Thermal expansion

About: Thermal expansion is a research topic. Over the lifetime, 21040 publications have been published within this topic receiving 349407 citations. The topic is also known as: heat expansion.

Prediction of springforward in continuous-fibre/polymer L-shaped parts

Abstract: Continuous-fibre-reinforced thermoset laminates that are cured hot, exhibit deformations due to cure and thermal shrinkage. When L-shaped composite components are released from the mould after cooling to ambient temperature, a decrease of the enclosed angle is observed. This is referred to as the springforward phenomenon. The main cause of springforward, the mismatch in thermal expansion along and across the fibres, cannot explain totally the springforward found in experiments. Three other possible influences on springforward were investigated: an inhomogeneous fibre/matrix distribution through the thickness, an inhomogeneous heat distribution during the cure cycle and the difference in thermal expansion between the mould and the composite component. Finite element results show that the springforward is affected significantly by the amount of cure shrinkage and by the difference in thermal expansion between the mould and the composite component.

Flexural mode of graphene on a substrate

Abstract: Out of plane vibrations are suppressed in graphene layers placed on a substrate. These vibrations, in suspended samples, are relevant for the understanding of properties such as the electrical resistivity, the thermal expansion coefficient, and others. We use a general framework to study the properties of the out of plane mode in graphene on different substrates, taking into account the dynamics of the substrate. We discuss broadening of this mode and how it hybridizes with the substrate Rayleigh mode, comparing our model with experimental observations. We use the model to estimate the substrate induced changes in the thermal expansion coefficient and in the temperature dependence of the electrical resistivity.

Structural and thermal stability of Czochralski grown GdCOB oxoborate single crystals

Abstract: Properties such as chemical and structural stability, thermal expansion and thermal conductivity are investigated, with the purpose of better characterizing the behaviour of Czochralski grown GdCOB [Ca4GdO(BO3)3], oxoborate single crystals, to be used in optical devices.

The Measurement of the Lattice Expansions and Debye Temperatures of Titanium and Silver by X-ray Methods

Abstract: A high temperature diffractometer has been used to determine the lattice spacing-temperature relations for both α- and β-titanium. For α-titanium, the mean coefficients of thermal expansion over the temperature range 0-600°C are 9.55 x 10-6 deg-1 for the a spacing, and 10.65 x 10-6 deg-1 for the c spacing; for β-titanium, the mean expansion coefficient over the temperature range 900-1070°C is about 12.0 x 10-6 deg-1. The temperature variation of the (peak) intensities of diffracted powder lines for silver is in agreement with Debye-Waller theory, after applying a correction due to Paskin, and corresponds to a Debye temperature of 197°k. Corresponding results for α-titanium indicate that the Debye temperrature is about 270° ± 30°k. Analysis of the line shapes of cold-worked titanium indicates an appreciable density of basal plane stacking fault.