On the dynamics of rotating cracked functionally graded blades reinforced with graphene nanoplatelets

•Vibration problem of a cracked rotating GPLRC blades is investigated.•The energy functional of the pre-twisted blades is obtained using FSDT.•Discrete equations of blades are derived using the IMLS-Ritz method.•Vibration characteristics of the blade are comprehensively investigated. This paper presents the dynamic analysis for a rotating pre-twisted functionally graded graphene nanoplatelets (GPLs) reinforced composite (GPLRC) blade with matrix cracks. The pre-twisted blade is composed of multiple composite layers reinforced with GPLs which are evenly distributed in each layer while the GPL weight fraction changes from layer to layer along the thickness direction. The effective materials properties are predicted by Halpin-Tsai micromechanics model for each GPLRC layer. The matrix cracks also distribute in each layer. Stiffness degradation of laminated composites due to matrix cracks is evaluated by the self-consistent model. The energy functional of rotating pre-twisted GPLRC blades are obtained using the first-order shear deformation theory. Based on the IMLS-Ritz approximation, the discrete vibration equations of rotating pre-twisted GPLRC blades are derived. The accuracy of the IMLS-Ritz results is examined by comparing the natural frequencies with those presented in the previously published papers. Then the vibration characteristics influenced by the crack density parameter, GPLs parameters, rotating speed, pre-twisted angle, presetting angle, and aspect ratio of the matrix cracked rotating pre-twisted GPLRC blades are firstly presented.