2018-09-22T14:25:41Z
http://jcarme.sru.ac.ir/?_action=export&rf=summon&issue=12
Journal of Computational & Applied Research in Mechanical Engineering (JCARME)
JCARME
2228-7922
2228-7922
2012
2
1
Study on tool wear and surface roughness in end milling of particulate aluminum metal matrix composite: Application of response surface methodology
R.
Arokiadass*
K.
Palaniradja
N.
Alagumoorthi
Metal matrix composites have been widely used in industries, especially aerospace industries, due to their excellent engineering properties. However, it is difficult to machine them because of the hardness and abrasive nature of reinforcement elements like silicon carbide particles (SiCp).In the present study, an attempt has been made to investigate the influence of spindle speed (N), feed rate (f), depth of cut (d) and various %wt. of silicon carbide (S) manufactured through stir cast route on tool flank wear and surface roughness during end milling of LM25 Al-SiCp metal matrix composites. Statistical models based on second order polynomial equations were developed for the different responses. Analysis of variance (ANOVA) was carried out to identify the significant factors affecting the tool flank wear and surface roughness. The contour plots were generated to study the effect of process parameters as well as their interactions. The process parameters are optimized using desirability-based approach response surface methodology.
Metal matrix composites (MMC)
Response surface
methodology (RSM)
Flank wear (VBmax)
Surface roughness (Ra)
Contour plots
Optimization
2012
09
11
1
13
http://jcarme.sru.ac.ir/article_35_1867e1d5b63e829579ea676288261a27.pdf
Journal of Computational & Applied Research in Mechanical Engineering (JCARME)
JCARME
2228-7922
2228-7922
2012
2
1
Effect of shell axial deformation on flutter of cantilevered cylindrical shells under follower forces
Mohammad Ebrahim
Torki Harchegani
Mohammad Taghi
Kazemi
Axial vibration effect of shell particles on dynamic stability of a cantilevered cylindrical shell under an axial follower force was addressed. In spite of free-ended shells, the reduced axial force under this effect cannot be derived analytically. Instead, an approximate method was proposed based on the fact that the static (and harmonic) axial deformation under an axial load in a free-ended beam are (almost) zero in a particular point near the middle of the beam, which was adopted as the equivalent fixed end of a cantilever. The work done by the nonconservative follower force was derived for a cantilevered beam and was extended to the case of a cantilevered cylindrical shell. The flutter load for a long free-ended shell was calculated using the equivalent cantilevered half-shell and compared with the previous results. Then, flutter load was calculated with and without the axial vibration effect for cantilevered shells with different lengths and thicknesses and the effect of each parameter was assessed on the flutter load and the critical circumferential mode number in each case.
Axial follower force
Flutter
Cantilevered
cylindrical shell
Circumferential
mode number
2012
09
11
15
24
http://jcarme.sru.ac.ir/article_38_22b6712c6551ae25544748586fead100.pdf
Journal of Computational & Applied Research in Mechanical Engineering (JCARME)
JCARME
2228-7922
2228-7922
2012
2
1
A new positive definite semi-discrete mixed finite element solution for parabolic equations
Zuliang
Lu*
In this paper, a positive definite semi-discrete mixed finite element method was presented for two-dimensional parabolic equations. In the new positive definite systems, the gradient equation and flux equations were separated from their scalar unknown equations. Also, the existence and uniqueness of the semi-discrete mixed finite element solutions were proven. Error estimates were also obtained for the semi-discrete schemes.Finally, a numerical example was presented to show theoretical results.
Parabolic equations
Positive definite systems
Semi-discrete mixed
finite element methods
Error estimates
2012
09
11
25
30
http://jcarme.sru.ac.ir/article_40_7e64016f1fef20f38d3f51637f91756d.pdf
Journal of Computational & Applied Research in Mechanical Engineering (JCARME)
JCARME
2228-7922
2228-7922
2012
2
1
A numerical and experimental study on tubular channel angular pressing (TCAP) as a noble SPD method
Ghader
Faraji*
Mahmoud
Mosavi Mashhadi
Karen
Abrinia
The current study conducted a finite element (FE) and experimental investigation on tubular channel angular pressing as a noble severe plastic deformation technique for producing ultrafine grained and nanostructure tubular components. To examine the effects of the TCAP process on the strain distribution and deformation behavior, FE simulations were employed. The FE results demonstrated that equivalent plastic strain of 2.1-2.9 was developed after applying one pass TCAP. Analytical investigations were carried out to calculate the accumulated strain during the process. Tube thinning in the early stages of the process was observed as a result of tensile circumferential strains but this could be compensated for by the back pressure effect resulting from the next shear zones and also compressive circumferential strain resulting from decreasing the tube diameter. Microstructural observations showed significant grain refinement after one pass TCAP on AZ91 magnesium alloy at 300 ºC. Microhardness measurements demonstrated increasing hardness to 78 HV from the initial value of 51 HV.
