حسانه خسروابادي

This study presents the analysis of linear vibrations of sandwich beams with a concentrated mass at the end and a honeycomb core, featuring an adjustable Poisson's ratio. Utilizing the first-order shear deformation theory and Hamilton's principle, a system of coupled linear partial differential equations representing the motion equations is derived. These equations are numerically solved using the Generalized Differential Quadrature (GDQ) method in MATLAB software, from which the linear bending natural frequencies and mode shapes are extracted. A parametric study eva‎luates the impact of geometric and mechanical parameters such as the dimensions and parameters of the honeycomb cell, layer thicknesses, length, axial load, and types of boundary conditions on linear vibrations. In addition to frequency domain analysis, time-domain analysis is also conducted by considering a harmonic base excitation with various frequencies. Frequency domain analysis reveals that using honeycomb structures significantly reduces the mass of the structure while the frequencies remain nearly constant or increase. Additionally, employing an auxetic core allows for control over the beam's oscillation amplitude; therefore, a multi-objective genetic algorithm is used considering objective functions including minimizing the difference between the oscillation amplitude and the allowable range, and minimizing the ratio of the force transmitted to the concentrated mass to the amplitude of the force applied to the structure due to base excitation. The structure's optimized behavior in terms of the physical and geometrical properties of the auxetic layer is presented. The results are validated using finite element simulation of the structure and corroborated by authoritative references.

ارتعاشات خطي , تئوري تغييرشكل برشي مرتبه اول , جاذب ارتعاشي فراسازه‌اي , آگزتيك لانه‌زنبوري , بهينه‌سازي چندهدفه

Linear vibrations , first-order shear deformation theory , Meta-structural vibration absorber , honeycomb Auxetic , Multi-objective optimization

hesaneh khosroabadi

dr. roohollah talebi tooti