Topic

# Thermomechanical analysis

About: Thermomechanical analysis is a research topic. Over the lifetime, 2144 publications have been published within this topic receiving 43054 citations.

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14 Dec 1997

TL;DR: An Introduction to Dynamic Mechanical Analysis as discussed by the authors is a good starting point for a discussion of the application of dynamic testing in real world problems, as well as guidelines for DMA applications to real problems.

Abstract: An Introduction to Dynamic Mechanical Analysis. Basic Rheological Concepts: Stress, Strain, and Flow. Rheology Basic: Creep-Recovery and Stress Relaxation. Thermomechanical Analysis. Dynamic Testing. Time-Temperature Scans Part I: Transitions in Polymers. Time and Temperature Studies: Part II Thermosets. Frequency Scans. DMA Applications to Real Problems: Guidelines.

1,435 citations

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01 Jan 1986

TL;DR: In this paper, the authors consider the thermal properties of harmonic lattice vibrations in real crystals and atomic vibrations in defect lattices, as well as the properties of anisotropic and polycrystalline materials.

Abstract: Preface. Chapter 1. Bonding characteristics. 2. Crystal defects. 3. Elasticity. Basic relations. 4. What values do the elastic constants take? 5. Sound waves. 6. The phonon spectrum. 7. Thermal properties of harmonic lattice vibrations. 8. Phonons in real crystals: anharmonic effects. 9. Atomic vibrations in defect lattices. 10. Thermodynamic properties of conduction electrons. 11. Thermal properties of few-level systems and spin waves. 12. Melting and liquids. 13. Equation of state and thermal expansion: macroscopic relations. 14. Thermal expansion: microscopic aspects. 15. Electrical conductivity of metals and alloys. 16. Thermal conductivity. 17. Transport, elastic and thermal expansion parameters of composite materials. 18. Anisotropic and polycrystalline materials. 19. Estimations and correlations. Appendices. Author index. Subject index. Materials index.

1,114 citations

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TL;DR: In the temperature range studied the model amorphous solids were in a transition zone between regions of very high molecular mobility above Tg and very low molecular mobility much further below Tg, which should be expected to experience significant molecular mobility at temperatures up to fifty degrees below their glass transition temperature.

Abstract: Purpose. To measure the molecular mobility of amorphous pharmaceutical solids below their glass transition temperatures (Tg), using indomethacin, poly (vinyl pyrrolidone) (PVP) and sucrose as model compounds.
Methods. Differential scanning calorimetry (DSC) was used to measure enthalpic relaxation of the amorphous samples after storage at temperatures 16-47 K below Tg for various time periods. The measured enthalpy changes were used to calculate molecular relaxation time parameters. Analogous changes in specimen dimensions were measured for PVP films using thermomechanical analysis.
Results. For all the model materials it was necessary to cool to at least 50 K below the experimental Tg before the molecular motions detected by DSC could be considered to be negligible over the lifetime of a typical pharmaceutical product. In each case the temperature dependence of the molecular motions below Tg was less than that typically reported above Tg and was rapidly changing.
Conclusions. In the temperature range studied the model amorphous solids were in a transition zone between regions of very high molecular mobility above Tg and very low molecular mobility much further below Tg. In general glassy pharmaceutical solids should be expected to experience significant molecular mobility at temperatures up to fifty degrees below their glass transition temperature.

926 citations

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TL;DR: The thermal properties of the 14 nonmagnetic cubic metals through the 4d transition series are derived from first-principles electronic-structure calculations coupled with a Debye treatment of the vibrating lattice.

Abstract: The thermal properties of the 14 nonmagnetic cubic metals through the 4d transition series are derived from first-principles electronic-structure calculations coupled with a Debye treatment of the vibrating lattice. Debye temperatures and Gr\"uneisen constants are derived from an analysis of the compressional characteristics of rigid-lattice binding curves and are used to define the contribution of the lattice vibrations to the free energy. A minimization of the resulting free energy with respect to volume yields temperature-dependent lattice separations and coefficients of thermal expansion. Theoretical values of cohesive energies, equilibrium lattice separations, bulk moduli, Debye temperatures, Gr\"uneisen constants, and coefficients of thermal expansion are derived directly from computed electronic-structure results. Good agreement with experiment is found for all computed quantities.

667 citations

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TL;DR: In this article, the authors present a comprehensive source of reported literature involving dynamic mechanical properties of natural fiber reinforced polymer composites, hybrid and nano composites and its applications and provide a perfect data to explore its industrial application primarily as cheaper construction and building materials for doing further research in this topic.

628 citations