The behaviour of high-strength fiber reinforced concrete columns was observed with a testing program of 7 columns, loaded eccentrically. The theory was analyzed by modifying the stress block diagram of concrete. The experimental results show that using high-strength fiber reinforced concrete with fiber volume fraction of 1.0%, increased the column ultimate capacity up to 40% in addition to increasing its ductility and toughness, significantly. The proposed theoretical analysis gave a good estimation of experimental results.
In most cases, the concrete wall panels are subjected to axial eccentric distributed loading; due to this type of loading, concrete wall panels behave and fail somehow. There are many parameters that affect the structural behavior of the concrete wall panels. This study presents experimental investigation the structural behavior of concrete wall panels subjected to axial eccentric distributed loading; also evaluates the effect of the parameters, slenderness ratio (H/t), aspect ratio (H/L) and concrete strength on the behavior of concrete wall panels. The experimental program includes testing fifteen concrete wall panels hinged at top and bottom with free sides, by applying the load axially with eccentricity equal to (t/6); these panels are divided into five groups, each group consists of three panels with slenderness ratio (H/t) equals to (20 , 25 , 30) for each panel, three groups of normal concrete strength with aspect ratio (H/L) equal to (1.0 , 1.5 . 2.0) for each group and the other two groups are of high strength concrete with aspect ratio (H/L) equal to 2.0 for both two groups. The deflections of concrete wall panels depend on the slenderness ratio (H/t), aspect ratio (H/L) and concrete strength. The failure mode of the concrete wall panels is greatly affected by the aspect ratio (H/L); the panels with low aspect ratio tend to fail by crushing, while panels with high aspect ratio tends to fail by buckling.
This paper deals with a numerical investigation of natural convection of heat transfer in a horizontal eccentric annulus between a square outer enclosure and a heated circular inner cylinder. The governing equations are expressed by the term of the stream function-vorticity with dimensionless temperature. The body fitted coordinate system (BFC) was used to stretch over the physical domain of the presented problem. The Poission's equation of stream function is solved by successive over relaxation (SOR) method, while time marching technique was the best choice to solve both vorticity and energy equation.The results are presented for the streamlines and isotherms as well as the average Nusselt number at different eccentricities and angular positions. Comparison with previous theoretical results shows good agreement.
The Cooper-Harper rating of aircraft handling qualities has been adopted as a standard for measuring the performance of aircraft. In the present work, the tail plane design for satisfying longitudinal handling qualities has been investigated with different tail design for two flight conditions based on the Shomber and Gertsen method. Tail plane design is considered as the tail/wing area ratio. Parameters most affecting on the aircraft stability derivative is the tail/wing area ratio. The longitudinal handling qualities criteria were introduced in the mathematical contributions of stability derivative. This design technique has been applied to the Paris Jet; MS 760 Morane-Sualnier aircraft. The results show that when the tail/wing area ratio increases the aircraft stability derivative increases, the damping ratio and the natural frequency increases and the aircraft stability is improved. Three regions of flight conditions had been presented which are satisfactory, acceptable and unacceptable. The optimum tail/wing area ratio satisfying the longitudinal handling qualities and stability is (0.025KeywordsLongitudinal Handling---Stability---Tail Design