Papers by Alireza Bagheri-Bami
Modares Mechanical Engineering, 2020
The ball deep rolling process is used to improve the surface properties of the workpiece. In this... more The ball deep rolling process is used to improve the surface properties of the workpiece. In this research, the optimum state was determined using the design of the experiment to improve the properties including optimum hardness and roughness. It was determined 3 passes and the type of traditionally and ultrasonic process and proposed regression model at the speed of 1000mm/min. In this case, it showed the hardness of 131 micro vickers and also determined minimum roughness in the mean roughness of 0.179 microns and the maximum roughness of 1.01 microns. The microstructure and tensile tests have been investigated in the optimal sample, compared to the surface topographic reference sample. The microstructure has been shown the decreases from about 30-50 microns to about 300 nanometers in thickness at about 50 microns below the surface by scanning electron microscopy. The tensile stress and percentage increase in length were determined by 10% and 29% increase, respectively by the tensile strength test. Topography has also shown the reduction of roughness by 40%. The hardness of the subsurface was studied in the thickness of the workpiece and it was compared to the same traditional and modern optimum specimen. The result showed the effect of increasing the hardness due to the of the structure fracture and strain rate.
International Journal of Lightweight Materials and Manufacture, 2021
Joining sheets and plates in the industry is of high importance. In the automotive and aerospace ... more Joining sheets and plates in the industry is of high importance. In the automotive and aerospace industry, using friction drilling technique is developing. In order to improve this method, different techniques have been used. In this research, applying ultrasonic vibration on the tool will be investigated. In this regard, a special tool was designed. Axial force and surface hardness were measured in friction drilling and ul-trasonic assisted friction drilling. Higher rotational speed and lower feed rate induce lower axial force and higher surface hardness. In addition, ultrasonic vibration causes the surface to be harder with lower axial force. The results show that increasing the rotational speed and decreasing the feed rate in lathe machine causes axial force reduction and surface hardness increase in heat affect zone and thermo-mechanical region. Moreover, finite element method was carried out which indicated lower axial force occurs in ultrasonic assisted friction drilling comparing to conventional condition. Equivalent plastic strain was used to examine hardness value numerically. The obtained numerical and experiment results were in good agreement.
Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 2019
An increase in bone-implant contact and an increase in surface hydrophilicity are the two importa... more An increase in bone-implant contact and an increase in surface hydrophilicity are the two important factors involved in improving osseointegration. Therefore, three-dimensional elliptical vibration turning method is applied to increase the hydrophilicity of titanium surface by the generation of hierarchical nano-and micro-textures. That being the case, face turning process at different cutting conditions is carried out in this research. Surface roughness and the contact angle of water drops with machined surfaces were selected to be measured for the analysis of surface hydrophilicity. The results show that an additional surface area can be achieved by the generation of micro-or nano-textures, resulting in a lower contact angle. Furthermore, intermittent movement of cutting tool in vibration cutting causes the process to be more stable, achieving the desired range of surface roughness.
A B S T R A C T Ultrasonic assisted ball burnishing process is a newly developed alternative of c... more A B S T R A C T Ultrasonic assisted ball burnishing process is a newly developed alternative of conventional ball burnishing process that enhances the surface properties of engineering materials through imposing both the static and dynamic loadings. The process needs careful selection of design parameters to improve the performance measures such as surface roughness and hardness. In the present study an experimental investigation was carried out to analyze effect of ultrasonic vibration amplitude, feed rate and static force on surface roughness and hardness of aluminum 6061-T6 alloy. Here, number of 20 experiments was carried out through face centered central composite design and values of surface roughness and hardness after each experiment were measured. Hereafter, response surface methodology (RSM) was utilized to correlate empirical relationship between process parameters and responses. Further, numerical simulation of process using ABAQUS software has been carried out to study states of residual stress and plastic equivalent strain under different processing condition. Results indicated that in order to achieve maximum hardness and minimum surface roughness simultaneously, ultrasonic vibration amplitude of 8 µm, feed rate of 1000 mm/min and static force of 38 N, should be selected. The obtained optimal results were then experimentally verified and the prediction errors for both the responses were lower than 10%, implying rigidity of proposed methodology in finding the optimum results. The results obtained by FE simulation showed that the maximum value and effective depth of compressive residual stress in ultrasonic assisted process is significantly higher than that of conventional burnishing.
