In this paper, an alternative approach in operational modal analysis is presented, utilizing image processing technique and transmissibility functions. Imaging sensors do not impose additional mass on the structure due to their non-contact nature, while transmissibility functions, independent of excitation type, can directly extract mode shapes. The innovation of this research lies in combining these two techniques to record dynamic responses and identify modal properties. To capture the temporal response history from video signals, the block-matching method with sub-pixel accuracy was employed. Validation was conducted by recording the response of the tip of a CANTILEVERed steel beam subjected to impact excitation, using a high-speed camera and a laser vibrometer, simultaneously. The RMSE plots in the time domain and the PSD in the frequency domain indicate high accuracy of this method. Using this approach, the displacement time histories of various points on the structure were extracted from the video signals, and the modal properties, including natural frequencies, damping ratios, and mode shapes, were identified using the transmissibility matrix method. The results obtained from the proposed method were compared with the stochastic subspace identification (SSI) method and analytical solutions. The findings reveal the accuracy of the modal identification approach introduced in this article. The highest relative error in estimating the natural frequencies of the first and second modes, compared to the values from the laser method, are 0.19% and 0.13%, respectively, and in comparison to the analytical values, they are 0.34% and 1.5%, respectively.

Vibration energy harvesting with piezoelectric material can currently generate up to 300 microwatts per cubic centimeter, making it a viable method of powering low-power electronics. A problem in piezoelectric unimorph energy harvesting is to generate the most power with limits in system mass. This paper studies the effect of a piezoelectric bimorph CANTILEVER beam harvester shape on its electromechanical performance. A semi-analytical mechanical model was developed using Rayleigh–Ritz approximations for piezoelectric energy harvester with tapered bimorph CANTILEVER beam. A coupled field simulation model for the harvester is constructed using MATLAB and ABAQUS software to study the effect of varying the length and shape of the CANTILEVER beam to the generated voltage and verification study is performed. Design optimization on the shape of the harvester is done to maximize output power. It is shown that tapered beams lead to a more uniform strain distribution across the piezoelectric material and increase the harvesting performance.

This research explores a novel technique for precise mass sensing, involving the detection of an object's position and mass when affixed to a flexoelectric CANTILEVER Euler-Bernoulli microbeam. Third-order relation of the curvature is considered to obtain the nonlinear governing equations and the related boundary conditions, from Hamilton’s principle on the basis of size-dependent piezoelectricity theory. The Galerkin method is employed to discredit the partial differential equation of motion into ordinary differential equations. The Lindstedt-Poincare technique is employed to derive a concise mathematical expression that describes the frequency alteration resulting from the presence of a concentrated mass on the microbeam's exterior. By applying direct current voltage, the natural frequency shift of the flexoelectric CANTILEVER Euler-Bernoulli microbeam under an added mass is examined. Finally, after validation of the results, the effects of size-dependent parameters, input voltage, and flexoelectric coefficient on static deformation and frequency behavior are shown. It can be found that the maximum sensitivity for l/h = 0.0 is at V0 = 2600v, By adjusting the material length scale factor relative to the beam thickness ratio, the sensitivity is observed to diminish. Also, by increasing the position of the added mass, the sensitivity is decreased and, where the flexoelectric effect is small, the increment in the position of added mass decreases the first and second frequency shift.

Energy harvesting from ambient vibrations using piezoelectric CANTILEVERs is one of the most popular mechanisms for producing electrical energy. Recently, efforts have been made to improve the performance of energy harvesters. The output voltage dramatically depends on the geometrical and physical parameters of these devices. In addition, improved performance is often achieved by operating at or near the resonance point. So, this paper aims to reduce the natural frequency to match the environmental excitation frequency and increase the harvested energy. For this purpose, different geometrical and physical parameters are studied to determine the impact of each parameter. These parameters include the length, thickness, density, and Young’s modulus of each layer. The beam is considered a unimorph CANTILEVER with rectangular configuration and the study is performed using COMSOL Multiphysics software. The results are compared with those obtained by an analytical approach. The results show that changing the parameters made the natural frequency of the system vary in the range of 20 Hz to 200 Hz and increased the output voltage up to 20 V.

Dolphin Echolocation Optimization (DEO) is a newly developed meta-heuristic optimization method inspired from dolphin’s rules for searching their environment. In this paper, reinforced CANTILEVER retaining walls are designed by DEO. Results show that DEO not only leads to better results in comparison to the previously utilized algorithms but also optimality curves achieved with this method provides the engineers better understanding of the design.

In recent years, Atomic Force Microscopy (AFM) has been known as a powerful and efficient tool for surface imaging in different environment. To enhance image quality and more precise prediction of Micro-CANTILEVER (MC) behaviour, accuracy in the MC modeling and simulation and detecting the MC sensitivity to geometric parameters has great importance. To model the vibration motion of the AFM non-uniform piezoelectric MC, Timoshenko beam theory is used in order to consider the effect of shear effect in air and liquid environment. In addition, the effect of the forces imposed by the ambient and sample surface is considered. Frequency response has been studied in the air and different liquid environments and the obtained results have been compared with experiential results as well as with results obtained from Euler-Bernoulli beam theory that is reflective of higher precision exercised in the modeling in respect to Euler-Bernoulli beam theory. Efast statistical method, which is found efficient and quick in the survey of linear and nonlinear models and takes the inter-parameter coupling effect into consideration besides calculating the sensitivities unique to each of the factors, has been applied in order to analyse the geometrical parameters’ effects on the MC natural frequencies in the air and water environments.