Effect of fiber orientation on the strength of thermoplastic composite tubes subject to four-point bending

This paper presents a study on the effect of fiber orientation on the strength of thermoplastic composite tubes made by automated fiber placement. The tubes are subjected to four-point bending deformation, representing the loading conditions in helicopter landing gears. The methodology for the study consists of the development of a finite element model for two particular tubes that yields results matching those from experiments. Maximum stress criterion is used for the determination of failure. The finite element model is then used to study the stress distribution and final failure and elongation of tubes with different layers with different fiber orientations. The lay-up sequence that can provide maximum failure load is then determined.