Research Information System
1 st International Conference on Applied Engineering and Natural Sciences (ICAENS2021), Konya, Turkey, 1 - 03 November 2021, pp.150
In this paper, we present a computational investigation to study amplitude sensitivities to acoustic forces in a wide frequency range. We utilize bimodal, trimodal, and tetramodal excitation schemes for the actuation of the Atomic Force Microscopy (AFM) micro-cantilever in the presence of dynamic acoustic forces. In multimodal operations, the micro-cantilever is driven by applying external excitation forces at eigenmode angular frequencies. The Equation of Motion (EOM) is constructed in the consideration of the driven and damped harmonic oscillator as a model and solved numerically to obtain the deflections of the micro-cantilever at flexural eigenmodes. In this current work, time-domain responses of the micro-cantilever to acoustic forces are introduced for different excitation schemes so that free oscillations are compared with the oscillations of the driven micro-cantilever undergoing acoustic forces. Then, we evaluate the results of amplitude responses at the first four eigenmodes with respect to acoustic force frequencies for diverse force strengths. For our case, we obtain the amplitude response at the fourth eigenmode of around 0.303 nm for the force strength of 2900 pN at the frequency of 1740 kHz. This result proves that acoustic forces at megahertz frequencies are measured by using resonant AFM micro-cantilever under tetramodal operation. Therefore, multimodal excitation schemes can be applied to enhance the amplitude sensitivities to dynamic acoustic forces.