A dual-scale homogenization method to study the properties of chopped carbon fiber reinforced epoxy resin matrix composites

In this work, a dual-scale homogenization (DSH) procedures including the representative volume element (RVE) and Unit cell (UC) with Halpin-Tsai models in the UC scale and space direction-sensitive Hotelling expansion (SDSHE) models in RVE scale separately. These two methods are introduced and implemented to predict the response of effective elastic properties in chopped fiber reinforced epoxy matrix structures. A post-processing scheme of subdomain in UC scale based on Gauss theorem is proposed in SDSHE method, which is used to extract the average strain and stress in UC three-dimensional structure. In addition, the X-ray computed tomography was used to determine the fourth order tensor orientation angle and the probability distribution information of chopped fiber length in testing samples. Homogenization properties in RVE scale, and inclusion volume fraction (VF), thickness of interface and orientation tensors are designed in UC scale and compared. The excellent correlations with experiments prove the effectiveness of the proposed models. Furthermore, the algorithm proposed in this paper realizes the homogenization of the two scales in the process of numerical analysis, and it will effectively take into account many problems that cannot be achieved by other algorithms, such as the path strain of the model, the thickness of the interface, and so on.

Automated summary

In this work, a dual-scale homogenization procedure was used to predict the response of effective elastic properties in chopped fiber reinforced epoxy matrix structures. Two methods, representative volume element (RVE) and unit cell (UC), were introduced and implemented at different scales. The average strain and stress in the UC three-dimensional structure were extracted using a post-processing scheme based on Gauss theorem in the space direction-sensitive Hotelling expansion (SDSHE) model. X-ray computed tomography was used to determine the orientation angle and probability distribution information of chopped fiber length. The proposed models showed excellent correlations with experiments, proving their effectiveness.