in this paper a discrete big bang-big crunch algorithm is applied to optimal design of reinforced concrete planar frames under the gravity and lateral loads. optimization is based on aci 318-08 code. columns are assumed to resist axial loads and bending moments, while beams resist only bending moments. second-order effects are also considered for the compression members, and columns are checked...

PURPOSE This study evaluated the influence of abutment materials on the stability of the implant-abutment joint in internal conical connection type implant systems. MATERIALS AND METHODS Internal conical connection type implants, cement-retained abutments, and tungsten carbide-coated abutment screws were used. The abutments were fabricated with commercially pure grade 3 titanium (group T3), c...

The aim of this study is to determine some physical and mechanical properties of Paulownia tomentosa wood grown in Turkey. The samples trees harvested from Kargi in Corum. Physical properties including air-dry density oven-dry density basic density swelling, shrinkage and oven-dry and air-dry thermal conductivity coefficients; mechanical properties including bending strength, modulus of elastic...

Modulus of elasticity of flapper valve material is an important parameter for compressor design since it can affect efficiency and life time of the compressor. Modulus of elasticity is usually considered as a material constant. Actually, it can vary with material orientations and conditions and even environments such as temperature will also affect this value. Therefore, the parameters that can...

OBJECTIVE To evaluate the mechanical properties of the Polyaxial Advanced Locking System (PAX) in screw push-out and four-point bending. MATERIALS AND METHODS Screw push-out: PAX locking screws were applied to first generation PAX plates at three different insertion angles with two different insertion torques. A load was applied parallel to the screw axis, and screw push-out force was measure...

In this paper, the effect of Polypropylene Fibers added to concrete on strength and thermal resistance of high strength concrete has been investigated. Therefore, five tests have been carried out to reach this goal which it includes; effect of weight percent of polypropylene fibers on mechanical properties of concrete, effect of fiber’s length on the strength of high strength concrete, effect o...

In this study, Al/Gr composites with 5,10,15,20 weight percent of graphite were produced by in-situ powder metallurgy method. The produced powder mixtures were consolidated and sintered at optimum conditions. The resultant composites were solution treated at 495?C and aged at 170?C. The influence of graphite content on the bending strength of composites was studied. The distribution of graphite...

Sandwich structures with thin, strong skin layers on both sides of a thick, compliant and light core combine low weight, high bending stiffness, high strength and high buckling resistance. These structures find use in many applications such as aircraft, marine applications and wind turbine blades. When used for wind turbine blades the sandwich structures are mainly made from FRP laminate skins ...