Numerical predictions of 3‐D filler orientation and elastic compliance for reinforced plastics containing fillers with aspect ratio distribution

Abstract In the injection molding of parts containing 30 wt% short‐glass‐fiber or glass‐flake, filler orientation distribution functions and elastic constants are predicted, taking into account the aspect ratio distribution of fillers. The filler orientation distribution functions and the elastic compliance tensors are estimated by using Advani's method and Wakashima's method, respectively. The estimated filler orientation distributions in composite parts reinforced with short‐glass‐fiber or glass‐flake agree with soft X‐ray photograph observations. The fiber orientation distribution function, predicted for interaction coefficient C _I = 0.01, is close to the experimental results. Based on this orientation distribution, the elastic compliance tensor distributions are predicted on the assumption that the filler aspect ratio can be presented by a circumscribed filler aspect ratio or an equivalent filler aspect ratio. As a result, the vibration behavior predicted by adopting the equivalent aspect ratio agrees with the experimental results. Polym. Compos. 25:194–213, 2004. © 2004 Society of Plastics Engineers.