Guided elastic waves in the frequency range of a few hundred kHz, generated and detected by appropriate transducer arrays, are used to monitor the structural integrity of pipes by comparing their actual state with a predefined reference state. For these purposes, theoretical, numerical, and experimental results are combined to study guided wave propagation and wave interaction with relevant def...

This paper employs one-dimensional numerical ground response analysis models to investigate seismic response of shallow cohesive and non-cohesive soil deposits on vertical propagation of horizontal shear waves. Soil response is modelled by traditional equivalent-linear (EL) frequency-domain analysis using DEEPSOIL software and nonlinear (NL) time-domain analysis using OPENSEES software. The ana...

Guided waves based methods are widely used for damage detection and localization in metallic and composite structures. Success of the method application depends on many factors like sensors/actuators location, sensor electronic system design, sensor shape, frequency range of excitation waves and applied signal processing procedures. Authors developed new modified LISA and EFIT algorithms to sol...

The purpose of this research is to analyze heat waves characteristics in the warm period of the year as a climatic hazard in Iran. In this study, the daily maximum temperature is taken at 44 synoptic stations during the period 1981-2010. These temperature values were used to extract the intensity, frequency and duration of heat waves using percentile thresholds of 90, 95, and 98. The results sh...

We present a ray-tracing study of the propagation of PC 3 Alfven mode waves originating at the dayside magnetopause. This study reveals interesting features of a magnetospheric filter effect for these waves. PC 3 Alfven mode waves cannot penetrate to low Earth altitudes unless the wave frequency is below approximately 30 mHz. Configurations of the dispersion curves and the refractive index show...

Abstract Advanced research into non-destructive control of industrial pipeworks provides several acoustical methods for inspection of their structural integrity. Applying guided waves is one possible solution to detect and identify different flaws. Many studies have shown the importance of complex waves describing the interaction phenomena at the vicinity of the defects, modeled as geometrical ...

We report on the experimental study of the propagation of surface guided waves in a periodic arrangement of pillars on a semi-infinite medium. Samples composed of nickel pillars grown on a lithium niobate substrate were prepared and wide bandwidth transducers were used for the electrical generation of surface elastic waves. We identify a complete band gap for surface guided waves appearing at f...