Deriving unidirectional lamina properties from testing on cylindrical laminated specimens

• Published in: Composite structures 2020-08, Vol.245, p.112382, Article 112382
• Main Authors: Ataabadi, P.B., Karagiozova, D., Shaterzadeh, M.H., Alves, M.
• Format: Article
• Language: English
• Subjects: Laminate properties; Material characterization; Non-flat specimens; Shear fixture; UD lamina properties
• ISSN: 0263-8223; 1879-1085
• DOI: 10.1016/j.compstruct.2020.112382

The present work aims to derive the mechanical properties of a unidirectional (UD) lamina from experimentally measured properties of non-flat (cylindrical) laminated specimens. The specimens were cut from carbon fiber-epoxy tubes having cross-ply and angle-ply layup configurations. Special tests were designed and applied on these specimens to measure the mechanical properties of the laminate, Ex, Ey, νxy, Gxy, as well as tensile and shear failure strength. By using the classical laminate theory (CLT), the mechanical properties of UD lamina, E1, E2, ν12 and G12 were expressed explicitly as functions of the measured properties of the cross-ply laminate and in form of effective mechanical properties of general lamination configuration like the angle-ply layup. A new shear test fixture was designed in order to obtain the in-plane shear modulus and shear strength of ring-shaped composite specimens. This shear test fixture has proved to be advantageous, especially when one bears in mind that there are very few shear test methods for cylindrical components. The outcomes of this work would be useful for material characterization and quality control when standard flat coupons are not available.