TY - JOUR
ID - 4704
TI - Free Vibration of Axially Functionally Graded Tapered Micro-Beams Considering Uncertain Properties
JO - AUT Journal of Civil Engineering
JA - AJCE
LA - en
SN - 2588-2899
AU - Kamali, Farhad
AU - Shahabian, Farzad
AD - Civil Engineering Department, Ferdowsi University of Mashhad, Mashhad, Iran.
Y1 - 2021
PY - 2021
VL - 5
IS - 4
SP - 543
EP - 556
KW - Axially functionally graded
KW - Micro-beam
KW - Size-dependent behavior
KW - Modified Couple Stress Theory
KW - First-Order Second-Moment technique
KW - Reliability Index
DO - 10.22060/ajce.2022.18056.5657
N2 - Experimental observations reveal that the classical continuum theory cannot accurately describe the mechanical behavior of micro/nanoscale structures. In fact, the size-effect will arise when the order of structure dimensions is the same as the material characteristic length. The current work presents free vibration and stability of axially functionally graded (AFG) tapered micro-beams with random properties. The size-dependent behavior of the micro-structure is modeled by the modified couple stress theory. The mathematical formulations are developed based on the Euler-Bernoulli beam model and von Kármán geometric nonlinearity. The minimum total potential energy principle is employed to obtain governing differential equations and the corresponding boundary conditions. The governing equations are solved by the Galerkin method. Due to the complexity of the fabrication process of FGMs, their mechanical and structural properties may vary from sample to sample significantly. Hence, achieving the desired FGMs specification is almost impossible and they are not deterministic, inherently. To incorporate uncertainties in the mathematical model of this study, a First-Order Second-Moment (FOSM) technique is applied to estimate the reliability index of the micro-structure, stochastically. Finally, numerical examples are presented for both deterministic and reliability analysis to show the effects of geometry, length scale parameter, material distribution, and axial load on the natural frequency of vibration and the reliability index of the AFG tapered micro-beam. It can be concluded that by increasing the coefficient of variation (COV) of random variables, the reliability index will decrease. Indeed, by enhancing the length scale parameter, a higher natural frequency of vibration is expected.
UR - https://ajce.aut.ac.ir/article_4704.html
L1 - https://ajce.aut.ac.ir/article_4704_ad4b8fe8a4b97eed5abbd2209ab3e66c.pdf
ER -