We studied the geophysical, physical, and geomechanical parameters of the Podlesí granites in the western part of the Krušné hory Mts., near the village of Potůčky. The granites represent a fractionated intrusion within the Nejdecký Massif. In total, the studied borehole is about 300 m deep. The samples were collected at depths of between 35 and 105 metres. Seismic P-wave and S-wave velocities were measured using ultrasonic scanning. The samples were water-saturated, unsaturated, and dried. The ultrasonic scanning system consisted of four piezoelectric sensors and a digital oscilloscope recorder. The wave frequency was 1 MHz. P-wave velocities range from 4400 m.s-1 to 6500 m.s-1 while S-wave velocities range from 2800 m.s-1 to 3800 m.s-1. These data were used to calculate dynamic Young’s modulus, dynamic shear modulus, and Poisson’s ratio. The deformational characteristics of the rock were specified from experimental loading of the sample with uniaxial strain. The shear and longitudinal deformation of each sample was measured using a resistive strain gauge fixed directly on the sample. Intermittent loading of the samples proceeded using a uniform gradient of axial stress of 1 MPa.s-1. The samples were subjected to five separate loads. During the tests, following parameters were recorded: stress, longitudinal deformation, and shear deformation. These data were used to calculate static Young’s and shear modulus, and Poisson’s ratio., Lucie Nováková, Karel Sosna, Milan Brož, Jan Najser and Petr Novák., and Obsahuje bibliografii
Elastic constants play a crucial role in mechanical properties of material. Quick and effective measurement method that determines this value is benefit for branches interesting in material science and development. One of these branches is deposition of thin films, where it is possible to produce material with various structures and properties. There is a perspective Laser Acoustic Wave (LAW) method described in the article. This method is based on a measurement of velocity and dispersion of surface acoustic waves (SAW). Using the LAW method thin films of amorphous silicon (a-Si) and silicon carbide (a-SiC) have been measured. Some of the obtained results are presented in the text. In the conclusions main advantages and disadvantages are pointed out and some solutions of the disadvantages are suggested. and Hodnoty elastických konstant (Youngův, resp. elastický modul a Poissonovo číslo) jsou klíčové z hlediska hodnocení mechanických vlastností materiálu. Rychlá a efektivní metodika měření těchto veličin je přínosem ve vývoji materiálů, např. tenkých funkčních vrstev a povlaků, kde je možno změnami parametrů procesu depozice připravit vrstvy o různých materiálových vlastnostech. V článku je popsána velmi perspektivní metoda měření LAW (z angl. Laser Acoustic Waves) určující elastické vlastnosti tenkých vrstev. Metoda je založena na měření rychlosti a disperze povrchového akustického vlnění (SAW - z angl. Surface Acoustic Waves). Jsou prezentovány některé výsledky měření vrstev amorfního křemíku a karbidu křemíku (a-Si a a-SiC) dosažené touto metodou. V závěru jsou uvedeny hlavní výhody a nevýhody LAW a nastíněno jejich možné řešení.