Modelling of fibre steered plates with coupled thickness variation from overlapping continuous tows

Previous research has hinted on further improvements of the buckling behaviour of variable-stiffness laminates by incorporating overlaps, resulting in a variable thickness profile that is non-linearly coupled to the steering angles. The present study compares two modelling strategies to consider the variable thickness distribution: 1) as-manufactured with discrete thicknesses; and 2) smoothed with a continuous thickness distribution. The asmanufactured discrete thickness created by overlapping tows is obtained by means of virtually manufactured laminates. The smeared approximation is much simpler to implement, whereby the local thickness is a nonlinear function of the local steering angle. Linear buckling analyses are performed by means of fast semianalytical models based on the Ritz method using hierarchical polynomials and classical plate formulation. By assuming a smooth manufacturing mould on one side, a one-sided thickness variation is produced, resulting in non-symmetric laminates for which the mid-plane surface is varied accordingly. Modelling guidelines are provided regarding the use of the smeared model in a study covering a wide range of geometries, loading and boundary conditions. With these guidelines, one can apply the smeared thickness technique in semianalytical models to reach a correlation within +/- 5% compared to a costly discrete-thickness finite element model.

Automated summary

Previous research has suggested that incorporating overlaps in variable-stiffness laminates can further improve buckling behavior. This study compares two modeling strategies for considering variable thickness distribution: discrete thicknesses and continuous thickness distribution. By utilizing virtually manufactured laminates and a smoothed manufacturing mold, the study examines the effects of variable thickness on buckling analyses.