一种改进的三维四向编织复合材料单胞模型及宏观弹性常数预测方法  

Improved unit cell model and elastic constant prediction method of 3D four-directional braided composites

作　　者：王荣桥[1,2,3] 刘茜 胡殿印 张龙 申秀丽[1,2,3] 

机构地区：[1]北京航空航天大学能源与动力工程学院,北京100191 [2]航空发动机结构强度北京市重点实验室,北京100191 [3]先进航空发动机协同创新中心,北京100191

出　　处：《复合材料学报》2017年第9期1973-1981,共9页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(51675024;51305012;51375031);航空科学基金(2014ZB51);国防基础科研计划(B2120132006)

摘　　要：提出了一种考虑打紧工艺导致纤维束截面形状沿其轨迹方向连续变化的三维四向编织复合材料改进单胞模型,并用于宏观弹性常数预测方法。首先,基于编织工艺过程分析,确定了单胞内部的纤维束布局形式;然后,从几何上推导了纤维束受挤压部位的位置坐标,并假设纤维束在受挤压前截面为圆形,受挤压部位发生圆形到椭圆的过渡变化,导致纤维轨迹产生弯曲,建立了纤维束截面为圆形和椭圆连续变化的改进单胞模型。通过该模型推导单胞编织参数和几何尺寸的数学关系,由此得出的几何特征数据与试件实测数据较为吻合,花节长度的预测值相对误差小于4%,相比于不考虑纤维束挤压变形的单胞模型更接近实际情况。最后,基于该改进的单胞模型,预测了三维四向编织复合材料的宏观弹性常数,并进一步研究了编织角和纤维体积分数对弹性常数的影响规律。An improved unit cell model for 3Dfour-directional braided composites was proposed,considering the cross-section shape variation of interior fiber bundles along their center line in manufacturing process of jamming action,and this model was further used to predict equivalence elastic constant.Firstly,based on analyzing the braiding process,interior fiber bundle distribution of unit cell was established;then,the geometric position coordinates for fiber bundle jamming regions of improved unit cell model were derived with alternately changed circular and elliptical fiber bundle cross-section,assuming the original circular cross-section is squeezed into oval shape ellipse in pinch regions,thus curling the fiber bundle paths.Mathematical relationship between braiding parameters and unit cell geometric dimensions was also deduced,with a relative calculation error for braiding pitch length less than 4%compared with test data,which is better than those models ignoring fiber bundles＇ deformation.Finally,equivalence elastic constants were predicted,further used to investigate the effects of braiding angle and fiber volume fracture to elastic constants.

关 键 词：复合材料 三维四向编织 纤维束挤压变形 单胞模型 细观力学有限元法 宏观弹性常数 

分 类 号：TB330.1[一般工业技术—材料科学与工程]