A 70 mm-open-ended coaxial line probe was developed to perform measurements of the dielectric properties of large concrete samples. The complex permittivity was measured in the frequency range 50 MHz – 1.5 GHz during the hardening process of the concrete. As expected, strong dependence of water content was observed.

A type of nonlinearity in vibrational engineering systems emerges when the restoring force is a nonlinear function of displacement. The derivative of this function is known as stiffness. If the stiffness increases by increasing the value of displacement from the equilibrium position, then the system is known as hardening type oscillator and if the stiffness decreases by increasing the value of ...

The goal of this contribution is the development of a plane stress orthotropic plasticity material model for clear spruce wood. Such a model has to consider an initially linear elastic domain as well as hardening and softening behaviour at higher states of stress and strain, respectively. Combining the advantage of a smooth single-surface plasticity model with the identification of distinct har...

Hysteretic and nonlinear dielectric behaviour in ferroelectric ceramics has been of interest since 1950s, when these materials found application in various electronic devices. Presently, these phenomena concern with important areas of science, technology and engineering. In particular, nonlinearity and hysteresis are the key factors in performance, precision and accuracy of modern devices. Many...

A general methodology is proposed for representing and propagating the effects of uncertainties in complex nonlinear systems through the use of a model-free representation, that allows the estimation through analytical procedures of the uncertain system’s response bounds when it is excited by a different dynamic load than the one used to identify it. A nonparametric identification approach base...

Indentation is a new method for estimating residual stress. The plastic behavior of the materials under study can affect indentation parameters and, thus, influences the results of residual stress measurement. In this paper, the effect of yield stress and work-hardening exponent on the accuracy of residual stress measurements in steels and aluminums was studied. Results showed that, for m...

Miniaturization of electronics to the nanoscale brings new challenges. Because of their small size and immense information and power processing capacity, large temperature gradients exist across nanoelectronics and power electronics solder joints. In this paper, a fully coupled thermomechanical-diffusion model is introduced to study the thermomigration induced strength degradation. A nonlinear ...

The evolution of plastic deformation and damage in steel frame buildings caused by seismic action is simulated based on a modified damage model. This model combines nonlinear isotropic and kinematic hardening criteria with a damage evolution law expressed in terms of plastic displacement. A nine-story steel frame is chosen as a reference structure, and a nonlinear damage analysis is performed u...

Abstract In this contribution a brief overview of the development of an orthotropic material model for the simulation of clear spruce wood under simultaneous biaxial in-plane stresses and transverse shear stresses is given. The model considers an initially linear elastic domain as well as hardening and softening behaviour at higher states of stress and strain, respectively. Combining the advant...