondly,theoretical calculation and finite element simulation are used to analyze the ultimate internal pressure load of RTP tube.According to the mechanical properties of composite materials,a simplified model is established for RTP pipe,and the maximum stress failure criterion is used to analyze and calculate the bursting value of internal pressure of the composite pipe.Finite element analysis software ABAQUS was used to establish the finite element model under internal pressure load,and the stress analysis of each layer under the same internal pressure was carried out.It is found that the CFRT-GE6550 in the reinforcement layer plays a major role in the internal pressure load,and the pressure of the internal reinforcement layer is greater than that of the external reinforcement layer,that is,the internal reinforcement layer will fail first.Then,the bursting pressure engineering formula and short time bursting pressure test of RTP pipe are studied,and different pipe parameters are analyzed.During the test,the load time history curve of RTP pipe from the beginning of pressure to pipe rupture was recorded in real time to determine its final burst pressure.Compared with the finite element,engineering formula and theoretical calculation results,the reliability of these methods is fully proved.In addition,the sensitivity analysis of three parameters,namely the number of winding layers,winding Angle and diameter thickness ratio of RTP reinforced layer,was carried out to further understand the influence of different parameters on the mechanical properties of RTP tube.Finally,ABAQUS/Explicit dynamic analysis solver is used to study the impact resistance of submarine pipeline under the action of falling objects.A three-dimensional nonlinear dynamic finite element model of falling object-seabed soil-pipeline was established,and the damage and deformation of bare RTP pipeline and buried RTP pipeline under the impact of falling object were compared.Then the mechanical response characteristics of submarine RTP pipeline under the impact load of falling objects are studied from the mass size,falling velocity and buried depth of the pipeline.