| Thermoplastic composite is the general term of composite based on thermoplastic resin and reinforced by all kinds of reinforcing fibers, such as glass fiber, carbon fiber. Thermoplastic composites have a number of important advantages over thermosetting composites for instance, better toughness/damage tolerance, longer service life, recyclable, and shorter processing period. The most important and potential advantage of thermoplastic composite is the automatization of processing, which can reduce the costs of the final products. Therefore, it is predictable that thermoplastic composites will come into use in a rapid and wide way in the future. Especially thermoplastic composites with commingled fiber have been developed rapidly and used widely in recently years. Though people have realized the advantages and potentials of thermoplastic composites in structure manufacture, the development and study of practical processing technique has been conducted only in recent ten years. At present, the successful application processes mainly are pultrusion process, winding and uni-direction band compressing molding process, etc.Three-dimensional fabric used as preform of weaving structural composite is ideal material with excellent integrity; its toughness, damage tolerance and reliability are better than traditional materials. The research of there-dimensional preform has a history over twenty years, though great progress has been made, high performance fibers such as glass fiber and carbon fiber are easy to be damaged because of the complex motion and the great friction between fibers during fabric production, which limits the weaving efficiency greatly.In this paper, a kind of low-cost but effective manufacturing technology of 3D woven thermoplastic composites is designed, and micro-braided yarn is chosen asthe medium to meet the requirement of rapid, even impregnating and rigorous 3D weaving condition, which inaugurates a new approach for weaving 3D weave and producing thermoplastic composites. Along with the fiber-resinimpregnating model's construction, the transverse finite impregnating model and lognitudinal-impregnating model of fibers are also constructed. Theimpregnating and flowing patterns of resin-air among the fibers are established according to the theory of two-phase fluid dynamism. These models can explain the results of the experiment done before and are proved to be correct by the experiment of this research. The relationships among the processing-microstructure-property of the 3D woven thermoplastic composites are established, which offer theoretical foundation for determining the reasonable processing technique and improving the composites' quality.The core yarn is wrapped tightly and firmly by micro-braided yarn's wrapping fibers with little hair on its surface and has good weaving properties under the circumstances of non-sizing. The less the diameter of reinforcing fiber (core yarn), the better quality of the final material. However, when the core's diameter is too small, the spinning efficiency is low. The geometry model of 3D woven structure indicates that the factors that influence the binder orientation angle mainly include the aspect ratio of weft yarn cross section, binding pattern, the shot diameter of binder and weft density. A good agreement is demonstrated between theoretical predictions and experimental results.Temperature, pressure and time are the most important parameters in the fabrication process. Rising temperature may reduce resin viscosity. Temperature has great influence on viscosity of the resin when melting point of PP resin is within 160 ~200 C; but viscosity varies slightly over 200 C. Experiment demonstrates when temperature is over 180掳C, resin overflows easily, and the surface resin's color becomes faint. The processing pressure which influences the combination state, the flowing behavior of the matrix among the fiber bundles, the overflowingcharacter should be determined by the woven structure, the temperature...
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