Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : stress


Modeling and Simulation of Telescopic Hydraulic for Elevating Purposes

Istabraq H. Abed Al-Hady; Farag M. Mohammed; Jamal A.K. Mohammed

Engineering and Technology Journal, 2022, Volume 40, Issue 1, Pages 226-232
DOI: 10.30684/etj.v40i1.2253

The hydraulic cylinder is widely used in industry as the load lifting structures. A telescopic hydraulic cylinder is a special design of a cylinder with a series of gradually smaller diameter tubes overlapping each other. Three-stage telescopic cylinder performance analysis is performed with the help of the Finite Element Method. Also, MATLAB Simulink is used to create a complete design of the dynamic model of the telescopic cylinder. The analysis results of characteristic curves for telescopic cylinder position, velocity, and acceleration show the simulation model's accuracy and plausibility. This package will provide a basic reference for analyzing and designing the hydraulic cylinders with any number of stages. Simulation results show that a sudden change of pressure upon phase change will lead to multi-phase vibration.

Numerical Analysis of Linear Elevator Structure Using Finite Element Method

Saba A. Othman; Jamal A.-K. Mohammed; Farag M. Mohammed

Engineering and Technology Journal, 2021, Volume 39, Issue 9, Pages 1430-1436
DOI: 10.30684/etj.v39i9.2083

In this work, the structure of the linear elevator prototype had been investigated numerically using finite element method. The linear motor structure parameters analyzed using Maxwell ANSYS. The time-stepping method depending on Maxwell equations be applied for analyzing and optimizing the magnetic and force characteristics. While the elevator structure parameters were analyzed using ANSYS workbench based on the principle of virtual work. The frame considered as clamped- clamped beam, and the base of the car considered as thin plate with small deflection. The analysis done with maximum applied load of 360 N at 1.5 safety factor. The results show the distribution of the magnetic lines, the flux density values plus the leakage flux inside the slots. The maximum Von-Mises stress and the deformations of the frame and plate at maximum load are acceptable and present save design. In which the maximum deflection of the thin plate not exceed (thickness/5) at maximum design load.  

Crack Propagation in Cement Mortar Exposed to External Sulfate Attack

M.H. Abedalrazzaq

Engineering and Technology Journal, 2017, Volume 35, Issue 4, Pages 411-420
DOI: 10.30684/etj.35.4A.14

This study displays experimental investigation to find out the effect of the external sulfate attack on crack propagation in cement mortar cubes exposed to two sulfate solutions. For this purpose, five mixes of mortar are designed to cast 90 cubes (18 cubes of each mix) and two sulfate solutions (magnesium sulfate MgSO4 and sodium sulfate Na2SO4), each of 34000 p.p.m SO4-2 concentration are prepared. The cubes are evenly distributed in each of the solutions and in tap water as well. The testing technique is carried out compressive strength and Ultrasonic Pulse Velocity (UPV) tests simultaneously to specify the stress/strength ratio at which cracks propagate. The tests are carried out after 56 and 150 days of exposing to sulfate solutions. The results show that crack propagation takes place in specimens exposed to sulfate solutions at stress/strength ratios higher than those which are kept in tap water. The main conclusion, according to this study results, is that sulfate particles delay the propagation of cracks in cement mortar cubes.

Prediction of the Nominal Bending Moment Capacity for Plain and Singly Reinforced Rectangular RPC Beam Sections

Hisham M. Al-Hassani; Wasan I. Khalil; Lubna S. Danha

Engineering and Technology Journal, 2015, Volume 33, Issue 5, Pages 1113-1130

A new generation of Ultra High Performance Concrete (UHPC) named Reactive Powder Concrete (RPC) was developed in the last decades, which offers, superior strength, durability and ductility. One of the main differences between other concretes and RPC is that the latter requires mechanical models capable of taking tensile behavior into account for structural application to enable the material to be fully exploited. The complete stress-strain relationship under direct tensile test and uniaxial compressionof differentRPC mixes was experimentally investigated. Nonlinear equations are suggested to model the complete tensile and compressive stress-strain relationship for all the RPC mixes studied. In this research an analytical study is devoted to establish a simple equation for predicting the nominal bending moment capacity Mn of plain and singly reinforced rectangular RPC beam sections. The equation derived showed good agreement with all the flexural test results performed in previous researches and some other investigations on reactive powder concrete beams.

