Search results for "Shear modulus"
showing 5 items of 45 documents
STRONTIUM CONCENTRATION DEPENDENCE OF SELECTED STRUCTURAL AND MECHANICAL PROPERTIES OF POLYCRYSTALLINE Ba1−XSrXTiO3
2009
ABSTRACT Microstructure and material constants such as Young modulus E, shear modulus G, Poisson ratioν of polycrystalline ferroelectric materials Ba1-xSrxTiO3 for 0≤x≤0.4 were investigated to determine their dependence on strontium concentration. The performed investigations showed that the material is chemically homogeneous. It was found that the strontium concentration had no significant influence on the grain size. The highest value of Young's modulus is observed for Ba0.6Sr0.4TiO3 sample. The performed investigations of mechanical properties made it possible to evaluate the usability of this material for manufacturing transducers and sensors which could work under load.
Disorder Classification of the Vibrational Spectra of Modern Glasses
2021
Using the coherent-potential approximation in heterogeneous-elasticity theory with a log-normal distribution of elastic constants for the description of the Raman spectrum and the temperature dependence of the specifi?c heat, we are able to reconstruct the vibrational density of states and characteristic descriptors of the elastic heterogeneity of a wide range of glassy materials. These descriptors are the non-affi?ne contribution to the shear modulus, the mean-square fluctuation of the local elasticity, and its correlation length. They enable a physical classification scheme for disorder in modern, industrially relevant glass materials. We apply our procedure to a broad range of real-world…
Solidification behavior of the theta system 2-propanol/poly(n-butyl methacrylate)
1995
Thermoreversible gelation of the system 2-propanol/poly (n-butyl methacrylate) — as detected by D'SC or dielectric experiments — does not manifest itself in a straightforward manner in the dynamic-mechanical properties. Its occurrence can, however, be seen in many ways: i) For constant composition of the system and a reference temperature lower than Tgel, the storage modulus G′ is larger than the loss modulus G″ in the glass transition zone of the master curve and both vary in an almost parallel manner with the angular frequency ω over almost two decades (whereas this feature is normally found for other gelling systems within the rubber plateau or the flow region). ii) The entanglement mole…
Phase behavior and elastic properties of a slightly crosslinked liquid crystalline main-chain polymer
1990
A liquid crystalline main-chain polymer was slightly crosslinked by a reaction withα, ω-difunctionalized oligo-siloxanes. Crosslinking does not disturb the liquid crystalline phases, which are identified by x-ray measurements as smecticB and smecticA phases. Measurements of the elastic properties of the crosslinked sample show rubber-like elasticity, even in the liquid crystalline phases. A difference of 7 K was found between cooling and heating for the smecticA/isotropic transition from DSC and mechanical measurements.
On the limit velocity and buckling phenomena of axially moving orthotropic membranes and plates
2011
In this paper, we consider the static stability problems of axially moving orthotropic membranes and plates. The study is motivated by paper production processes, as paper has a fiber structure which can be described as orthotropic on the macroscopic level. The moving web is modeled as an axially moving orthotropic plate. The original dynamic plate problem is reduced to a two-dimensional spectral problem for static stability analysis, and solved using analytical techniques. As a result, the minimal eigenvalue and the corresponding buckling mode are found. It is observed that the buckling mode has a shape localized in the regions close to the free boundaries. The localization effect is demon…