Sever plastic deformation
Tubular channel angular pressing
Finite element
Experiments
2012
09
11
31
36
http://jcarme.sru.ac.ir/article_41_f67704b187f3fc5068a442df8b7824ea.pdf
Journal of Computational & Applied Research in Mechanical Engineering (JCARME)
JCARME
2228-7922
2228-7922
2012
2
1
Comparing thermal enhancement of Ag-water and SiO2-water nanofluids over an isothermal stretching sheet with suction or injection
Aminreza
Noghrehabadi
Mohammad
Ghalambaz
Mehdi
Ghalambaz
Afshin
Ghanbarzadeh
In the present paper, the flow and heat transfer of two types of nanofluids, namely, silver-water and silicon dioxide-water, were theoretically analyzed over an isothermal continues stretching sheet. To this purpose, the governing partial differential equations were converted to a set of nonlinear differential equations using similarity transforms and were then analytically solved. It was found that the magnitude of velocity profiles in the case of SiO2-water nanofluid was higher than that of Ag-water nanofluid. The results showed that the increase of nanoparticle volume fraction increased the non-dimensional temperature and thickness of thermal boundary layer. In both cases of silver and silicon dioxide, increase of nanoparticle volume fraction increased the reduced Nusselt number and shear stress. It was also demonstrated that the increase of the reduced Nusselt number was higher for silicon dioxide nanoparticles than silver nanoparticles. However, the thermal conductivity of silver was much higher than that of silicon dioxide.
Nanofluids
Stretching sheet
Thermal enhancement
Wall mass transfer
Analytical solution
2012
09
11
37
49
http://jcarme.sru.ac.ir/article_43_cb6d1db43418f1f9ff68fbff124e26c0.pdf
Journal of Computational & Applied Research in Mechanical Engineering (JCARME)
JCARME
2228-7922
2228-7922
2012
2
1
Applying evolutionary optimization on the airfoil design
Abolfazl
Khalkhali*
Hamed
Safikhani
In this paper, lift and drag coefficients were numerically investigated using NUMECA software in a set of 4-digit NACA airfoils. Two metamodels based on the evolved group method of data handling (GMDH) type neural networks were then obtained for modeling both lift coefficient (CL) and drag coefficient (CD) with respect to the geometrical design parameters. After using such obtained polynomial neural networks, modified non-dominated sorting genetic algorithm (NSGAII) was used for Pareto based optimization of 4-digit NACA airfoils considering two conflicting objectives such as (CL) and (CD). Further evaluations of the design points in the obtained Pareto fronts using the NUMECA software showed the effectiveness of such an approach. Moreover, it was shown that some interesting and important relationships as the useful optimal design principles involved in the performance of the airfoils can be discovered by the Pareto-based multi-objective optimization of the obtained polynomial meta-models. Such important optimal principles would not have been obtained without using the approach presented in this paper.
Multi-objective
Optimization
GMDH
Genetic Algorithm
4-Digit NACA Airfoils
NUMECA
2012
09
11
51
62
http://jcarme.sru.ac.ir/article_46_f7036e5efaff23862489973263df4d1b.pdf
Journal of Computational & Applied Research in Mechanical Engineering (JCARME)
JCARME
2228-7922
2228-7922
2012
2
1
Production method of rubber and sulfur FG composites
S.
Mohammadi*
F.
Abdi
In the presented work, sulfur concrete and rubber were used for producing functionally graded materials (FGM). The physical and mechanical properties of sulfur concrete and rubber were changed continuously across the thickness. On one side, there was just rubber and, on the other, there was pure sulfur; the properties of each substance were moved to reach another. This kind of material was constructed by applying mechanical pressure on all layers together and heating in a casting die. Thus, it is essential to consider the quantity of sulfur and rubber at each layer and the rule obeyed by physical and mechanical properties. In the drop test, it was found that the elastic impact coefficient changed from sulfur concrete around 50% to rubber around near zero. It seems that, by changing some parameters like combination percentage or layers' thickness, it is possible to optimize the FGM.
FGM
SULFUR
RUBBER
COR
2012
09
11
63
69
http://jcarme.sru.ac.ir/article_47_a8b4a98922b48bd7fdcf20b3f1e1e55a.pdf