Journal of Materials and Engineering Structures

Number 4, 2017

171-179
Packing Density Approach for Sustainable Development of Concrete

Authors: Sudarshan D. Kore, A. K. Vyas

Abstract

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Number of views: 1531

This paper deals with the details of optimized mix design for normal strength concrete using particle packing density method. Also the concrete mixes were designed as per BIS: 10262-2009. Different water-cement ratios were used and kept same in both design methods. An attempt has been made to obtain sustainable and cost effective concrete product by use of particle packing density method. The parameters such as workability, compressive strength, cost analysis and carbon di oxide emission were discussed. The results of the study showed that, the compressive strength of the concrete produced by packing density method are closer to that of design compressive strength of BIS code method. By adopting the packing density method for design of concrete mixes, resulted in 11% cost saving with 12% reduction in carbon di oxide emission.

181-192
Numerical simulation of Wind induced mean interference between two tall buildings

Authors: Santosh Gurjar, Jignesh. A. Amin

Abstract

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Number of views: 799

The assessment of wind loads on structure is generally carried out using existing codes/standards. The specifications of these codes are based on wind tunnel experiment performed on an isolated building. However, the buildings seldom exist in isolated condition. Neighbouring building may either increase or decrease the wind loads on principal building, this effect is known as interference effect. In this paper interference effect between two buildings is studied through numerical simulation using ANSYS CFX. Total drag force and interference factors for the principal building is calculated in the presence of interfering building having height ratio of 0.5, 0.75,1, 1.25, and 1.5. The results show that the upstream interfering buildings cause certain shielding effect by decreasing the mean wind load on the downstream principal building. However an amplification effect is also observed for certain location of the interfering building on upstream side. For buildings of the same cross-section, the interference factor (IF) decreases with the increase of the height of interfering building, indicating increase in the shielding effects. However the shielding effect on principal building is found to be significant when the heights of interfering buildings range from 0.75 to 1.5 of the height of the principal building. The along-wind force of the downstream principal building reduced to zero when the upstream interference building of height ratio more than one was two to three times the building breadth away from the principal building.

193-209
The Computer Algorithm for Machine Equations of Classical Distribution

Authors: Florian Ion T. Petrescu, Relly Victoria Petrescu, MirMilad Mirsayar

Abstract

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Number of views: 480

This paper presents an algorithm for setting the dynamic parameters of the classical distribution mechanism of the internal combustion engines. One presents the dynamic, original, machine motion equations. The equation of motion of the machine that generates the angular speed of the camshaft (which varies with position and rotation speed) is obtained by conservation kinetic energy of the machine. An additional variation of angular speed is added by multiplying by the coefficient dynamic D (generated by the forces out of mechanism and or by the forces generated by the elasticity of the system). Kinetic energy conservation shows angular speed variation (from the camshaft) with inertial masses, while the dynamic coefficient introduces the variation of w with forces acting in the mechanism. Deriving the first equation of motion of the machine we obtain the second equation of motion dynamic. From the second equation of motion of the machine, we determine the angular acceleration of the camshaft. It shows the distribution of the forces on the camshaft mechanism to the internal combustion heat engines. Dynamic, the velocities can be distributed in the same way as forces. Practically, in the dynamic regimes, the velocities have the same timing as the forces. Calculations should be made for an engine with a single cylinder.

211-224
RETRACTED : Elastic-plastic analysis of reinforced composite materials

Authors: Mohamed Rida Seba, Said Kebdani, Ahmed Sahli, Sara Sahli

Abstract

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Number of views: 659

This article has been retracted at the request of the Editors-in-Chief, according to the Publication Ethics Policy and Publication Malpractice Statement. Please see : http://revue.ummto.dz/index.php/JMES/about/editorialPolicies#custom-2 This note is published, 25 June 2020

225-233
Effect of Patch Shape on the Repair Efficiency of a Cracked Aluminum Panel

Authors: ElHadj Besseghier, Abdelkader Djebli, Mostefa Bendouba, Abdelkrim Aid

Abstract

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Number of views: 647

A 3-D finite element analysis was conducted on a thin aluminum plate with a 45 ° inclined central crack. A modeling of the bonding repair with composite patch of different shapes was carried out. In addition to the patch shapes studied in the literature, a new butterfly shape was proposed. The latter is defined by a length H, a width B and a neck C in the middle. The main objective is to analyze the effect of patch geometry on the rate of decrease of stress intensity factors. This rate is characterized by a coefficient R which combines between the mode I and the mode II of the rupture (KI and KII). Thus, an optimization of the patch shape is made with respect to the effectiveness in decreasing the stress intensity factor. The comparison between the results obtained with the different patch shapes has shown that the butterfly-shaped patch is more effective for relatively small surfaces. On the other hand, the extended octagon shape has been shown to be more effective for higher patch surfaces.

235-244
Green Function of Curved Rail-Beam

Authors: Mostefa Lecheheb, Rachid Lassoued

Abstract

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Number of views: 574

In this article, we study the dynamic behavior of the rail under inclined loads. The rail is modeled as a curved beam under lateral loads. When a train enters a curve, two sources lead to these lateral forces that have rarely been studied by previous researchers: the forces of action of the train result from the forces of the drawbar (due to centrifugal forces) and forces that develop due to the dynamic interaction of the vehicle and the rail. The rail is modeled as an infinite beam according to the Euler-Bernoulli theory. The use of a curved elementary section, allows to establish the solicitations that act the beam, and to write the differential equation of the system. The use of the residue theorem allows determining the Green function associated with the differential equation governing the vibration behavior of the rail system of the free beam.

245-257
Influence of ripening on the evolution of mechanical and structural properties of the AlSi12Cu1Mg alloy

Authors: Ahmed HAKEM

Abstract

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Number of views: 586

This study is firstly to determine a compromise between strength and ductility of parts made of AlSi12Cu1Mg designated by EN AC-47100, on the other hand, it aims to evaluate the influence of curing time on behavior and damage in tension and impact, Brinell hardness, microhardness and microstructure considering the states: cast, tempered, and matured. The addition of 12% silicon (gives excellent casting properties), 1% copper (facilitates machining), and magnesium up to 1% to the aluminum are the main vectors and agents of improvement of the mechanical characteristics in addition to the specific heat treatments which reveal precipitates of different kinds (Al2Cu, Mg2Si, Si, Cu, Mg) which interfere with the displacement of the dislocations.

259-267
Prediction of average annual surface temperature for both flexible and rigid pavements

Authors: Karthikeyan Loganathan, Mena I Souliman

Abstract

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Number of views: 585

The surface temperature of pavements is a critical attribute during pavement design. Surface temperature must be measured at locations of interest based on time-consuming field tests. The key idea of this study is to develop a temperature profile model to predict the surface temperature of flexible and rigid pavements based on weather parameters. Determination of surface temperature with traditional techniques and sensors are replaced by a newly developed method. The method includes the development of a regression model to predict the average annual surface temperature based on weather parameters such as ambient air temperature, relative humidity, wind speed, and precipitation. Detailed information about temperature and other parameters are extracted from the Federal Highway Administration's (FHWA) Long Term Pavement Performance (LTPP) online database. The study was conducted on 61 pavement sections in the state of Alabama for a 10-year period. The developed model would predict the average annual surface temperature based on the known weather parameters. The predicted surface temperature model for asphalt pavements was very reliable and can be utilized while designing a pavement. The study was also conducted on seven rigid pavement sections in Alabama to predict their surface temperature, in which a successful model was developed. The outcome of this study would help the transportation agencies by saving time and effort invested in expensive field tests to measure the surface temperature of pavements.