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Critical in-plane load versus the ratio of length to thickness L/h with different temperature fields.
Source publication
In this paper, static and dynamic stability analyses taking axial excitation into account are presented for a laminated carbon fiber reinforced polymer (CFRP) cylindrical shell under a non-normal boundary condition. The non-normal boundary condition is put forward to signify that both ends of the cylindrical shell are free and one generatrix of the...
Context in source publication
Context 1
... is because increasing the ratio of radius to thickness and the temperature field can lead to a decrease in the stiffness of the system. The curves of critical in-plane load versus the ratio of length to thickness L/h with different temperature fields are shown in Figure 3. One can find that the critical static in-plane load decreases while the ratio of length to thickness or the temperature field increases. ...
Citations
... The partial differential governing equations with axial excitation of the vibrating micro-gyroscope are derived via the extended Hamilton's principle in both drive and sense directions. Then the Galerkin technique is used to truncate the partial differential governing equations to ordinary differential equations (Chen et al. 2020(Chen et al. , 2021Yang et al. 2021Yang et al. , 2022Yang et al. , 2023. The frequency/force amplitude response curves of the vibrating beam micro-gyroscope are studied by utilizing the multi-scale method and numerical continuation technique. ...
In this paper, the nonlinear vibration characteristics of vibrating beam micro-gyroscopes subject to electric and piezoelectric actuation are studied. The comprehensive nonlinear model including nonlinearity in curvature, inertia and electrostatic force is considered. In the research of electrostatically actuated micro-gyroscopes, it’s a novel way to tune the primary resonance by piezoelectric actuation and nonlinearity in curvature and inertia. The multiple scales method and numerical continuation technique are employed to characterize the frequency-amplitude and force-amplitude responses of the micro-gyroscope. The effect of the size-dependent, fringing field, external excitation, angular speed, piezoelectric DC voltage and nonlinearity in curvature and inertia on the nonlinear dynamic responses of the micro-gyroscopes is investigated in detail. The frequency-response results show that the small vibration produces a symmetrical frequency response curve in sense direction, while the system actually has significant softening characteristics in drive direction. The nonlinear multi-value problem is effectively reduced in sense direction under the size-dependent effect, which plays an important role in the design of detection instruments for micro-gyroscopes. Choosing a positive piezoelectric DC actuation voltage will obtain a higher sensitivity. Increasing the curvature nonlinearity and reducing the inertial nonlinearity of the gyroscopic system will help the micro-gyroscope obtain better sensitivity, and may eliminate multi-valued responses as much as possible.
... Melaibari et al. [31] examined analytically the dynamic behavior of randomly oriented FG-CNTRC laminated shells with different geometries. Yang et al. [32] investigated the static and dynamic stability analyses of an FG-CRNC cylindrical shell subjected to a non-normal boundary condition with one generatrix clamped. ...
Coated functionally graded materials (FGMs) are used in several industrial structures such as turbine blades, cutting tools, and aircraft engines. Given the need for analytical and numerical analysis of these complex structures, a mathematical model of tricoated FG structures is presented for the first time in this paper. The objective of this work was to analyze analytically the buckling problem of unidirectional (1D), bidirectional (2D), and tridirectional (3D) coated FG spherical nanoshells resting on an orthotropic elastic foundation subjected to biaxial loads. Based on the generalized field of displacement, a 2D higher-order shear deformation theory was proposed by reducing the number of displacement variables from five to four variables for specific geometry cases. The nonlocal strain gradient theory was employed to capture the size-dependent and microstructure effects. The equilibrium equations were performed by applying the principle of the virtual work, and the obtained differential equations were solved by applying the Galerkin technique to cover all possible boundary conditions. The proposed elastic foundation was defined based on three parameters: one spring constant and two shear parameters referring to the orthotropy directions. A detailed parametric analysis was carried out to highlight the impact of various schemes of coated FGMs, gradient material distribution, length scale parameter (nonlocal), material scale parameter (gradient), geometry of the nanoshell, and variation in the orthotropic elastic foundation on the critical buckling loads.
Axially moving wing aircraft can better adapt to the flight environment, improve flight performance, reduce flight resistance, and improve flight distance. This paper simplifies the fully unfolded axially moving wing into a stepped cantilever plate model, analyzes the structural nonlinearity of the system, and studies the influence of aerodynamic nonlinearity on system vibration. The model is affected by aerodynamic forces, piezoelectric excitation, and in-plane excitation. Due to Hamilton’s principle of least action, the mathematical model is established based on Reddy’s higher-order shear deformation theory, and using Galerkin’s method, the governing dimensionless partial differential equations of the system are simplified to two nonlinear ordinary differential equations, and then a study of the influence of the various engineering parameters on the nonlinear oscillations and frequency responses of this model is conducted by the method of multiple scales. It was found that the different values of a5, a6, b6 and b8 can change the shape of the amplitude–frequency response curve and size of the plate, while different symbols a7 and b7 can change the rigidity of the model. The excitations greatly impact the nonlinear dynamic responses of the plate.
In this paper, the influence of aerodynamic prestress on vibration characteristics of mistuned blisk is investigated by comparative study considering one-way fluid–structure interaction. It is found that the aerodynamic prestress changes twisted angle of the blade, increases natural frequencies of the mistuned blisk and affects the sensitivity of natural frequency to rotational velocity. To facilitate the mechanism study of these phenomena, a simplified blade model with chordwise variable thickness is established. The effects of Young’s modulus, rotational velocity and pre-twisted angle on natural frequency are investigated by the first-order shear deformation plate theory and Chebyshev–Ritz method. The results show that the natural frequency of the blade is positively correlated with the rotational velocity and pre-twisted angle. For different twisted angles, the same rotational velocity change can cause different natural frequency increments. In addition, the aerodynamic prestress can suppress the effect of Young’s modulus mistuning on natural frequency.
