Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
Structural analysis of a filament wound rocket motor casing under internal pressure
Submission Author:
Erika Tomita , DF
Co-Authors:
Erika Tomita, Artem Andrianov
Presenter: Erika Tomita
doi://10.26678/ABCM.COBEM2021.COB2021-1749
Abstract
This work presents a preliminary evaluation of a failure load for the filament wound carbon/epoxy composite casing without metal liner by finite-element method. The main objective of the work is to obtain and verify a numerical model of the composite casing comprising cylindrical part and hemispherical domes with equal polar openings in conditions of a hydrostatic test. In order to achieve the objective, the lamination parameters such as winding angle, stacking sequence and thickness distribution in the dome are determined for a particular geometrical configuration of the casing. The winding angle is obtained from Clairaut's equation that considers the geodesic trajectory of the fiber on shells of revolution. Both symmetric and non-symmetric balanced configurations are considered for the stacking sequence. The thickness distribution in the dome is evaluated by a so-called flat solution. The numerical model of the casing under internal pressure is validated by evaluation of the hoop strain in the center of the cylindrical part and its comparison with hoop strain calculated by classical lamination theory. The first ply failure (FPF) is determined for various stacking sequences of the laminate by maximum stress criteria. The minimal required thickness of the casing is computed by netting theory where the matrix properties are ignored. For this, the longitudinal mechanical properties of the wound unidirectional laminate are measured by a standard ASTM method. The fiber volume ratio in the wound test specimens is evaluated by an optical technique. As expected, the stacking sequence has no significant influence on the failure behavior of the composite casing. Thus, the technological process of filament winding dictates the stacking sequence of the casing. Continuous process of filament winding implies the non-symmetric balanced configuration with angle-ply layers at the beginning and the hoop layer at the end. A leakage of the manufactured test casing is expected to occur rather than the burst failure with fiber fractures, because FPF predicts transverse stress failure of the lamina and the minimal thickness evaluated by netting theory is of the order of the wound ply thickness.
Keywords
structural analysis, Finite Element Analysis, filament winding, composite rocket case
