Showing 13 results for Thickness Distribution
Behrooz Zareh-Dsari, Mohammad Abaszadeh, Behnam Davoodi,
Volume 15, Issue 1 (3-2015)
Abstract
Lubrication is an essential factor in sheet metal forming processes such as deep drawing in order to reduce friction at contact surfaces, forming load, tool wear rate and increasing of sheet formability. Various metal oxide nanoparticles can be used as additives to create desirable tribological properties in base lubricants because of their unique properties such as specific surface area. In the present study, the conventional lubricant enhanced by alumina nanoparticles (Al2O3) is utilized in deep drawing process in order to improve frictional conditions. The forming load, surface roughness (Ra) and thickness distribution values of the formed cups were assessed to evaluate the performance of the enhanced conventional lubricant with alumina nanoparticles (Al2O3) in comparison to the conventional lubricant and dry forming condition. The obtained results from experimental tests revealed that adding 0.5 wt.% Al2O3 nanoparticles to the conventional lubricant improves lubrication property significantly and reduces forming load by 16.39% and surface roughness by 19.33% compared to the conventional lubricant. Furthermore, it is observed that using lubricant containing nanoparticle additives results in 23.94% improvement in maximum thickness reduction in critical zone.
Mohammad Hosseinpour, Abdolhamid Gorji, Mohammad Bakhshi,
Volume 15, Issue 2 (4-2015)
Abstract
Aluminum alloys have high strength to weight ratio and Poor formability at room temperature is the main drawback of using these alloys. In order to overcome this limitation, the work material is formed at higher temperature. One of the forming processes is hydrodynamic deep drawing on which no relevant research has been reported in warm condition. In the present paper, after examining the formability of 5052 aluminum alloy in warm hydrodynamic deep drawing, the effect of media pressure, temperature and forming speed on thickness distribution and punch force in forming of flat-bottom cylindrical cups was investigated. In order to perform a complete investigation, the simulation of the process was established using ABAQUS software. It was illustrated that the results was in accordance with the experimental findings. It was also demonstrated that increasing the maximum oil pressure to a specified level could improve the thickness distribution and lead to increasing the punch force. The required punch force was decreased with increase in temperature but remained unchanged by punch speed variation. The maximum thickness reduction was decreased with increasing and decreasing of temperature and punch speed, respectively. Moreover, the forming of the sheet at room temperature, isothermal and non-isothermal warm forming processes was compared. It was concluded that the maximum thickness reduction in the formed part was less in the cases of cold forming and non-isothermal warm forming than the isothermal warm forming. But the required forming force is decreased in isothermal warm forming when compared with the other two conditions.
Abdolhamid Gorji, Esmaeil Mohammadian, Mohammad Ali Mirzai,
Volume 15, Issue 4 (6-2015)
Abstract
Forming media in metal forming processes is so important. Since the forming media in Ball deep-drawing process is discrete, it is quite flexible. In this paper, thickness distribution and required force for forming of conical part by ball deep-drawing and conventional deep-drawing processes using finite element simulation and experimental stages, were studied. In this research, sheets were used made St14 steel and brass wit 1mm thickness. The experimental results are in good agreement with simulation results. The results showed the sample formed by conventional deep-drawing process had more uniform thickness distribution than ball deep-drawing, but the maximum thinning in the parts of ball forming process was less than conventional deep-drawing process. Also it was observed that required force for ball deep drawing process is more than the conventional deep-drawing process. It was observed that with increasing radius of the input die, the force required to stretch the ball deep-drawing and ball processes is decreased, also with increasing radius of the input die is reduced thinning amount. It was noted that one of the advantages of ball deep drawing process than traditional deep drawing process is achieved a negative slope part.
