Journal of Mechanical Engineering Research
EISSN : 2630-4945
Current Publisher: Bilingual Publishing Co. (10.30564)
Total articles ≅ 30
Latest articles in this journal
Journal of Mechanical Engineering Research, Volume 4; doi:10.30564/jmer.v4i1.2643
In this study, two dimensional unsteady flow of cylinder and cylinder with additional fairing close to a free surface was numerically investigated. The governing momentum equations were solved by using the Semi Implicit Method for Pressure Linked Equations(SIMPLE). The Volume of Fluid(VOF) method applied to simulate a free surface. Non- uniform grid structures were used in the simulation with denser grids near the cylinder. Under the conditions of Reynolds number 150624, 210874, 210874 and 331373, the cylinders were simulated with different depths of invasion. It was shown that the flow characteristics were influenced by submergence depth and Reynolds numbers. When the cylinder close to the free surface, the drag coefficient, lift coefficient and Strouhal numbers will increase due to the effect of free liquid surface on vortex shedding. With additional fairing, can effectively reduce the influence of the free surface on the drag coefficient. Fairing will reduce lift coefficient at high Reynolds numbers, but increase lift coefficient when Reynolds numbers is small. Fairing can effectively reduce Strouhal numbers, thus can well suppress the vortex induced vibration.
Journal of Mechanical Engineering Research, Volume 4; doi:10.30564/jmer.v4i1.2890
The aim of this work is to establish the influence of the relative position of the alloy charge C-Cr-Mn in the structure of the coating of rutile electrodes for hardfacing, on the operational behavior (arc stability). For this, three variants of electrodes with similar chemical composition are elaborated in the metallic core and the coating, differentiating only in the relative position that occupies the alloy charge (C-Cr-Mn) in the structure of the coating: internal, external and homogeneous. For the development of the research a completely random design is used. The operative characterization of the electrodes is performed in terms of the arc stability. In conclusion, it can be seen that the position of the alloy load influences the operation behavior (stability of the arch). The variant of internal alloy charge in the coating presents the better arc stability performance.
Journal of Mechanical Engineering Research, Volume 4; doi:10.30564/jmer.v4i1.2940
Today ultrasonic power technique is consider a mandatory technique which is always entered in many processes such as in metal and plastic welding to overcomes many issues, with aided of applying force (pressure) and supplied high frequency vibration, a solid-state weld can be generated by ultrasonic metal welding technique. That give a technique the ability to join not only a small components, whereas also to join thicker specimens, depend on a proper control of matching welding conditions. Therefore a welding performance can be study and compared after designed welding horn to resonance at frequencies of 20 kHz and 40 kHz. The analyses of the designed horn are completed through use a vibration mathematical expressions, modal and harmonic analyses to ensure the weldability due to applying ultrasonic power to the working area and also to compare the performance of joint at using two resonance frequencies of 20 kHz and 40 kHz. The dimensions of the horns were determined to match the selected resonance frequencies, which the lengths were calculated as 132 mm and 66 mm respectively. The analysis of the exciting modal indicates that the axial vibration modes of 19,584Hz and 39,794Hz are obtained in 10th mode, while the two frequency values are recorded 19,600 Hz and 39,800 Hz from the frequency response of the two horns. The weld strength between Al and Cu specimens with a thickness 0.5 mm were evaluated using tensile test, which the analyses were obtained under using different welding pressure and varied amplitudes. The results were recorded within exciting a horn with two different resonance frequencies, show the enhancement of weld strength and quality through control of stepping amplitude, the enhancement means obtain good strength of the weld, reduce sticking horn to specimen, and lower specimen marking.
Journal of Mechanical Engineering Research, Volume 4; doi:10.30564/jmer.v4i1.2889
Concepts of precision engineering design process for optimal design where engineering sciences contribute in the successful good design are elaborated in this paper. Scientific theory, numerical methods and practicality are discussed in this paper. Factors necessary for a complete product or systems design are detailed and application of mathematical design optimization in producing a good design are shown. Many applicable engineering design examples are itemized to show relevancy of the optimal design theory to engineering design. Future trends of optimal design with respect to the 4th industrial revolution of digitization is presented. Paper sets to elaborate that most of the engineering and scientific design problems can be optimized to a good design based on many new/advanced optimization techniques.
Journal of Mechanical Engineering Research, Volume 3; doi:10.30564/jmer.v3i2.1737
Fly Ash Cenospheres (FACs) are obtained from the coal power plants in the form of hollow spherical particles by burning the coal. FAC was started to use in early 1980-1985 as lightweight filler material in producing composites of cementitious and at present many researchers are focusing on use of FAC as filler in polymer and metals. In this paper, the systematic review on research activities and application of FAC in manufacturing light weight products are done. The FAC influence on the mechanical and physical properties of incorporated polymer and alloy based composites were summarized. Prospects of future for its use were also suggested and summarized in this paper.
