No abstract

No abstract

A new nonlinear finite element model is provided for the nonlinear flutter response of shape memory alloy (SMA) hybrid composite plates under the combined effect of thermal and aerodynamic loads. The nonlinear governing equations for moderately thick rectangular plates are obtained using first-order shear-deformable plate theory, von Karman strain-displacement relations and the principle of virtual work. To account for the temperature dependence of material properties, the thermal strain is stated as an integral quantity of thermal expansion coefficient with respect to temperature. The aerodynamic pressure is modeled using the quasi-steady first-order piston theory. Newton-Raphson iteration method is employed to obtain the thermal post-buckling deflection, while the linearized updated mode method is implemented in predicting the limit-cycle oscillation at elevated temperatures. Numerical results are presented to show the thermal buckling and flutter characteristics of SMA hybrid composite plates, illustrating the effect of the SMA volume fraction and pre-strain value on the aero-thermo-mechanical response of such plates.

The Magnetorheological fluid, as one of the smart materials, is the focus of many researches running nowadays and is getting to replace many materials in several engineering applications. This fluid is characterized by its ability to change from liquid into semi-solid gel in few milliseconds as a result of applying magnetic field. This paper deals with a magnetorheological fluid embedded in an Aluminum sandwich beam to give the whole sandwich structure relevant controllability of various parameters such as natural frequencies, vibration amplitudes, and damping factors. This paper presents Finite Element (FE) formulation of the MR sandwich beam, and uses the finite element model to solve for various beam boundary conditions, various magnetic field levels and configurations. The paper also compares the finite element results with published analytical results. Finally, the paper checks the suitability of the spectral element (SE) method in dealing with the MR sandwich beam, and compares the spectral results with the finite element results.

No abstract