Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Thermal analysis


Optical and Thermal Characterizations of PMMA Composites

Raghad S. Al-Khafaji; Kareem A. Jasim; Adil M. Ibraheim

Engineering and Technology Journal, 2019, Volume 37, Issue 2B, Pages 61-66
DOI: 10.30684/etj.37.2B.5

Thick composite films were prepared employing hand – layup method . A definite quantity of PMMA ( 98%wt ) , fixed content ( 2% wt ) of rutile titanium dioxide TiO2 , gamma alumina ( ᵞ- Al2O3 ) and Zirconia powder ( ZrO2 ) , were added to polymer solution gradually and separately. Optical constants were obtained of the prepared samples using spectrometer (UV- VIS). The prepared composite samples were thermally characterized by differential scanning calorimeter ( DSC ). We notice increasing value of glass temperature and differential heat capacity ( ∆Cp ) for composites compared with pure PMMA .

Combined Effect ofWheel and Thermal Load Conditions on Stress Distribution in Flexible Pavement

Zainab Ahmed Alkaiss; Suham E. Saleh Al-maliky

Engineering and Technology Journal, 2009, Volume 27, Issue 12, Pages 2257-2267

The aim of this research is to study the behavior of flexible pavement under
wheel and thermal loading conditions using the finite element program ANSYS V
(5.4). The stress states distribution within the asphalt concrete pavement that
influence the direction of crack propagation have been investigated. The obtained
results from ANSYS finite element program show that a maximum stress intensity
factor value obtained at surface and then decrease with depth about (0.75 of
asphalt layer thickness) due to reduction in temperature in asphalt layer, which
indicates that crack will initiate at surface and extend throughout asphalt layer.
The horizontal stress for both top and bottom layers increase with the variation of
thermal coefficient expansion factor. High values of stresses at top surface of
asphalt layer due to high contact stress were induced under wheel and thermal
load conditions. As a result the highway pavement exhibited propagation of
surface –initiated cracks. Field observation of cores extracted from asphalt
concrete pavement confirmed the obtained results.