Journal of Mechanical Engineering Research, Volume 3; doi:10.30564/jmer.v3i2.1903
As the market competition of steel mills is severe, deoxidization alloying is an important link in the metallurgical process. To solve this problem, principal component regression analysis is adopted to reduce the dimension of influencing factors, and a reasonable and reliable prediction model of element yield is established. Based on the constraint conditions such as target cost function constraint, yield constraint and non-negative constraint, linear programming is adopted to design the lowest cost batting scheme that meets the national standards and production requirements. The research results provide a reliable optimization model for the deoxidization and alloying process of steel mills, which is of positive significance for improving the market competitiveness of steel mills, reducing waste discharge and protecting the environment.
Journal of Mechanical Engineering Research, Volume 3; doi:10.30564/jmer.v3i2.1774
According to formula we can simulate their driven force and acceleration. The mechanical formula is used to obtain dynamics is used to simulate. The driven force increases when torque increases and tire diameter decreases. We need torque to increase so this is our plan. Acceleration raises when torque raises and it reduces when its weight raises. With the decreasing of radius of road the centripetal acceleration is increasing in the condition of light vehicle. It is that it decreases sluggishly before 0.35m/s2 then it maintains a steep decline to 0.62m/s2 and at last becomes sluggish again. It is valued that the economical efficiency about consumed fuel under different power. In the time of 0.2hr the fuel inflamer inclines sharply first then turns stable. It is the smallest value. Beyond it the fuel maintains a high value all the time. The discharged pollution gas decreases with the decreasing initial temperature. The low initial temperature is good to fuel gas. Meantime the smallest incline range is 300~350K which explains that it is the most save one.
Journal of Mechanical Engineering Research, Volume 3; doi:10.30564/jmer.v3i2.1800
According to formula we can simulate their driven force and acceleration on the slope. The mechanical formula is used to obtain force and theoretical dynamics in the slope. The driven force decreases when rotation increases. When power increases the acceleration increases. it reduces when its weight raises. It is found that the a will decrease as slope becomes high from 5 to 11° to 22°, which fit the formula too. Meantime as the radius is high from 0.3m to 0.4m to 0.47m a will be low. The needed force will increase as the slope decline becomes big at the same power.
Journal of Mechanical Engineering Research, Volume 3; doi:10.30564/jmer.v3i1.1568
One of the innovative ways to improve heat transfer properties of heat exchangers, is using nanofluids instead of traditional fluids. Due to presence of metal and oxides of metal particles in nanofluids structure, they have better potential in different environments and conditions than conventional fluids and having higher thermal conductivity causes improvements in heat transfer properties. In this research flow of two different nanofluids through a rectangular microchannel consisting of different number of longitudinal vortex generators (lvgs), has been investigated. Simulations conducted under laminar flow boundary condition and for different Reynolds numbers from 100 to 250. Considered volumetric concentration in this paper is 1, 1/6 and 2/3 %. Results showed, nanofluids and the LVGs remarkably enhance the heat transfer rates inside the microchannel. havg improved with increasing the nanoparticles volume concentrations and Reynolds number, whereas the opposite trends observed for pressure drop. havg improved for 4 to 12 and 9 to 18% for TiO2 and CuO nanofluids, respectively for different volume concentrations in simple microchannel. For lvg-enhanced microchannel the amount of improvements is about 9-14 and 5-10% for CuO and TiO2, respectively. Also using vortex generators alone improved havg for 15-25% for different number of lvgs.
Journal of Mechanical Engineering Research, Volume 3; doi:10.30564/jmer.v3i1.1716
It is well-known that suspension systems plays a major role in automotive technology. Most of the today’s vehicle applies a passive suspension systems consisting of a spring and damper. The design of automotive suspension have been a compromise between passenger comfort, suspension travel and road holding ability. This work aims in reducing the suspension travel alone by developing a quarter car model suspension for a passenger car to improve its performance by introducing shape memory alloy spring (Nitinol) instead of traditional spring. A two way shape memory alloy spring possesses two different stiffness in its two different phases (martensite and austenite). In this study, road profile is considered as a simple harmonic profile and vibration analysis of aminiature quarter car model suspension system has been carried out experimentally. Using theoretical method, the displacement of the sprung mass is also studied and discussed. The vibration analysis have been carried out for the suspension system at both phases of the spring and the results gives a significant improvement in reducing the displacement of sprung mass for various excitation frequencies.