Possibility of increasing the switching resource of liquid-metal self-regulating fuses with fusion insert

THE PURPOSE. Assessment of the state of the art in the development of current limiters based on liquid metal self-healing fuses and an increase in the switching life of self-healing fuses with a composite fuse-link.METHODS. When solving the problem, the method of literature analysis was used, as well as the method for calculating dependencies for different materials of the fuse-link, the implemented method of scientific computer mathematics.RESULTS. Literary sources contain information about the designs of liquid-metal self-healing fuses and their research, allowing conclusions to be drawn about their viability and the possibility of obtaining a practical yield. A common disadvantage of the of liquid-metal self-healing fuses design is a limited switching resource due to an increase in the diameter of the fuse-link under the action of arc erosion. A significant effect of increasing the switching resource and the stability of the protective characteristic is possessed by the design of a of liquid-metal self-healing fuses with a composite fusible link. However, in such designs, the switching capacity is reduced. It is shown that the main criterion for the operability of the liquid-metal self-healing fuses with a composite fusible link is the value of the ratio between the value of the shunting resistance and the resistance of the electric ARC. The performance of the liquid-metal self-healing fuses with a composite fusible link is ensured at values of this value below critical.CONCLUSION. The proposed mathematical expression may turn out to be useful in the development of liquid-metal self-healing fuses with a composite fusible link design, for example, when choosing an electrode material, liquid metal, etc. This will significantly increase the switching resource of the liquid-metal self-healing fuses with a composite fusible link. The condition must be taken into account in the parametric synthesis of the current limiter based on the liquid-metal self-healing fuses with a composite fusible link.

Wave Propagation in L-Shape Beams with Piezoelectric Shunting Arrays

Piezoelectric shunting arrays are employed to control the elastic wave propagation in L-shape beams. Unlike straight beams where longitudinal and flexural waves usually propagate independently, these waves are coupled in an L-shape beam. Based on transfer matrix method and Bloch theorem, dispersion curves and vibration transmissibility are evaluated and analyzed. A locally resonant gap is produced on the flexural and longitudinal waves, respectively, whose locations are nonoverlapped if the shunt damping is void. However, the longitudinal wave band gap can be completely overlaid by the flexural one when a proper shunting resistance is involved. With the decreasing of shunting inductance, the locations of longitudinal and flexural wave gaps both go up to higher frequencies which agree with the variation of resonant frequencies, but they are less affected by shunting resistance. As the resistance increases, the width of the band gaps grows, whereas the attainable maximum attenuation within the band gaps shows a significant decrease. Also, finite element simulations are performed to validate the numerical predictions, which demonstrate that the resulting transmissibility of displacements agree well with the band gaps.