Ali Fazli, Mohammad Reza Hosseini,
Volume 15, Issue 11 (1-2016)
Abstract
Electrohydraulic forming (EHF) is a high velocity forming process in which the electric energy stored in the capacitors are suddenly discharged between two electrodes submerged in a water-filled chamber. During the discharge, the water between the electrodes vaporizes and creates a shock wave that is transferred to the blank using the water and forms it. One of the key parameters in electrohydraulic forming is the determination of the suitable position of the electrodes. In this research the effect of electrodes position in electrohydraulic free-forming is investigated using the finite element simulation. First the experiments available in the literature is simulated using the software ABAQUS/ Explicit and compared with the experimental results which shows good agreement with. Then by changing the position of the electrodes, the effect of their position on the formability and thickness distribution of the blank is investigated. The results indicates that the forming a component is only possible in limited positions of the electrodes and there is a position for the electrodes that not only improves the sheet thickness but also decreases the possibility of the failure.
Majid Elyasi, Farzad Ahmadi, Morteza Hosseinzadeh,
Volume 15, Issue 12 (2-2016)
Abstract
Rubber pad forming is a practical and low-cost method of producing metal bi-polar plates with complicated multi- array contours since it only needs a rigid die and a flexible rubber. In this study, 316 stainless steel sheets with the thickness of 0.1 mm were used. To form the plates, a polyurethane rubber was used with the hardness shore of A 85 with the thickness of 25 mm. In order to increase the depth of the channel flow and form filling plates with a high depth-to-width ratio, firstly, the effects of lubricants on shaping metal plates were ignored. Subsequently, by implementing lubricants, their effects on achieving a higher filling depth and a more uniform thickness distribution were investigated. The results showed that in rubber pad forming process, lubricants could be used to further enhance the depth of filling and have a uniform thickness distribution in the channels of generated plates. Moreover, among available lubricants, polypropylene nylon will be the best alternative for the production of bipolar plates due to its high tensile strength and low thickness.
Seyyed Ahmad Eftekhari, Ali Fazli,
Volume 16, Issue 7 (9-2016)
Abstract
The incremental forming process which can be used in low quantity production of the components is a relatively new forming process for sheet metal components. One of the problems of this method is thinning and non-uniform thickness distribution of the component in radial direction. In the incremental forming process, the sheet thickness in the wall of the formed cup is reduced considerably while the thickness in the bottom of the formed cup is unchanged. This problem is hindering the wide application of the incremental forming process in the industry. In this paper, a new method is presented for the improvement of the thickness distribution in the incremental forming process. In the presented method, a new preform is added to forming stages which reducing the sheet thickness in the bottom of the formed cup, increases the minimum thickness in the wall of the formed cup and improves its thickness distribution. The incremental forming process are simulated using the software ABAQUS and verified using the experiments available in the literature. Then the proposed method is simulated which its result indicates the capability of the presented method in thickness improvement.
Reza Rajabiehfard, Abolfazel Darvizeh, Majid Ali Tavoli, Hamed Sadeghi, Majid Moghadam, Naser Noorzadeh,
Volume 16, Issue 12 (2-2017)
Abstract
In this paper, the behavior of cylindrical shells with uniform thickness and functionally graded thickness distributions subjected to axial quasi-static loading is investigated experimentally and subjected to axial impact is investigated experimentally and numerically. Steel cylindrical shells with uniform thickness and functionally graded thickness distributions have same inner diameter, length and weight. Cylindrical shells are impacted by the drop hammer apparatus and experimental axial force-time curves are obtained by using a load cell; in addition, impact simulations are done by Abaqus finite element software. The effect of thickness distributions on the shortening, energy absorption, buckling shape and axial force-time curve of cylindrical shells is investigated. It is found that for axial quasi-static loading, a change in thickness distribution of cylindrical shell is able to convert the buckling shape from mixed buckling (a combination of axisymmetric and diamond modes) to progressive buckling, also for axial impact loading, a change in thickness distribution of cylindrical shell can affect the number of complete folds. The studies also suggest that at same impact energy, functionally graded thickness distribution cylindrical shell compared with uniform thickness distribution cylindrical shell absorbs approximately the same energy with more shortening and transforms less mean load and peak load to under protected specimen, thus, functionally graded thickness distribution cylindrical shell is a better energy absorption specimen. It is found that there is a good agreement between the experimental and numerical results.
