Iraqi journal of mechanical and material engineering

Finite element (FE) method is presented for the analysis of thin rectangular laminated composite decks plates under the biaxial action of in – plane compressive loading. The analysis uses the classical laminated plate theory (CLPT) which does not account for shear deformations. In this theory it is assumed that the laminate is in a state of plane stress, the individual lamina is linearly elastic, and there is perfect bonding between layers. The classical laminated plate theory (CLPT), which is an extension of the classical plate theory (CPT) assumes that normal to the mid – surface before deformation remains straight and normal to the mid – surface after deformation. Therefore, this theory is only adequate for buckling analysis of thin laminates. A Fortran program has been developed. New numerical results are generated for in – plane compressive biaxial buckling which serve to quantify the effect of boundary conditions on buckling loading. It is observed that, for all cases the buckling load increases with the mode number but at different rates depending on whether the plate is simply supported, clamped or clamped – simply supported. The buckling load is a minimum when the plate is simply supported and a maximum when the plate is clamped. Because of the rigidity of clamped boundary condition, the buckling load is higher than in simply supported boundary condition. It is also observed that as the mode number increases, the plate needs additional support.

An experimental and theoretical study of air forced convection heat transfer at Reynolds number (1091.5 to 1560) around a circular cylinder placed in an iron test section (0.2x0.2x0.4 m3) filled with saturated porous material glass balls of 5mm in diameter. A copper circular cylinder heater of diameter 0.015m and length 0.2m is heated electrically; it is located in different positions in X and Y direction within the test section. The forced convection heat transfer is simulated using the ANSYS program (Fluent). The results showed that the surface temperature distribution of the cylinder has the same trends for the different locations within the test section. The average Nusselt number increases with Reynolds number and heat flux. Also, the results show that the use of porous material improves heat transfer by 67.4%. The maximum percentage deviation between the experimental and theoretical results is 1.622%. Moreover, experimental correlations were introduced and comparison was performed between the present results with the previous studies and it gives a good agreement.

The fresh water reserves on the earth are finite. The brackish water can be converted to the fresh water by solar water distillery. A theoretical investigation to investigate the effect of the turning hollow-cylinder within the solar still equipped with flat plate solar water collector on the output of distillate water and its thermal efficiency. The numerical analysis was carried out by using FORTRAN 90, program. The numerical analysis is used for complex phenomena without resorting to expensive prototypes and difficult experimental measurements. The study considered several parameters which are; solar radiation intensity, ambient air temperature, ambient wind velocity, basin plate temperature, basin water temperature, glass cover temperature and hollow cylinder surfaces temperature. The cumulative of distillate water output from the modified solar still increased compared with the conventional solar still by a factor not less than 240%.

The climate change and water scarcity are the most world environmental challenges. Producing fresh water from seawater needs a lot of energy that may be supported by fossil fuel power stations. However, a solution for the challenges is water desalination system that is integrated to the renewable energy. Moreover, there is much energy conversion in these systems that reduce the overall system efficiency. This article introduces a novel Desalination Wind Turbine, and such that it is described and analyzed by nonlinear simulation. In this system, the wind energy transmitted to the water pump by a hydraulic transmission line. The RO module is used for fresh water production. The long-term performance of the system, such as annual water production is calculated and the ability of the system to Maximum Power Point Tracking and the wind turbulence and wind sudden change is analyzed, which shows the system overshoot is less than 6%.

Recently, scratch technique is widely used for characterizing the mechanical properties of a wide range of surfaces. In the engineering applications and in order to determine the relative hardness of materials, coatings and paints evaluations, and appraisal a variety of material damage countenance when subjected to asperity of the hard counterface, a scratch test was successfully used. In the current work, we have reviewed theoretical models that have been developed in the field of scratching and the scratch way that used for characterization polymeric surfaces. In order to design scratch-resistant polymers, we also discussed the various wear and scratch damage mechanisms for polymer and its composites. In addition, we discussed the influence of types and concentration of filler on the wear and scratch resistance. The aim of this work is to review the theoretical models that have been developed in the field of scratching and the scratch way that used for characterization polymeric surfaces.

In this paper a quarter-vehicle full-scale suspension test rig was designed and manufactured, the suspension is considered semi-active as the electrohydraulic (EH) damper used is fully controlled. This gives an indoor-based simulation tool which is important for vehicle testing;. This reduces the cost significantly with accurate results, especially when designing a new suspension system. The aim of the current work was to build a new quarter-vehicle test rig with expandable capabilities for diverse design objectives, also may be used for academic purposes. The control objective was achieved by using dynamic characteristics of the electrohydraulic (EH) damper to suppress the oscillation of the sprung mass due to road irregularities. The test rig was constructed using a Genesis G80 (2016) suspension system. Finally, the simulation results demonstrated that the proposed controller used be able to efficiently regulate the chassis vertical oscillation under these irregularities. The experimental results for the quarter-car model showed good results between experimental and simulated results, where the proportion of conformity about 95%.

ABSTRACT
In this project, the flow distribution for air and water, and the enhancement of the heat transfer coefficient are experimentally studied. Experimental studies have been performed to test the influence of discharge, pitch, the height of ribs at a constant heat flux on the temperature and pressure distributions. Along the channel of the test and the heat transfer coefficient, the water volume flow rate was about (5-12 L/min), the air volume flow rate was about (5.83-16.66 L/min), and heat were (80, 100,120, watt). An experimental rig was constructed within the test whole system. On the other hands, the channel has a divergent section with an angle =15o with vertical axis. The study included changing in the ribs height by using three values (12, 15, 18 mm) and changing the ribs pitch into three values (5, 8, 10 mm).The results indicated an increasing in the local heat transfer coefficient as a result of increasing the discharge. While there was an inverse influence for the temperature distribution along the test channel which drops when the discharge rise. The results also confirm that the increasing in the pitch distance leads to reduce the heat transfer coefficient. Increasing the ribs height increases the coefficient of heat transfer. However, the experiment heat transfer coefficient improves about (15.6 %) when the water volume flow rate increased from (5 to 12 L/min), and about (18.7%) when the air volume flow rate increased from (5.83 to 16.66 L/min). The best heat transfer coefficient was about (35.6 %) which can be achieved when the pitch decreased from (10 to 5mm). The increasing of the height from (12 to 18) mm improves the heat transfer coefficient about (11.2 %). The best rib dimension was 18 mm height, and 5 mm pitch, which give a maximum heat transfer coefficient (1212.02 W/m2. oC).