Research And Development Of Continuous Variable Thickness Three-dimensional Woven Fabric

With the development of the aviation industry, the industry of aviation engine fuel efficiencyand emissions requirements continue to increase, aircraft engine design uses a bypass ratio isincreasing, along with increasing the size of the fan assembly, which makes the quality of the fansegment accounted for total engine weight ratio is also increasing. Reduce the quality of the fanblades is an important way to reduce the total weight of the engine. The composite material usedon the fan blades is an important method to alleviate the quality of the fan. With the furtherdevelopment of composite fan blades, foreign released3-D RTM molding large flow swept shapedcomposite wide-chord fan blades, using the technology to produce three-dimensional braidedcomposite fan blade perform, reducing the weight of the fan blades.Throughout the foreign high-performance aerospace engine composite fan blades status anddevelopment, resin-based composite materials to achieve the key technology to improve theefficiency of the engine, composite fan blades will certainly have greater prospects. And ourcountry as a study in the use of three-dimensional fabric composite fan blades are not a lot ofexpanded perform. Therefore, the research engine composite fan blades three-dimensional fabricperform has a certain significance. In this paper, the basic shape of the fan blades, which expandas a flat plate with variable thickness, and close the three-dimensional fabric properties, determinecomposite perform as a continuous variable thickness dimensional woven fabrics. Used the loomwith multi-eye and multi-rapier weave.First, this paper briefly introduces the loom with multi-eye and multi-rapier, and transform itlet-off mechanism, designed an automatic reversal let-off mechanism. During loom weaving, warptension for some reason reduced to zero or even relaxation, automatic reversal warp beam to keepthe warp tension evenly and retains the general let-off mechanism functions. After processimprovement, test weaving machine, weaving a continuous variable thickness3-D woven fabrics,uniform layers of warp tension, clear the shed for weft insertion successfully provided favorableconditions. Then, this paper combines the basic structure of the three-dimensional woven fabricsrespectively continuous variable thickness dimensional woven fabric made structure design.Combined thickness of the factors known continuous variable thickness organizational designprinciples:(1) When the warp yarn density constant, by gradually increasing the number of layers ofweft and warp yarns interwoven, intertwined in increasing the number of layers while increasingthe number of weft yarns;(2) Increase weft inlaid, weft increase in the number of fabric to increase the thickness of thefabric;(3) Combining the above two methods, change weft yarn linear density to achieve increasedthickness of the fabric.Comparison of three organizational design, multi-layer stitched organizational structuredesigned with larger changes, and in accordance with the requirements of the fan blade tipthinner.So, this paper determine use multi-layer stitched structure design continuous variablethickness three-dimensional woven fabric.Finally, this paper weaved multi-layer stitched organizational structure, designed threedifferent specifications samples. And measure Three-dimensional woven fabrics thickness dataand slice analysis. Analysis shows that: Change in the structure of the fabric caused thicknessvariations large, the same structure gradually increase interwoven layers caused modest thicknessincreasing is a lesser extent, thickness variation can be considered is continuous. Changed weftyarn linear density,the value of the adjacent section thickness less than1mm, can be considered toachieve a continuous variable thickness three-dimensional woven fabric. And the fabrics off loom,which have structural stability, uniform appearance, the fabric thickness of almost continuouschange and the large increase in the overall thickness of the fabric, certification the scheme ofthis paper is feasible.