摘要
针刺陶瓷基复合材料在航空航天等热端结构上具有广泛应用前景,但在预制、沉积等过程中产生的制造缺陷导致其性能分散性大,难以准确预测其力学行为。本文基于X射线显微镜和三维图像重构技术,结合概率拟合方法,对材料孔隙缺陷的尺寸和结构特征进行参数化表征,发现与单向层相比,网胎层孔隙率高,且孔隙等效直径大,但长宽比小。采用椭球拟合和多尺度建模方法,对材料的弹性性能进行了预测和分析,预测结果与实验结果相差约3.1%,具有较好的准确性。通过对孔隙参数的讨论发现:单向层孔隙在分布方向上具有较好的统一性,对纤维束长度方向弹性性能的削减程度低于对其他方向弹性性能的削减程度;相较而言,网胎层具有较高的孔隙率,通过改善工艺参数降低网胎层孔隙率,有利于进一步提高材料整体的弹性性能。
Needled-punched ceramic matrix composites are promising for a wide range of applications in hotend structures in aerospace field.However,the manufacturing defects causing in the process of pre-fabrication and deposition lead to a high degree of dispersion in their properties.It is difficult to accurately predict their mechanical behavior.A sub-regional parametric characterization method for pore defects in needle-punched ceramic matrix composites was proposed based on X-ray microscopy and 3D image reconstruction techniques.Combined with the idea of probabilistic fitting,the size and structural characteristics of the material pore defects were parametrically characterized,and it was found that the equivalent diameter of the pores in the fiber-web layer was larger than that in the unidirectional layer,but the aspect ratio was smaller than that in the unidirectional layer.The elastic properties of the materials were predicted and analyzed using ellipsoid fitting and multiscale modelling methods,and the predictions differed from the experimental results by about 3.1%with good accuracy.The discussion of pore parameters revealed that:the unidirectional layer porosity has better uniformity in the distribution direction,and the reduction of the elastic properties in the direction of the fiber bundle length is lower than that in the other directions;in comparison,the fiber-web layer has higher porosity,and it is beneficial to reduce the porosity of the fiber-web layer to further improve the overall elastic properties of the material by improving the process parameters.
作者
孙士勇
李海林
王俊龙
SUN Shiyong;LI Hailin;WANG Junlong(School of Mechanical Engineering,Dalian University of Technology,Dalian 116024,China)
出处
《复合材料科学与工程》
北大核心
2025年第4期20-27,67,共9页
Composites Science and Engineering
基金
国家自然科学基金(51790173)。
关键词
针刺陶瓷基复合材料
X射线显微镜
孔隙缺陷表征
多尺度建模
弹性性能
needle-punched ceramic matrix composites
X-ray microscopy
characterization of pore defects
multiscale modelling
elastic properties
作者简介
第一作者:孙士勇(1981-),男,博士,副教授,博士生导师,研究方向为先进复合材料结构设计制造与表征,sunshy@dlut.edu.cn。
