Impact Performance of Advanced High Strength Steel Thin-Walled Columns
The crashworthiness performance of spot-welded columns fabricated with advanced high strength steels is evaluated using finite element (FE) analysis. A failure criterion for the spot-welds is implemented into the FE model to predict accurately the progressive axial collapse of the columns. The behavior of two Dual Phase (DP) steels and a High Strength Low Alloy (HSLA) steel are compared by examining the mean crushing force, peak load and crushed column length for single-hat and double-hat configurations, both experimentally and numerically. Numerical results of the developed FE model correlate favorably available experimental data for different impact conditions.
Experimental and numerical studies of foam-filled sections
A comprehensive experimental and numerical studies of the crush behavior of aluminum foam-filled sections undergoing axial compressive loading is performed. Non-linear dynamic finite element analyses are carried out to simulate quasi-static test conditions. The predicted crushing force and fold formation are found to be in good agreement with the experimental results. Based on the numerical simulations, simple closed-form solution is developed to calculate the mean crushing force of the foam-filled sections. It is found that the increase of mean crushing force of a filled column has a linear dependence with the foam compressive resistance and cross-sectional area of the column. The proposed solution is within 8% of the experimental data for wide range of column geometries, materials and foam strengths.
Do Arab public opinion support policies of regional powers in MENA? View from Tunisia
ABSTRACT The Arab Uprisings and subsequent events continue to transform policies of regional and major powers toward the Middle East and North Africa. These powers have shown different approaches toward the Uprisings, ranging from support for the status quo to endorsing regime changes. Their policies have also exerted a significant impact on the course of events. Despite this growing importance and implications of policies of regional powers on the Uprisings and the Syrian conflict, we still do not know much about how the public assesses these policies and to what extent domestic cleavages shape these assessments. Using a nationally representative original survey conducted in 2014 in Tunisia, this study examines the perceptions of the policies of France, Turkey, and Saudi Arabia towards the Uprisings and the Syrian conflict. It finds that French and Turkish policies about the Uprisings have garnered substantial support among citizens, whereas most citizens negatively assess the Saudi policies. On the other hand, the majority of Tunisians negatively assess all these countries’ policies toward the Syrian conflict. Another major finding suggests that political identity reflecting secular/religious cleavages shapes how citizens view the policies of these three countries toward both issues, but its effect is higher in assessing the Uprisings.