Multi-scale strength and buckling analysis of 3D woven composite spherical shells subjected to hydrostatic pressure

Abstract

3D woven composites are considered as the ideal materials for subsea pressure shells owing to their exhibit excellent out-of-plane properties of delamination resistance and compressive damage resistance, which greatly improves the bearing capacity of the structure. This paper presents the influence of the radius-to-thickness ratio and the initial defects on the 3D woven composite spherical shells subjected to external hydrostatic pressure using the multi-scale finite element and theoretical methods. Two kinds of typical 3D woven structures, curved shallow-crossing linking 2.5D, and straight shallow-crossing linking 2.5D, are selected. The results show that the proposed multi-scale finite element method is capable of accurately predicting the strength and buckling behavior of 3D woven composite spherical shells under external hydrostatic pressure loadings, validated by the comparison of theoretical predictions. Furthermore, the fabric structures, radius-to-thickness ratio, and initial defects affect importantly the mechanical behavior of 3D woven composites pressure shells.

Multi-scale modelling of the damage behavior for 3D woven composites with variant structure

“…The tow [1,11] replaces tow [1,10] to reach the position where tow [1,10] should be in the second step. The tow path [1][2][3][4][5][6][7][8][9][10] is longer than normal. The tow [1,9] is removed, and the adjacent tows [1,10] and [1,11] move to the left again and fill the corresponding vacancies.…”

“…Add the tow [1,17] in the corresponding vacancies. The tow path [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] is longer than the normal. In the third step, after the tow addition is completed, the 3DWF geometry becomes normal.…”

“…From the analysis above, it can be found that the directions of the 3DWF geometry do not change before or after tow reduction and addition, therefore, no obvious structural defects are induced near the variant region. After the first tow reduction, there will be the interval column path [1][2][3][4][5][6][7][8][9][10] and after tow addition, there will be the interval column path [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. After the second tow reduction and addition, the interval column path will disappear.…”

“…[1][2][3]. However, the geometry of 3DWC is usually complex in practical applications, such as turbine blade, radome, nozzle, etc [1,[3][4][5]. Especially when the cross-section of the composite component varies along the longitudinal direction, cutting the composite according to the designed dimensions is a routine method.…”

Beam element method for mechanical analysis of 2.5D woven composite: Modeling strategy and finite element method simulation

“…12 Therefore, multi-scale research method was proposed. The meso-level data were delivered to a macro-scale homogeneous composite component 13 to form a multi-scale simulation process. Multi-scale analysis sacrifices many details in the macro model.…”