Iraqi journal of mechanical and material engineering

The Mechanical properties of reinforced composite materials depend on bonding strength between reinforcements and matrix , improving the bonding strength can be achieved by surface treatment or sizing . In this investigation chemical treatment for wood excelsior carried out by using (H2O , NaCl , NaOH) solution to increase the surface roughness for excelsior surface . Group of tests was carried out to study the effect of this treatment on the mechanical (bending and compression) properties of a material composed of unsaturated polyester reinforced by (10 % wt) of treated wood excelsior . Also Calculation of the weight loss and executing of microscopic photo .
The results show :
- Increase of the bending strength of treated wood excelsior reinforced composite materials with a maximum percentage of (228 %) compared with samples reinforced with untreated excelsior . This maximum percentage was found when the excelsior are treated at room tempreature for (H2O) and (2 day) .
- Increase of the bending strength of treated wood excelsior reinforced composite materials with a maximum percentage of (40 %) compared with samples reinforced with untreated excelsior , this maximum percentage was found when the excelsior are treated at room tempreature for (10 % NaCl+90%H2O) and (8 day) .
- Increase of the bending strength of treated wood excelsior reinforced composite materials with a maximum percentage of (177 %) compared with samples reinforced with untreated excelsior , this maximum percentage was found when the excelsior are treated at room tempreature for (10 % NaOH+90%H2O) and (4 day) .
- Increase of the compression strength of treated wood excelsior reinforced composite materials with a maximum percentage of (18 %) compared with samples reinforced with untreated excelsior , this maximum percentage was found when the excelsior are treated at room tempreature for (H2O) and (4 day) .
- Increase of the compression strength of treated wood excelsior reinforced composite materials with a maximum percentage of (10 %) compared with samples reinforced with untreated excelsior , this maximum percentage was found when the excelsior are treated at room tempreature for (10 % NaCl+90%H2O) and (8 day) .
- decrease of the compression strength of treated wood excelsior reinforced composite materials with a minimum percentage of (25 %) compared with samples reinforced with untreated excelsior , this minimum percentage was found when the excelsior are treated at room tempreature for (10 % NaOH+90%H2O) and (8 day) .
- Increase of the weight loss to treated wood excelsior with (NaOH) more than weigth loss of.
treated wood excelsior with (NaCl , H2O) .

The purpose of this study is to clarify the trawler structural members subjected to random sea wave groups with large waves (hydrodynamic forces) to examine the trawler behavior under the above random loading condition to avoid future damages. By adopting the general complex modal theory, identifying the natural frequencies with corresponding mode shapes, the response of the trawler structure analysis with input from the high sea waves is carried out using a kind of direct spectrum analysis method in frequency domain. With the input of power spectral density function given, the explicit expression of the power spectral density function of the output response can be obtained. By taking Fourier inverse transforms, the integrated expressions of the correlation function and of the spectrum are obtained. The mean square values and variety of statistical values can be obtained conveniently leads to the formulation of a mathematical model of a trawler structure model. The detailed model will be used to identify the fundamental vibration mode shapes and corresponding excitation frequencies which will be used to control the safety of the trawler and the crew, to increase the trawler structure optimization, simulating the increased protection of the Trawler

The determination of critical buckling load of stiffened composite cylinder is an important factor in determining the structural stability, which was done by ANSYS program and experimental investigation. Buckling of a stiffened composite cylinder is a very complex phenomenon that involves complex interactions between the skin and the stiffeners. Depending on different configurations of the skin and stiffener, different buckling failure modes and failure loads are observed in stiffened cylinders. In this work failure modes and buckling loads of stiffened composite cylinders under uniaxial loading condition is investigated by using analytical and experimental approaches.
A three dimension finite elements models was built which takes into consideration the exact geometric configuration and the orthotropic properties of the stiffeners and the shell. Based on the finite element model the different buckling failure modes are observed.
An experimental analysis was also performed to compliment the analytical method
used to determine the buckling load of the stiffened cylinder. Good agreement in the
results are presented .

A mathematical model for calculating the temperature distribution during induction heating of a cylindrical charge has been made. In this model the temperatures of the charge at five nodes are the fundamental variables. A finite element analysis has been made for the melting process of the furnace charge for two materials which are aluminum and iron. This model was used as a reference for the performance of the estimator.
A static state estimator with a measurement redundancy of 3.33 for the induction furnace has been developed. Numerical tests show that the static state estimator is satisfactory for the use in state estimation, the weighted least squares WLS approach is an effective technique in estimation, and the criterion proposed in this work is effective for the identification process when bad data exist.

In the present work Al2O3 thin film has been deposited on glass and stainless steel 304 substrate by spray pyrolysis technique. Al2O3 was deposited with different three element(Al, Fe ,Cu) for five different percentages(1,2,3,4,5 wt %), the film was test by XRD measurements , and the topography of the films has been tested by using optical microscope, also measuring open porosity ,and Apparent density was calculated. Some of mechanical characteristics have been studied (microhardness, wear resistance). The results of XRD show that the film was crystalline with α- Al2O3 phase and grain size was 60 nm and stress ratio was 0.027%. Apparent density was 2 g/cm3 for pure Al2O3 film to 3.1g/cm3 for 5 wt% of Fe ,and open porosity was 2pore/cm2.The testes were proved that the mechanical properties results were improved after doping specially with Fe. The microhardness of the films has been improved after doping from 1346.9 Kg/mm2 for pure Al2O3 film to 1648.3 Kg/mm2 for 5 wt% of Fe on glass, and from 1413.1 Kg/mm2 to 1947.5 Kg/mm2 on stainless steel 304.Also wear resistant has been improved for the films that deposited after doping from 5.68*10-9 g/cm2 for pure Al2O3 to 3.03 *10-9 g/cm2 for 5 wt% of Fe.