Finite Element Analysis of the Boom of Crane Loaded Statically

Bakr Noori Khudhur

Engineering and Technology Journal, 2013, Volume 31, Issue 9, Pages 1626-1639
DOI: 10.30684/etj.2013.82179

In this paper, the finite element analysis was carried out on boom of telescopic crane using ANSYS package software and the manual calculation as well as the analysis by the strength of materials procedure. The stress picture along the boom model was conducted under the maximum load carrying capacity. The stress developed at the interception of hydraulic rod with the first tube is higher than that developed along the rest of the boom. Moreover, the maximum deflection occurs at the boom head sheave.
In order to investigate the accuracy of the results, a comparison between the two approaches and the exact obtained by the strength of materials procedure is carried out.
Although the high capabilities of ANSYS software, the results are somewhat less accurate than that obtained by the manual calculations. Besides that, the results obtained by the finite element manual calculations are wholly similar to that of strength of materials procedure. Model taken for this paper is TADANO TR-350 XL 35-ton capacity.

Mechanical and Tribological Behavior of Glass- Polyester Composite System under Graphite Filler Content

Farag M. Mohammed; Drai A. Smait

Engineering and Technology Journal, 2012, Volume 30, Issue 4, Pages 672-683
DOI: 10.30684/etj.30.4.13

Experimental investigations had been done in this work to demonstrate the effect of
graphite filler contents on the mechanical and tribological behavior of (30% volume
fraction) glass-polyester composite system. The stress-strain relations, modulus of
elasticity, yield stress, ultimate tensile strength and ultimate compression strength were
studied according to ASTM-D 638-87and ASTM-D 695 to present the composite
mechanical behavior. The wear rate and wear resistance were investigated according to
ASTM-D 5963 using pin on disc machine to present the composite tribological behavior.
The results showed that the mechanical and tribological properties behavior was
improved when the graphite filler content was increased up to 7.5% and then decreased
after that. At 7.5% filler content the modulus of elasticity, yield stress, ultimate tensile
strength, ultimate compression strength and wear resistance increased by (41%, 64%,
24%, 60% and 38%) greater than unfilled composite, while the wear rate was decreased
by 27% less than the unfilled one.

Stress Evaluation of Low Pressure Steam Turbine Rotor bBlade and Design of Reduced Stress Blade

Arkan K. Husain Al-Taie

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 169-179

The low pressure steam turbine blade rows have a history of stress failure . They suffer from
tensile and bending stresses partly due to the centrifugal force as a result of high rotational
speeds and partly due to high pressure, temperature and speed steam loading. The centrifugal
force is one of the problems that face the designers of turbine blades especially the long ones.
The designer always aims at reducing these stresses. One way to do so is by the reduction of blade
mass. That is to make the blade of variable cross section stead in of straight. This paper presents
the method of reducing cross section. Analysis of such blade is also done as applied to the (P 23-
14A) steam blade.

Modeling of Stress-Strain Relationship for Fibrous Concrete Under Cyclic Loads

Bayar J. Al-Sulayfani; Hatim T. Al-Taee

Engineering and Technology Journal, 2008, Volume 26, Issue 1, Pages 45-54

A mathematical model to predict the stress–strain behavior of fibrous concrete composites
under random cyclic compressive loadings is developed. The envelope
unloading strain is used as an index of load history, while the plastic strain and
reloading strain are predicted as functions of the envelope unloading strain for both
full and partial unloading and reloading. The model is independent of the expression
used for the envelope curve. Comparison with cyclic data shows good agreement.
The model can be used for completely random loadings, in both the pre–peak and
post–peak ranges. It is suitable for both plain and fibrous concrete composites. The
model has been built using MATLAB language computer program facilitating the
advanced mathematical
difficulties of solving and differentiating complex expressions.
In this paper, the monotonic stress–strain curves of Al-Sulayfani model [1] for fibrous
concrete had been adopted.