Based On Multi-scale Method The Failure Study For Woven Composite Pressure Pipe

Because of a number of advantages,such as high strength,light weight,safety of failure,good corrosion resistance,composite pressure pipe have been widely used in the oil industry,construction drainage,chemical corrosion protection,etc.At present,the filament winding process is mainly used for composite pressure piping manufacture.Although the mechanical properties and bearing capacity of filament winding pressure pipe can be improved by the composite pressure pipes,the filament wound pressure pipe is a laminate structure.When the laminate is subjected to load,the interlayer is only bonded by the matrix,which leads to the weak interlayer and shear strength,which will lead to the failure of the matrix cracking,fiber/matrix interface debonding and delamination.In order to overcome the mechanical defects,the 3D orthogonal woven technology is applied to the structure design of the composite material pressure pipe,and the woven composite pressure pipe is designed in this paper.Compared with the filament winding pressure pipe,the composite material layer of woven composite pressure pipe has a great difference in the macroscopic and microscopic aspects.The main contents of the full text are divided into the following points:(1)Based on the three-dimensional orthogonal woven technology,the yarn direction and bending degree of the composite layer of the woven composite pressure pipe are analyzed in this paper.Based on the microstructure of the woven preform,the overall geometric model of the woven composite pressure pipe and the geometric model of the representative volume unit are established.The macroscopic properties of woven composite materials are simulated by the micromechanical and elastic properties of composite materials,which the correctness of the theoretical analysis of elastic properties is proved and the theoretical basis is provided for multi-scale analysis of composite material layer of woven composite pressure pipe.(2)Based on the periodic structure of the composite layer of the woven composite pressure pipe,the effective elastic modulus of the composite layer of the macro woven composite pressure pipe is predicted by the multi-scale analysis and the geometric model of the meso representative volume element,the corresponding component characteristics and the woven geometric parameters.And under the same yarn volume fraction,the mechanical properties of woven composite pressure pipe are predicted,and compared with filament winding pressure pipe.(3)Through composite material progressive damage theory,the gradual damage process of the composite layer of the composite pressure pipe is studied systematically under internal pressure.Under specific volume fraction,the effective mechanical properties of the composite layer of woven composite pressure pipe is analyzed and studied by the finite element method,and compare with the composite layer of filament wound pressure pipe.With the different volume fraction,the mechanical properties of woven and filament composite pressure pipe are studied.