Fractal interpolation-based micro-surface reconstruction method for composite pore walls

基于分形插值的复合材料孔壁微观表面重构方法

¹ School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an 710072, China
² AVIC Shaanxi Aircraft Industry Group Company Ltd, Hanzhong 723099, China

Received: 27 September 2022

Abstract

The pore wall morphology of carbon fiber reinforced composite (CFRP) laminates is one of the key factors to determine their service performance. However, due to the direction angle of the material fibers, the original micro surface morphology of the pore wall is complex and difficult to characterize. In this paper, a method to reconstruct the micro surface of the hole wall by fractal interpolation is proposed. By using a small number of data points extracted, the high-precision equivalent micro surface by fractal interpolation can be reconstructed, which can effectively characterize the composite joint surface. Firstly, the geometric features of micro surface are extracted by using the experimental measurement. Then, based on the model for fractal interpolation, an improved self affine fractal interpolation algorithm is used to reconstruct the original measured surface. Finally, the geometric and mechanical validity of fractal interpolation surface reconstruction is verified by combining geometric model and finite element model. The results show that when the sampling interval is 3~5, the geometric error and mechanical property error of the fractal interpolation method are below 10%, which can effectively characterize the original composite joint surface.

摘要

碳纤维增强复合材料(CFRP)层合板连接结构的孔壁形貌是决定其服役性能的关键因素之一, 但受到材料纤维方向角的作用, 其孔壁的原始微观表面形貌复杂且难以表征。提出了一种利用分形插值进行孔壁微观表面重构的方法, 利用提取的少量数据点, 分形插值重构出高精度的等效微观表面, 从而有效表征复合材料连接表面。利用实验测量的方法, 进行微观表面几何特征提取; 基于分形插值数学模型, 运用改进的自仿射分形插值算法, 对原始实测表面进行分形插值重构; 结合几何模型和有限元模型, 验证了分形插值重构表面的几何与力学有效性。结果表明: 当采样间隔选取3~5时, 分形插值方法的几何误差与力学性能误差均小于10%, 可以有效表征原始复合材料连接表面。