| The composites sandwich structures have been studied for over 50 years. It has been widely used in aerospace, marine and civil departments due to its lightweight and high stiffness. Multi-axial warp knitted fabrics are a kind of non-crimp reinforcements. Yarns in the reinforcements are straight to bear load. The strength of the yarns can be got fully used in composites, which gives good mechanical property, fatigue resistance and damage tolerance.With the investigation on multi-axial warp knitted fabrics and the composite molding technology, the multi-axial reinforced composite sandwich is getting applied in yacht, wind blade etc.This paper discussed the composite sandwich molding process. It included the selection of reinforcements, core materials and resin system. The molding process was optimized. The component ratio of resin and technical parameters were settled down.During the composite sandwich molding process, much more attention was paid on various methods to prepare PVC core materials. The factors, which significantly influence the flow front of the resin, were discussed. The reasonable method for preparing core materials was obtained. A new composite core molding process was introduced with an inlaid distribution media.The bending and compression properties of the composite sandwich panels were tested. The influence of the fabric area weight, lay-up angle, thickness of core material, the mat and molding processes have been discussed. With the help of AE test, the damage behavior of the sandwich structures was analyzed.Finally, a composite sandwich for nacelle cover of the wind turbine, 7mx2m, was successfully made by vacuum assistant resin transfer molding process.The influences of the reinforcements and core materials on the composite sandwich structures were discussed in the paper. The problems met during experiments were solved. The real practice was made in the work. It will be very helpful to guide the production of composite sandwich structures.
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