Sharif Digital Repository

This paper presents the results of an experimental and analytical study on the improvements gained in the axial compressive behavior of confined concrete. Among several parameters affecting compressive ductility of confined concrete, including confinement mechanical volumetric ratio, shape and size effect, number of confinement layers, strength of plain concrete and ductility of confining material, the latter was found to play the most important role in determining the ultimate strain and post peak behavior of concrete. Axial compressive tests were performed on small-scale circular or square section concrete columns, which were retrofitted either by CFRP jacket or by two types of... 

Alumina dispersion-strengthened copper was produced by an internal oxidation process and hot powder extrusion method. The microstructure of the composite consisted of fine-grained region with an average grain size of 1.1 ± 0.1 μm, coarse-grained region with an average grain size of 5.6 ± 0.1 μm, nanometric alumina particles (γ-type) with an average diameter of 30 nm, and coarse alumina particles (350 nm) at the boundaries of the large grains. The tensile and fatigue fracture of the composite was studied in the extruded condition and after 11% cold working. The low cycle fatigue behavior was examined in strain control mode (ε = 0.5%) under fully reverse tension-compression cycle at 1 Hz up to...