Fiber orientation measurement of fiber injection molded nonwovens by image analysis

Abstract

The fiber injection molding process is an innovative approach for the manufacturing of long fiber nonwoven preforms with little to no waste. An important property for the mechanical characteristics of the composite parts is the fiber orientation of the fiber injection molded nonwovens. In this paper a newly developed assemble method based on Fast Fourier Transform and improved Structure Tensor methods for the computation of the fiber orientation distribution in the local orientation by image analysis of transmitted light images is presented. For the computation of the fiber orientation, the Fast Fourier Transform and Structure Tensor methods are used. The new method is evaluated using simulated images and transmitted light images of real nonwovens to evaluate their accuracy. The computed fiber orientation distributions are compared to reference distributions by means of the Kullback–Leibler divergence. It is shown that the assemble method can perform accurate and reliable measurement of fiber orientation measurement and the modified Structure Tensor method improves results significantly compared to the current state of the art.