Clamped-free (cantilever) beams have practical applications. For example, it is not possible to use normal means to determine the modulus of elasticity for thin films. However, the film material can be deposited onto the beam substrate by sputtering or by applying the additive manufacturing technique and thereby change the beam’s stiffness as suggested by Dias da Silva et al . The stiffness change causes a shift in the natural frequencies of the vibration of the beam and this shift can be used to determine the material properties of the film.
This study provides four methods of analysis: 1) formula calculation, which is used as the benchmark, 2) finite element method, 3) experimental method with accelerometer, and 4) experimental method with condenser microphone. Theoretical results are used as benchmarks and compared with the finite element method (FEM) and two experimental methods (accelerometer and condenser microphone). The challenge is to obtain results with the necessary accuracy (significant digits) at higher resonant frequencies of vibration. The two experimental methods were evaluated and the experimental method with condenser microphone showed the most promise for future work. Very little was found in the literature regarding the use of a condenser microphone to measure resonant frequencies.