Carbon fibre reinforced polymers are widely used to strengthen steel structural elements. These structural elements are normally subjected to static, dynamic and fatigue loadings during their life-time. A number of studies have focused on the characteristics of CFRP sheets bonded to steel members under static, dynamic and fatigue loadings. However, there is a gap in understanding the bonding behaviour between CFRP laminates and steel members under impact loading. This paper shows the effect of different load rates from quasi-static to 300 × 103 mm/min on this bond. Two types of CFRP laminate, CFK 150/2000 and CFK 200/2000, were used to strengthen steel joints using Araldite 420 epoxy. The results show a significant bond strength enhancemen
... Show MoreThis work presents experimental research using draped prestressed steel strands to improve the load-carrying capacity of prestressed concrete non-prismatic beams with multiple openings of various designs. The short-term deflection of non-prismatic prestressed concrete beams (NPCBs) flexural members under static loading were used to evaluate this improvement. Six simply supported (NPCBs) beams, five beams with openings, and one solid specimen used as a reference beam were all tested as part of the experiment. All of the beams were subjected to a monotonic midpoint load test. The configuration of the opening (quadrilateral or circular), as well as the depth of the chords, were the varia
This work presents experimental research using draped prestressed steel strands to improve the load-carrying capacity of prestressed concrete non-prismatic beams with multiple openings of various designs. The short-term deflection of non-prismatic prestressed concrete beams (NPCBs) flexural members under static loading were used to evaluate this improvement. Six simply supported (NPCBs) beams, five beams with openings, and one solid specimen used as a reference beam were all tested as part of the experiment. All of the beams were subjected to a monotonic midpoint load test. The configuration of the opening (quadrilateral or circular), as well as the depth of the chords, were the varia
The use of composite materials has vastly increased in recent years. Great interest is therefore developed in the damage detection of composites using non- destructive test methods. Several approaches have been applied to obtain information about the existence and location of the faults. This paper used the vibration response of a composite plate to detect and localize delamination defect based on the modal analysis. Experiments are conducted to validate the developed model. A two-dimensional finite element model for multi-layered composites with internal delamination is established. FEM program are built for plates under different boundary conditions. Natural frequencies and modal displacements of the intact and damaged
... Show MoreThe impact of a simple trailing-edge plain flap on the aerodynamics of the SD7037 airfoil have been studied in this paper using computational fluid dynamics at Reynolds number of 3×105 across various low angles of attack and flap deflection angles. The computational model was evaluated by using Star CCM+ software with κ--ω SST turbulence and gamma transition model to solve Navier-Stokes equations. The accuracy of the computational model has been confirmed through comparison with experimental data, showing a high level of agreement at low angles of attack. The findings revealed that specific combinations of angles of attack and flap deflection angles could increase the lift-to-drag ratio by over 70% compared to baseline conditions, benefi
... Show MoreI mpact strength for Epoxy/Polyurethane, Blends and their composites with two
layers of Glass fibers (0-90) are calculated.
The impact strength of the blends and composites decrease with increasing weight
by weisht percentage of polyurethane . This result is attributed to the high elasticity
of PU , and to the immiscibility between the polymer blends as well as the fiber
delaminates
The rehabilitation of deteriorated pavements using Asphalt Concrete (AC) overlays consistently confronts the reflection cracking challenge, where inherent cracks and joints from an existing pavement layer are mirrored in the new overlay. To address this issue, the current study evaluates the effectiveness of Engineered Cementitious Composite (ECC) and geotextile fabric as mitigation strategies. ECC, characterized by its tensile ductility, fracture resistance, and high deformation capacity, was examined in interlayer thicknesses of 7, 12, and 17 mm. Additionally, the impact of geotextile fabric positioning at the base and at 1/3 depth of the AC specimen was explored. Utilizing the Overlay Testing Machine (OTM) for evaluations, the research d
... Show MoreThe most important environmental constraints at the present time
is the accumulation of glass waste (transparent glass bottles). A lot of
experiments and research have been made on waste and recycling
glass to get use it as much as possible. This research using recycling
of locally waste colorless glass to turn them into raw materials as
alternative of certain percentages of cement to save the environment
from glass waste and reduce some of the disadvantages of cement
with conserving the mechanical and physical properties of concrete
made. A set of required samples were prepared for mechanical test
with different weight percentage of waste glass (2%, 4%, 5%, 6%,
8%, 10%, 15%, 20% and 25%). American standard
PMMA (Poly methyl methacrylate) is considered one of the most commonly used materials in denture base fabrication due to its ideal properties. Although, a major problem with this resin is the frequent fractures due to heavy chewing forces which lead to early crack and fracture in clinical use. The addition of nanoparticles as filler performed in this study to enhance its selected mechanical properties. The Nano-additive effect investigated in normal circumstances and under a different temperature during water exposure. First, tests applied on the prepared samples at room temperature and then after exposure to water bath at (20, 40, 60) C° respectively. SEM, PSD, EDX were utilized for samples evaluation in this study. Flexural
... Show MoreABSTRACT
This research included the preparation and characterization of new demulsifies from natural and synthetic polymers of chitosan and polyvinyl alcohol that are environmentally friendly and at the same time have high efficacy comparable to emulsifiers. imported foreign. The prepared compounds were examined using infrared spectroscopy and nuclear magnetic resonance spectroscopy, and all the spectral signals of the polymers were in good agreement with the chemical composition of the polymers. And the melting and decomposition that occur on polymers at high temperatures. The effect of the length and type of side chain in the compositions of polymers on the process of water separation of oil emulsions w
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