Research On Enhancement Technology In Z-direction Of 3D Weaving Composites

Composites are used more and more widely in the industries of aerospace,automobile,and national defense due to its lightweight and high-strength features.However,a technological dilemma is found:composites' performance in Z direction is poor.China Academy of Machinery Science&Technology(CAM)invents a method of 3D weaving forming for composites,and this forming technology can improve the composites' performance in Z-direction.And this paper studies the factors and mechanism of enhancement technology in Z-direction of 3D weaving composites,by testing the performance of 3D weaving composites impact resistance in Z-direction,the compression performance in Z-direction,and the inner surface impact resistance of 3D weaving composites.By testing the performance of impact resistance in Z-direction of 3D weaving composites specimens of different factors,the regularity and extent of influence of both the structure and layout of the guide sleeves,the fiber volume content,and fiber weaving path and scan angle on the performance of impact resistance of 3D weaving composites were studied.By analyzing the microstructure and fracture morphology of specimens,the mechanism of the guide sleeves,weaving fibers and fibers in the guide sleeves to improve the impact load in Z-direction of 3D weaving composites was showed.Meanwhile,by observing the morphology of the specimens after compression failure,destruction process and failure mechanism of compression load in Z-direction were analyzed.By testing the compression performance in Z-direction of 3D weaving composites specimens of different factors,the regularity and extent of influence of both the structure and layout of the guide sleeves,the fiber volume content,and fiber weaving path and scan angle on the compression performance of 3D weaving composites were studied.After that,by establishing 3D weaving composites unit cell model,the correspondence between the guide sleeves' diameter and center distance and the guide sleeves' volume content and the side area was got.The regularity of influence of the guide sleeves' center distance on the inner surface impact resistance of 3D weaving composites was studied,when the guide sleeves' diameter was constant.Based on this,the regularity of influence of changing both the guide sleeves' diameter and the center distance on the inner surface impact resistance of 3D weaving composites was studied,when the guide sleeves' volume content was constant.