The problems at investigation of state of stress of thick orthotropic plate

The determination of state of stress of thick orthotropic plate is outlined here. The analytical formulations of dispersion curves for arbitrary direction of wave propagation in orthotropic plate, which we defined earlier, are used to obtain results. The false roots appearing in the numerical computation of thick plate dispersion curves from orthotropic materials are mentioned. The displacements and the stresses of the thick orthotropic plate are presented too

Analysis of the conical piezoelectric acoustic emission transducer

Analyses of the properties of conical piezoelectric acoustic emission transducer are presented here. The conical piezoelectric transducer is used to scanning normal displacement on a surface of testing constructions in NDT methods, such as acoustic emission. The simplified one-dimensional analysis based on the equivalent circuit of conical waveguide is recapitulated. FEM analysis on this transducer is presented. Both the frequency response characteristic of the transducer and his time response on pulse excitation are results of this analysis. All of computations are done for various cone angles of piezoceramic (PTZ-H5) element and various sizes of the cylindrical backing of the sensor

The simulation of a wave propagation in a bcc iron crystal with a crack

We present a large-scale molecular dynamic simulations of a wave propagation in a bcc iron based on a N-body potential model which gives a good description of an anisotropic elasticity. A crack is embedded in a bcc iron crystal having a basic cubic orientation. We consider a central pre-existing Griffith (through) crack. The crystal is loaded on its front face and the response is detected on its opposite face. The acquired results are very important for the new NDT nano scale methods

Acoustic emission source modeling

The paper deals with the acoustic emission (AE) source modeling by means of FEM system COMSOL Multiphysics. The following types of sources are used: the spatially concentrated force and the double forces (dipole). The pulse excitation is studied in both cases. As a material is used steel. The computed displacements are compared with the exact analytical solution of point sources under consideration