Mehdi Karimi Firouzjaei, Hassan Moslemi Naeini, Hamidreza Farahmand, Behnam Abbaszadeh, Mohammadmehdi Kasaei,
Volume 17, Issue 10 (1-2018)
Abstract
In this paper, cold roll forming process of a high strength steel pipe using four types of flower pattern including circular, edge, double radius and reverse bending is simulated with finite element method in MSC Marc Mentat software. Due to importance of quality of final pipe and in order to achieve the desired geometry in high strength steel pipes, selecting the appropriate flower pattern to design the pipe roll forming production line is considered. Using finite element simulation results, deformation of sheet in this process is studied and effect of flower pattern type on geometry of final product, which includes curvature distribution, spring back and thickness distribution of pipe, is investigated. Results show that implementing reverse bending flower pattern, leads to reduction in deviation from mean curvature at edge of the sheet up to about 65 percent. Thickness distribution analysis shows that circular and edge flower patterns cause upsetting and thinning of edge of the sheet up to 0.2 millimeters, respectively. But, use of double radius and reverse bending patterns cause average thickness of edge to be well adjusted to reach 2.8 millimeters. Also, circular flower pattern has the lowest value of spring back in terms of variation of mean relative curvature of 0.69 percent and edge deviation of 0.15 millimeters. To validate the finite element simulation, experimental tests were designed and conducted using one forming stand. By comparing resultant data of experimental tests with simulation results, validity of finite element simulation confirmed.
Payam Tayebi, Ali Fazli, Parviz Asadi, Mahdi Soltanpour,
Volume 18, Issue 3 (5-2018)
Abstract
In this paper, the single point incremental forming (SPIF) of friction stir welded (FSWed) 5083 aluminum alloy sheets are investigated experimentally and numerically. The aluminum sheets with 2mm thickness are friction stir welded with the same FSW parameters. In order to obtain the effect of FSW on the formability of SPIF, the base sheets and FSWed sheets are formed to conical shapes with different forming angles and then the limiting wall angles are determined for each condition. The experimental results indicate that the limiting forming angle of FSWed sheet is not so much different than the base sheet and FSW does not have a negative effect on the sheet metal formability in SPIF. To study the effect of SPIF and FSW in mechanical and microstructural properties of the formed parts, the effects of these process on the grain size and micro-hardness is investigated. Furthermore, the incremental forming is numerically simulated using the ABAQUS software and the sheet thickness distribution, obtained from the simulation, is compared with the experimental results. After verification of the numerical simulation model, the effect of FSW on the thickness distribution and strain distribution in SPIF is studied. The results indicate that in weld region and base metal region, the distributions of thickness and major strain are uniform while the distribution of minor strain is non-uniform.
M.h. Shojaeifard, A. Sajedin, A. Khalkhali,
Volume 19, Issue 11 (11-2019)
Abstract
Turbocharger turbine blade thickness is restricted by blockage and trailing edge losses and it is exposed to damage due to aerodynamic loads. Proper designing of the blade needs to full recognition of loads on the blade. Therefore, the force from the fluid to the blade should be calculated. Although, thickening the blade results to the more resistance to fracture and cracks, but it affects the aero-structural performance of each section of the blade differently. So, turbocharger turbine blades are exposed to pulsating flow which should be considered in thickness distribution selection. This article reports a comprehensive fluid-solid interaction study of the turbine blades with different thickness distribution which could beneficially investigates the effect of each part thickness on the aerostatic efficiency. Leading edge and trailing edge thickness, maximum thickness and its location, trailing edge shape, hub, and tip blade thickness were the variables which their effects were investigated. Using dual turbocharger turbines leads to lower dissipation of kinetic energy of pulsating charge from the engine. In such turbines, each sector of rotor accepts a different charge from upper and lower entries. The flow distribution of every passage is the difference from the others. Therefore, to the evaluation of the flow, modeling of the entire turbine is needed. 3D CFD model in ANSYS CFX for fluid side and an FEA model in ANSYS Static Structural module for the blade structural responses were used then the results were coupled. Validation was performed by reference to experimental data carried out in imperial college London on a dual turbocharger turbine.
