文章信息/Info

Title:

Mesostructure Analysis of 3D Flexible Woven Preform

文章編號:

1674-3962(2020)06-0458-06

作者:

劉云志; 戰麗; 王爭; 張群; 李志坤

（機械科學研究總院集團有限公司 先進成形技術與裝備國家重點實驗室，北京 100083）

Author(s):

LIU Yunzhi;  ZHAN Li;  WANG Zheng;  ZHANG Qun;  LI Zhikun

（Key Laboratory of Advanced Forming Technology and Equipment, China Academy of Mechanical Sciences Group Co., Ltd., Beijing 100083, China）

關鍵詞:

柔性導向三維織造; 復合材料預制體; 樹脂轉移模塑成型（RTM）技術; 細觀結構; 纖維截面形貌

Keywords:

3D flexible weaving technology;  composite preform;  resin transfer molding (RTM) technology;  mesostructure;  sectional morphology of fibers

分類號:

TB332

DOI:

10.7502/j.issn.1674-3962.201902007

文獻標志碼:

A

摘要:

針對柔性導向三維織造復合材料預制體的結構表征問題，對預制體的幾何結構和纖維束細觀形貌進行了研究。基于纖維截面為矩形、纖維處于伸直狀態、預制體結構均勻一致、忽略邊緣導向套與纖維的纏繞區域等基本假設，建立了預制體幾何結構模型，并通過織造實驗驗證了模型的合理性。通過織造層致密化壓實工藝，織造了纖維體積分數分別為44.1%、50.0%和52.5%的預制體，采用樹脂轉移模塑成型（RTM）技術制備了復合材料試樣。將試樣研磨拋光后置于顯微鏡下觀測X/Y向纖維束沿Z向和軸向的截面細觀形貌變化特征（將纖維與平面內X或Y向纖維之間正交鋪設的夾層區域定義為A區域，將X向纖維和Y向纖維正交疊層區域定義為B區域）。結果表明，受不同壓實載荷的影響，纖維體積分數高的預制體，A區域的X/Y向纖維束截面形貌更趨于矩形；B區域的X/Y向纖維束，在預制體纖維體積分數達到50%時，呈輕微的反半圓形狀，纖維體積分數達到52��5%時，纖維束截面近似呈矩形；X/Y向纖維束沿軸向截面觀測結果顯示，在A區域和B區域的纖維束軸向截面形貌分別形成反鼓形和鼓形結構，沿著纖維束軸向交替重復出現，且隨著壓實載荷的增加，制件纖維體積分數提高，該特征更加明顯。通過分析碳纖維預制體細觀結構特征，得出宏觀壓實致密化程度對預制體細觀結構的影響規律，為預測復合材料性能提供了參考。

Abstract:

Targeting at the problem of structure characterization of 3D flexible woven preform, the macroscopic geometry of preform and the mesostructure of fiber bundle were studied. Based on the basic assumptions that the fiber cross section is rectangular, the fiber is straight, the structure of preform is uniform, and the winding area between edge guide sleeve and fiber is ignored, the macroscopic geometric structure model of the preform was established, and the rationality of the model was verified by the weaving experiment. Through the densification and compaction process of the woven layer, the preforms with fiber volume fractions of 44.1%, 50.0%, and 52.5% were woven, and composite material samples were prepared using resin transfer molding (RTM) technology. After grinding and polishing, the mesomorphology of X/Y fiber bundles along Z direction and axial section was observed under microscope, as the sandwich area between Z direction fiber and X direction fiber or between Z direction fiber and Y direction fiber is defined as region A, and the orthogonal stacking region between X direction fiber and Y direction fiber is defined as region B. The results show that, under the influence of different compaction loads, the cross-sectional morphology of the X/Y direction fiber bundle in the A region for the preform with high fiber volume fraction tends to be more rectangular. The cross-sectional morphology of the X/Y direction fiber bundles in the B region shows a slight reverse semicircle shape when the fiber volume fraction of the preform reaches 50%, and it is approximately rectangular when the fiber volume fraction reaches 52.5%. The axial cross-section observation results of the X/Y fiber bundles show that the axial cross-sectional morphology of the fiber bundles in the A and B regions respectively form anti-drum and drum structures, which alternately and repeatedly appear along the fiber bundle axis. With the increase of compaction load, the fiber volume fraction of the part increases, and the above characteristics are more obvious. By analyzing the mesostructure characteristics of carbon fiber preform, the influence of compaction degree on the mesostructure of the preform was obtained, which provides a reference for predicting the performance of the composite materials.