The effect of electrolysis on the rate of corrosion of metals in photographic solutions

Abstract

A semi-active control approach is proposed to obtain a composite structures with tunable mechanical properties ranging from stiffer structure to better damper. To do this, we propose to apply an external electrical field to a piezoelectric polymeric matrix such as polyvinylidene fluoride (PVDF) reinforced with carbon nanotube. Depending on the magnitude and direction of electrical field, PVDF can be poled in the radial direction to align the electro-negative and electro-positive parts of molecular unit resulting in variable separation distance between piezoelectric polymer and nanotube. This leads to control of restriction effect of nanotube on the polymer segments, and consequently results in tunable interfacial adhesion between piezoelectric polymer and nanotubes with faster response time. Along this line and in order to present an analytical framework for such multifunctional composites, a shear-lag model is developed for nanotube-based piezoelectric polymeric composites subjected to electro-thermo-mechanical loadings. Since the adhesion in nanotube-based composite is universally present in the form of van der Waals (vdW) interaction, the shear stress and the axial displacement of nanotube and matrix differ in the interface zone and are not the same. This makes modeling of interface region more challenging and involved. To remedy this complexity, we propose to obtain the relative axial displacement between nanotube and polymer in the interphase zone using the Lennard–Jones potential. For this purpose, nanotube and matrix are considered as a set of concentric cylindrical shells with mechanical spring between them. The stiffness of this spring represents the strength of vdW interaction. Simulation results indicate that as the electrical load increases, the relative displacement between nanotube and polymer increases consequently, which leads to possible slippage increase. Furthermore, results demonstrate that stiffer structures show better tuning capability, which in turn, may have great potential for use in next-generation semi-active vibration control systems.