B. Soltani, M. Babaeian, H. Ghasemi,
Volume 20, Issue 7 (6-2020)
Abstract
Incremental forming method with lower cost and more flexibility can be a suitable alternative for traditional methods of the hole-flanging. In this study, the possibility of square hole-flanging of AL1050 aluminum sheet using incremental forming method has been investigated and the quality of the pyramid flange has been compared with conical flange. The final shape of the flange is defined so that wall angle increases with raising height. The process simulation was performed using Abaqus software and an experimental test was done to validate the simulation results. After performing the experimental tests, flange features such as the final size of the hole, flange height, and wall thickness were measured. The results showed that at the created flange around the circular hole, there is less spring back and more dimensional accuracy, however, it can be flanged a square hole by incremental approach with consideration of the height and hole size. The dimensional measurements showed that the final size of the hole will increase after the hole-flanging. By investigation of the various holes, it was found that in the larger initial hole, increasing the hole size after the flanging will be lower.
Hamid Reza Ghahreman, Mohammad Honarpisheh, Mohammad Bagher Sarafrazi,
Volume 22, Issue 5 (4-2022)
Abstract
One of the forming pipes methods is the rotary draw bending process. Today, bending of thin-walled pipes with low radius of curvature is widely used in the automotive, military and aerospace industries, which is used to bend high-strength pipes. In this paper, at first the necessary models were created to simulate the bending process of the rotary pipe, and then the necessary mechanical and physical properties for stainless steel 304 and elastomers were determined. Then, experimental and numerical study of the forming force and changes in pipe wall thickness were performed. The process simulation was analytically performed using polyurethane elastomeric mandrels and nitrile rubber based on ABAQUS finite element software on 304 steel. The results show a good agreement between simulation and experimental results. Finally, the effects of process parameters including mandrel type, pipe diameter and bending radius were analyzed on the maximum forming force by factorial analysis. The results showed that the maximum forming force for both types of mandrel materials is obtained for pipes with small diameter and high curvature radius. Also, the bending forces increase 5 times by 30%increasing the bending radius, for pipes with smaller diameters. In addition, in equal diameter and radius of bending, the bending forces in the case of using polyurethane mandrel are 25% more than nitrile mandrel.
Fatemeh Taghizadeh Rami, Majid Elyasi,
Volume 22, Issue 6 (5-2022)
Abstract
In this study, bending of titanium tubes using steel balls in 0.5 and 0.85 mm sizes and resistance heating with experimental and simulation methods have been investigated. In order to apply temperature in rotatory draw bending of tubes, electric current cables were connected to both sides of the tube, and experiments were performed at room temperatures, 100℃, 200℃, 300℃ and 400 ℃ with a bending ratio of 1.8 and a bending angle of 90 ° was done. After the experiments, cross-sectional distortion, wrinkles, cracking and thickness distribution of bent tubes were investigated. The results of this study showed that in the case of bending at room temperature with and without metal balls, the tubes could not be bent. In the bending process with a constant speed of 0.8 Rad/s, by placing metal balls inside the tube and increasing the temperature 100℃, 200℃ and 300℃, the thickening in the intrados of the bent tube decreased by 9.8% and the thinning at the extrados of the bent tube increased by 8.4%. Also, by changing the bending speed from 0.8 to 0.4 Rad/s the cracking defect was eliminated at 400℃. Due to increased pressure due to steel balls in bending area, cross section distortion in tubes decreased by 10.4%. The best bending conditions and the least amount of defects were obtained at 300℃ with steel balls.
