Multi-filament-wound Composite Parts And Equipment Development

Multidirectional filament wound products (MFWP) are structures wound with helical winding, hoop winding and zero degree winding (the winding angle is 0° ), bearing the special characteristics of zero degree winding which can greatly improve the tensile and bending properties of composite pipes. Many foreign researchers have paid great attention to such structures, but there are not many related literatures found in our country.Firstly, this paper studied the geometrical structure of MFWP. Based on the hypothesis that the yarns possess the cross-section shape of race-track, a calculating model was proposed for the fiber volume fraction of a unit cell of multidirectional filament wound products. The model showed that the factors influencing the fiber volume fraction include tow bandwidth, tow thickness, total number of winding cycles, winding angle and the inner radius of the product, but have nothing to do with the length of the cylinder. Then the fiber orientation formulas were deprived from the above model, and the processing parameters influencing the hoop orientation and axial orientation were analyzed. Furthermore, the values of the process parameters were calculated under the condition of the fiber volume fraction of hoop orientation was equal to that of axial orientation. And the results from the calculation model and the experiment were compared, which gives a good agreement between. In addition, the factors lowering the actual fiber volume fraction were analyzed.Secondly, this paper introduced the multidirectional filament winding equipment, in terms of its whole structure and the design of mandrel parts, transmission system and control system, focusing on the design and calculation of the line type law of the filament winding. The unique property of this equipment is the realization of pure zero degree winding using the specially-designed filament-reciprocation device. On this equipment more than ten MFWP have been fabricated, which showed that it can meet the need of MFWP very well.Thirdly, this paper studied the mechanical properties of the MFWP both in theory and experiment. Based on the Classical Laminated Plate Theory, the mechanical analysis model of the tubes was established and implemented by the program of Matlab language, from which the axial tensile strength and the axial compressive strength were predicted. Then the specimens with different parameters were fabricated and tested under axial tensile, axial compressive and radius compressive loadrespectively. The theoretical model met the experimental results well. Furthermore, the test results, the stress-strain curve and the failure form were analyzed, which showed that the axial properties of the MFWP were obviously strengthened with the incorporation of the axial reinforcement.Finally, the characteristics and application prospects of the MFWP were illustrated, and it was concluded that this structure can meet the need for high internal pressure and axial loads with reliable performance in industry.