This paper investigated the modeling and free vibration characteristics of a spinning graphene nanoplatelet (GPL) reinforced porous nanocomposite blade. The blade is made of porous foam metal matrix reinforced with graphene nanoplatelets (GPLs). Several different GPL distributions and porosity distributions in the blade are taken into account. The effective material properties of the blade, determined via the open-cell scheme, the Halpin-Tsai model, and the rule of mixture, are assumed to be varying continuously along the its thickness direction. According to the Kirchhoff’s plate theory, the governing equations of the spinning blade are derived by adopting the Hamilton principle. On the other hand, the non-uniform spinning blade is modeled by the finite element method which is compared with the theoretical method. The theoretical results match very well with the finite element ones obtained from ANSYS. Particular focus is given to the effects of the spinning speed, porosity coefficient, distribution pattern of GPLs and porosities, GPL weight fraction, length-to-thickness ratio and length-to-width ratio of GPLs, blade length, and spinning radius on the free vibration performance of the blade rotor.
In order to study the rubbing of the mistuned bladed disk system with variable thickness blades, an elastically supported shaft-variable thickness blades coupled finite element model is established in this paper. A new rubbing force model is proposed considering the variable thickness section characteristics and rotation effect of the variable thickness blade. A method of mistuned parameter identification is introduced which consists of static frequency testing of blades, dichotomy, and finite element analysis. Based on the finite element method, the mistuned bladed disk system is made dynamic analysis in full rubbing by applying the judgment load method. The dynamic response of the mistuned bladed disk system is discussed under different conditions. The results show that increasing the amount of mistuning will increase the system vibration. At high speeds, the impact force will be partially offset by centrifugal force. And the rubbing gap affects the form of rubbing. With the gap decreases, the system will change from intermittent rubbing to continuous rubbing. In addition, when the system is rubbed, due to energy dissipation and blade damping, the stress is transferred from the blade tip to the blade root and attenuated. In general, rubbing is a random complex nonlinear vibration process.
Plates are commonly used in many engineering disciplines, including aerospace. With the continuous improvement in the capacity of high value-added airplanes, large transport aircrafts, and fighter planes that have high strength, high toughness, and corrosion resistance have gradually become the development direction of airplane plate structure production and research. The strength and stability of metal plate structures can be improved by adding reinforced materials. This paper studies graphene platelets (GPLs) reinforced with a free vibration porous composite plate. The porous plate is constructed with a multi-layer model in a metal matrix containing uniform or non-uniformly distributed open-cell internal pores. Considering the random and directional arrangement of graphene platelets in the matrix, the elastic modulus of graphene composites was estimated using the Halpin–Tsai micromechanical model, and the vibration frequencies of graphene composite were calculated using the differential quadrature method. The effects of the total number of layers, GPL distribution pattern, porosity coefficient, GPL weight fraction, and boundary conditions on the free vibration frequency of GPLs reinforced porous composite plates are studied, and the accuracy of the conclusions are verified by the finite element software.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.