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Designing multimodal and multidirectional energy harvester (EH) topologies with high-strain areas is among the most demanding and critical obstacles encountered in powering small electronics and wireless sensor networks. These deficiencies are highly considerable by utilizing the conventional cantilever beam EHs. In order to overcome these challenges, effective structural design is required. In this paper, two different 3D asymmetric skeletal frame topologies are designed and introduced for energy harvesters. The vibrational behaviors of the proposed structures are investigated using finite element method and compared to corresponding 1D beam and 3D symmetric frame topologies. Furthermore, the electromechanical responses of the aforementioned EHs are obtained showing the advantages in more detail. The results imply that the asymmetric frames can simultaneously solve the main problems of EHs in a successful manner.

One of the most complicated challenges in submarine rescue operations is how to effectively connect a disabled submarine to a rescue one. Articulated transfer skirt mechanisms are utilized as a means for simplifying the connection process between two submarines. The accuracy of kinematic procedures used for adjusting the mechanism is a substantial aspect of designing transfer skirts. This article commences with investigating forward kinematics of the transfer skirt. Afterwards, its inverse kinematics is taken into consideration using data provided by four altimeter sensors located on the skirt mouth. An appropriate algorithm is presented for the rotation required by both direction and angle skirts based on data obtained by altimeter sensors. Furthermore, a process is designed to obtain new set points if there exists errors in the control system of the skirt or for any changes in the orientation of disabled submarine or rescue submarine. Finally, the results are validated using CATIA DMU Kinematics.

In this paper, the vibrational behavior of a functionally graded (FG) micro-resonator is investigated for three different configurations based on the Euler-Bernoulli beam model and the Von Karman nonlinear strain assumption. The three configurations include: (1) an FG micro-resonator with a fixed foundation, (2) piezoelectric layers added to the first model, and (3) a second fixed foundation added to the first model. These investigations are performed under the effect of electrostatic forces, the forces caused by the deformations of piezoelectric layers due to the applied voltage, Casimir forces, and uniform temperature changes. The equations governing the vibrational behaviors are obtained using the Hamilton's principle and the modified couple stress theory. Static deformations and the fundamental vibrational mode are calculated using the differential quadrature method in the spatial domain for all three configurations. Furthermore, the dynamic equations are obtained from the Galerkin discretization and solved with multiple time scales technique. The results show that the frequency behavior of a micro-resonator can be adjusted using the three models.

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