The object of this paper is to evaluate the different properties (thermal, mechanical, and physical) for cellular concrete blocks. These measurements were done for two types of specimens which have the same size. The first type was used without glazing, and the second type was glazed. Many properties were measured, such as thermal shock, mechanical impact, hardness, Porosity and absorption. It has been shown through these measurements that the properties of glazed specimens were compared with that the specimens without glazing. That is mean that the glazing process was improved these different properties of cellular concrete blocks.

Experimental and numerical study has been achieved on a hypoeutectic Al - Si alloy under the effect of directional solidification in ceramic mold chilled with copper. From the coupling between experimental (microstructure evaluation) and numerical (solidification simulation) study, a model is obtained. This model can be used to predict the microstructural features of a hypoeutectic Al – Si alloys.

The main goal of combination the power plant is to achieved high efficiency in addition to reduced the production cost of the unit power produced from the plant.
This work included the cost calculation of power unit which produced from a combined power plant and the comparison this cost with that power produced from gas turbine power plant, the results shows that the price of unit power which produced from combined plant is less when the annual operation hours is more than 600 hr. This work shows also the effect of different parameter such as thermal efficiency, fuel price, and the operation years on the power unit price.

The impact strength of epoxy resin based on diglycidyl ether of bis phenol-A- with citraconiciated polybutadiene were investigated. The polybutadiene citraconiciated by reaction with citraconic anhydride and benzoyl peroxide as initiator. The percent citraconiciation was 10%.
In the present work citraconiciated polybutadiene was used as impact modifier for epoxy resin. The percentage of the blend between citraconiciated polybutadiene and epoxy resin was (5, 7.5, 12.5, and 20%) while the amine hardener of the epoxy resin was added at a ratio of 1 part amine to 3 part epoxy.

The aim of this research to use extracted natural material from waste product of Okra as blowing material by simple method for production sponge rubber. The sample of rubber was prepared with adding different percent from extracted material of waste product of Okra (0-25)% to study the effect of this material on properties of natural rubber. When we added different percent from blowing material that extracted from plant of Okra , we get productions of cells inside the sample due to degrade blowing material, release gases and get sponge rubber causes decrease specific gravity ( from 0.997 to 0.982) , tensile strength (from 13.295 to 7.881)MPa and modulus of elasticity (from 2.745 to 1.512)MPa. This mean is extracted material of waste product of Okra is suitable to use as blowing material to get sponge rubber and this work exists with a good replacement for synthetics blowing materials avoiding their toxicity and their highly cost.

the international standard specification of Dunlob Company. Reversed tension fatigue tests were performed under room temperature with stress ratio R=-1. The five types of rubber are Natural rubber [RSS,Ribbet smoke sheets] , True of tire , side wall of tire for using NR(Natural rubber , Trade of tire from standard specification of Dunlob company , and side wall of tire from standard specification of Dunlob company . It was found that , the longer fatique life is the trade rubber of tire from standard specification of dunlob company the lowest life is the Natural rubber [RSS] . The mixing between NR and BR caused reduction in fatigue life for natural rubber. Finally relationships were expressed as empirical equations.

In this paper the effect of connection geometric parameters on moment and stress distribution is reported. A comprehensive parametric analysis of steel beam-to-column connection using T-Stiffener is conducted to determine the connection behavior and stress distributions. A general-purpose finite element software, ANSYS is used to model the connection plate components with shell elements type 43. Whereas welds are modeled with linkage elements to reflect weld stiffness. The finite element mesh configurations are selected on the basis of h-refinement procedure. Geometric and material nonlinearities are incorporated in the analysis by adopting the modified Newton-Raphson technique and nonlinear stress-strain curve respectively. It is found that parameters describing the thickness of T-Stiffener web and flange plates and the ratio of beam flange width to T-Stiffener flange width have a significant effect on the connection behavior and stress distribution. Unlike conventional design assumptions, the applied moment is found to be almost equally distributed among the T-stiffener web and flange plates. Stress analysis shows that the moment capacity of a connection designed by the conventional method is limited to 43% of the beam allowable moment.

This research aims to induce the influence of nonlinear behavior material at mathematical structure by computer program for reducing the contact problem and stress state for the critical rounding profile of artificial joint. This subject computer must be modified to analysis the mechanism movement of the joint by taking different angle of rotation in the contact zone and at the edges of the joints.
For the contact problem with in nonlinear material, analytical solutions are obtained for both surface pressure and interior stress field. Cases of normal and frictional contact in both sliding and partial slip conditions are all treated.
The effect of the modification of the horizontal configuration on the stress distribution in rounded shapes of the joints have been analyzed experimentally using photo elastic pattern in different angles. The theoretical results have good agreement when compared with the experimental one.

A numerical method for the calculation of the three-dimensional wake rollup behind symmetric wings with ground effect and its aerodynamic characteristics for steady low subsonic flow have been developed. A non-planar quadrilateral vortex-ring method with vortex wake relaxation iterative scheme for lifting surfaces is obtained. A computer program was build to treat wings with breaks, span wise trailing edge flaps, local dihedral angle, camber, twist and ground effect. Forces and moments are obtained from vector product of local velocity and vortex strength multiplied by density. The program has been validated for a number of configurations for which experimental data is available. Good agreement has been obtained for these configurations. Also many results obtained for different cases of wing with different shapes parameters.