TSSM: Three-State Switchable Memristor Model Based on Ag/TiOx Nanobelt/Ti Configuration

Memristive technologies are attractive due to their nonvolatility, high density, low power, nanoscale geometry, nonlinearity, binary/multiple memory capacity, and negative differential resistance. For memristive devices, a model corresponding with practical behavioral characteristics is highly favorable for the realization of its neuromorphic system and applications. In this paper, we propose a novel memristor model based on the Ag/TiOx nanobelt/Ti configuration, which can reflect three different states (i.e. original stage, transition stage, and resistive switching state) of the physical memristor with a satisfactory fitting precision (greater than 99.88%). Meanwhile, this work gives (1) an insight onto the electrical characteristics of the memristor model under different humidity conditions; (2) the influence of the water molecular concentration on the memristor behavior, which is of importance for the memristor fabrication and subsequent applications. For verification purposes, the proposed three-state switchable memristor is applied into the memristor-based logic implementation. The experimental results demonstrate that the constructed circuit is able to realize basic Boolean logic operations with fast response speed and high efficiency.

Fastener Scaffold Stability Analysis and Experimental Research Under Non-Uniform Distributed Load

Introduction: An experiment was carried out on the basis of material nonlinearity, geometry nonlinearity and semi rigid fasteners for the internal force distribution and transfer rules of the scaffold. Methods: This paper presents results from a set of numerical studies on the influence of the random imperfection method, the interaction of various imperfections and the most disadvantageous stability limit load. Result and Conclusion: Data from numerical studies indicate that stress at the top of the vertical bar was larger within the scope of load; and the horizontal bar and brace participated in the work of the scaffold. The internal force that came through the two types of bars enabled us to realize the redistribution in every vertical bar in order to decrease the stress from the top to the bottom of the vertical bars and involve them in the work of the scaffold. Data from numerical studies also indicates that these imperfections all interact with each other and the load distribution also influences the scaffold’s stability.

Research on the Geometry Nonlinearity of Wind Turbine Blade

It is presented that the nonlinear aeroelastic effect is considered for the dynamic response analysis of large scale horizontal wind turbine. The blade of wind turbine is built by composite laminate model using the finite element method. The unsteady aerodynamic loads are predicted with prescribed vortex wake method, which considers the aerodynamic-structural coupling effects. The aerodynamic loads are applied to the blade structure model, and the nonlinear dynamic aeroelastic equations are established. The equations are linearized and the blade modes are obtained at the static equilibrium position, thus the dynamic responses of a blade are calculated using the modal method. The results show that the geometry nonlinearity reduces the vibration amplitudes of the blade.

The Influence of Initial Guy Cable Prestress on Single-Mast Guyed Towers Mechanical Properties

A single-mast guyed tower recommended by a UHV DC transmission line was set as an example. To study initial guy cable prestresss influence on guyed towers mechanical properties, the guyed tower under wind load was analyzed with finite element method considering geometry nonlinearity. Result shows: when initial guy cable prestress is less than critical guy cable prestress, with the growth of initial guy cable prestress, nodes displacement decreases, guy cables work stress and leg members axial force stay; when initial guy cable prestress is greater than critical guy cable prestress, with the growth of initial guy cable prestress, nodes displacement stays, guy cables work stress and leg members axial force proceed a linear increase.

Buckling Analysis of Wind Power Tower Considering the Effect of Nonlinearity

Based on the 3D finite element model of the wind power tower, buckling behavior of the wind power tower in different wind directions is analyzed, and the effect considering geometry nonlinearity and considering the material and geometry nonlinearity to the buckling analysis is studied. The results show when the ratio of the radius of the tower drum and the length of the element is 18.75, the calculated precision can reach 95%. Local buckling of the wind power tower first appears, and buckling load and displacement considering the material and geometric nonlinearity reduce 52% and 58% compared with that only considering geometry nonlinearity. The linear and nonlinear buckling load of the wind power tower which is 90° sidewind are 1.8 and 1.2 times than those facing the wind direction.

Direct influence of residual stress on the bending stiffness of cantilever beams

Although the cantilever beam has been widely used as a sensor to measure various physical quantities, important issues such as how residual stress affects its bending stiffness and what are the underlying physical origins have not been fully understood. We perform both theoretical analyses and finite-element simulations to demonstrate for the first time that without changing the material tangent stiffness, residual stress within the beam can directly influence the bending stiffness of the beam. This direct influence arises from two origins: geometry nonlinearity and Poisson’s ratio effect. For a cantilever beam with adsorbed macromolecules on its surfaces, we find that longer macromolecular chains have lower normal stiffness and larger intermolecular forces, which makes the effect of the residual stress more pronounced. The excellent agreement between our theoretical predictions and finite-element calculation results validate our analysis. The present work provides an important framework for improving the sensitivity of a cantilever beam as a sensor.

Numerical Study of Large Defection of Functionally Graded Beam with Geometry Nonlinearity

The equation of large deflection of functionally graded beam subjected to arbitrary loading condition is derived. In this work assumed that the elastic modulus varies by power function in longitudinal direction. The nonlinear derived equation has not exact solution so shooting method has been proposed to solve the nonlinear equation of large deflection. Results of shooting method are validated with finite element solutions. The method will be useful toward the design of compliant mechanisms driven by smart actuators. Finally the effect of different elastic modulus functions and loading conditions are investigated and discussed.

Frequency Clustering in Cyclic Symmetric Rotors Considering Geometry Nonlinearity

Motivated by finite element results of a bladed disk model, a discrete model and numerical analysis are developed and presented in this paper with view toward understanding effect of large geometric design factors on the vibrations of a cyclic symmetric integrally bladed rotor (IBR). It is found that nonlinear eigenvalue-loci crossing for split frequency doublet modes and eigenvalue-loci veering for repeated frequency modes having the same wavenumber content can occur when large blade span distribution and blade to disk inertia ratio are considered in the discrete IBR model. Clustering of eigen-loci is found and characterized in blade span parameter study when blade’s inertia is significant large. These three findings are new to the literature and have engineering implications on structure design and vibration control of engine components in turbine and automobile applications.