In the present work, experimental study was carried out to enhance the surface properties
of alum... more In the present work, experimental study was carried out to enhance the surface properties
of aluminum 6061 and AISI 1045 steel plates by ultrasonic assisted ball burnishing process. Full
factorial experimental design was utilized here to find effect ultrasonic vibration, feed rate and
pass number on surface roughness and hardness. The results were discussed according to
Downloaded by [Wilfrid Laurier University] at 23:37 11 August 2017
2
interaction effect of process factors for different material. It is found from the results that for
conventional burnishing process 5000 mm/min feed rate and 5 pass number causes highest
surface hardness; while, for ultrasonic assisted burnishing, the highest hardness is attained at
1000 mm/min feed rate and 5 pass number. On the other hand, it is found from the results that
exerting ultrasonic vibration significantly enhances the hardness value and hardened depth. Also,
it is found that irrespective to type of operation and material, increase of feed rate causes higher
roughness; while, increase of pass number causes reduction of roughness. Furthermore, surface
roughness of ultrasonic assisted burnishing is lower than that of conventional burnishing process.
This enhancement is due to association of both static and dynamic loading in ultrasonic assisted
burnishing process that causes microstructure modification and limits the elastic recovery of the
surface.
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Papers by Alireza Bagheri-Bami
of aluminum 6061 and AISI 1045 steel plates by ultrasonic assisted ball burnishing process. Full
factorial experimental design was utilized here to find effect ultrasonic vibration, feed rate and
pass number on surface roughness and hardness. The results were discussed according to
Downloaded by [Wilfrid Laurier University] at 23:37 11 August 2017
2
interaction effect of process factors for different material. It is found from the results that for
conventional burnishing process 5000 mm/min feed rate and 5 pass number causes highest
surface hardness; while, for ultrasonic assisted burnishing, the highest hardness is attained at
1000 mm/min feed rate and 5 pass number. On the other hand, it is found from the results that
exerting ultrasonic vibration significantly enhances the hardness value and hardened depth. Also,
it is found that irrespective to type of operation and material, increase of feed rate causes higher
roughness; while, increase of pass number causes reduction of roughness. Furthermore, surface
roughness of ultrasonic assisted burnishing is lower than that of conventional burnishing process.
This enhancement is due to association of both static and dynamic loading in ultrasonic assisted
burnishing process that causes microstructure modification and limits the elastic recovery of the
surface.
of aluminum 6061 and AISI 1045 steel plates by ultrasonic assisted ball burnishing process. Full
factorial experimental design was utilized here to find effect ultrasonic vibration, feed rate and
pass number on surface roughness and hardness. The results were discussed according to
Downloaded by [Wilfrid Laurier University] at 23:37 11 August 2017
2
interaction effect of process factors for different material. It is found from the results that for
conventional burnishing process 5000 mm/min feed rate and 5 pass number causes highest
surface hardness; while, for ultrasonic assisted burnishing, the highest hardness is attained at
1000 mm/min feed rate and 5 pass number. On the other hand, it is found from the results that
exerting ultrasonic vibration significantly enhances the hardness value and hardened depth. Also,
it is found that irrespective to type of operation and material, increase of feed rate causes higher
roughness; while, increase of pass number causes reduction of roughness. Furthermore, surface
roughness of ultrasonic assisted burnishing is lower than that of conventional burnishing process.
This enhancement is due to association of both static and dynamic loading in ultrasonic assisted
burnishing process that causes microstructure modification and limits the elastic recovery of the
surface.