This research article interprets the computational fluid dynamics analysis on blood flow inside a... more This research article interprets the computational fluid dynamics analysis on blood flow inside a symmetric stenosed artery. The current problem models the blood flow inside the left coronary artery as having a symmetric stenosis in the central region. A comprehensive physiological examination of coronary artery disease is numerically evaluated by using the computational fluid dynamics toolbox Open-Field Operation And Manipulation. There are no assumptions of mild stenosis taken into account since the considered stenosis has an exactly measured length, height and position, etc. The blood flow problem is modeled for the non-Newtonian Casson fluid with unsteady, laminar, and incompressible flow assumptions. The underlying problem is solved numerically in its dimensional form. A thorough graphical analysis is provided on the blood flow simulations, pressure profile, velocity line graphs, pressure line graphs, and streamlines for the left coronary artery having a symmetric stenosis form...
1 Figure 1 Taniguchi’s plot of the historical progress of achievable machining accuracy over the ... more 1 Figure 1 Taniguchi’s plot of the historical progress of achievable machining accuracy over the past century [1]. Abstract: The internal mechanism of conventional contact-gauging instruments, namely mechanical dial and electronic indicators, is a potential source of errors. Tests performed on some high-accuracy indicators revealed systematic effects of spring rate and substantial force variations in both directions. Stick-slip friction forces of bearing and wiper caused additional variations. Analyses of contact confirmed that these force uncertainties can generate contact uncertainties well above the level of concern on common conditions of engineering surfaces. A new consideration in the analyses of the measurement error budget of these instruments is introduced here. The potential errors induced by the complex behaviour of contact between measuring probe tips and engineering surfaces are of concern in this study. These potential errors are usually neglected by researchers.
IOP Conference Series: Materials Science and Engineering, 2019
Scarf adhesive joints (SAJs) have attracted an increasing attention in joining/repairing of carbo... more Scarf adhesive joints (SAJs) have attracted an increasing attention in joining/repairing of carbon-fiber reinforced epoxy (CFRE) composite structures due to their zero eccentricity, which provides better aerodynamic surfaces. This study evaluated for the first time, the performance of SAJs in CFRE composites under thermo-mechanical impact loads. The adhesive was modified with optimum percentage of multi-walled carbon nanotubes (CNTs). The impact tests were performed at room temperature of +25°C, +50°C and +75°C. The residual flexural properties of the unfailed impacted joints were measured using three-point bending test. Results from impact tests at temperature of 25°C, 50°C and 75°C showed improvement in the impact bending stiffness of the modified SAJs with CNTs by 8.3%, 7.4% and 11.8% and maximum contact force by 15.6%, 21.3% and 18.9%, respectively. The energy at failure of the CNT-SAJs was increased by 15.2% and 16.4% respectively at temperatures of 25°C and 50°C. At test tempe...
Due to the influence of the manufacturing process on the composite’s wear properties, mathematica... more Due to the influence of the manufacturing process on the composite’s wear properties, mathematical models cannot accurately predict the wear rates and coefficients of friction of composite materials. As a result, this work provides a deeper comprehension of the tribological properties of Al-TiO2 nanocomposites with varying TiO2 content tested at varying sliding loads as well as improved predictability. Accumulative roll bonding (ARB) was used to create Al-TiO2 nanocomposites that had good TiO2 nanoparticle dispersion in the matrix. The pin-on-disc test was used to measure their wear rates and coefficient of friction. A neural network model was used to predict the wear rates and the coefficient of friction because there was a correlation between the composite morphology, hardness, and microstructure, as well as the evolution of the tribological properties. Due to the uniform distribution of TiO2 nanoparticles within the composite and the saturation of grain refinement in the Al matri...
In this paper, we present a newly modified machine learning model that employs a long short-term ... more In this paper, we present a newly modified machine learning model that employs a long short-term memory (LSTM) neural network model with the golden jackal optimization (GJO) algorithm to predict the tribological performance of Cu–Al2O3 nanocomposites. The modified model was applied to predict the wear rates and coefficient of friction of Cu–Al2O3 nanocomposites that were developed in this study. Electroless coating of Al2O3 nanoparticles with Ag was performed to improve the wettability followed by ball milling and compaction to consolidate the composites. The microstructural, mechanical, and wear properties of the produced composites with different Al2O3 content were characterized. The wear rates and coefficient of friction were evaluated using sliding wear tests at different loads and speeds. From a materials point of view, the manufactured composites with 10% Al2O3 content showed huge enhancement in hardness and wear rates compared to pure copper, reaching 170% and 65%, respective...
Wettability between Cu and Al 2 O 3 nanoparticles is relatively low, which limit the applicabilit... more Wettability between Cu and Al 2 O 3 nanoparticles is relatively low, which limit the applicability of this nanocomposite. To this end, electro-less deposition of Ag over Al 2 O 3 nanoparticles were applied to improve their wettability with Cu matrix. Al 2 O 3 coated Ag were mixed with commercially pure Cu powder in varying weight percentages (0, 2, 4, 6 and 8) and then nanocomposites were synthesized through powder metallurgy route. To obtain uniform distribution of nanoparticles in Cu matrix, mixing was carried out via mechanical alloying. Microstructure, mechanical and wear behaviors were investigated to see the effect of Al 2 O 3 nanoparticles content in Cu. The result showed that Al 2 O 3 nanoparticles are homogenously dispersed in the Cu matrix. The hardness and compressive strength were improved by the addition of nanoparticles up to 8 wt%. Around 30% improvement was found in the strength of the nanocomposite. Furthermore, the average hardness of the composite coatings varies from 65.2 to 150 HV as Al 2 O 3 content increases from 0 to 8 wt%. Abrasive wear analysis showed that the abrasive wear resistance of the nanocomposites improves with the increment of nanoparticle content. The microstructure refines due to Al 2 O 3 addendums illustrated a considerable function in the wear behavior of the Cu matrix.
Aluminum (Al) composites have been extensively developed for automotive applications due to their... more Aluminum (Al) composites have been extensively developed for automotive applications due to their high specific strength. Therefore, in this study, an Al-titanium dioxide (TiO2) nanocomposite was processed using the accumulative roll bonding (ARB) process. The mechanical characteristics of monolithic and nanocomposites specimens made with 0, 1, 2, and 3 wt% TiO2 nanoparticles as reinforcement were studied at several ARB passes. According to the microstructure of the composites, rolling after five passes achieves a homogenous distribution of reinforcement particles, ultrafine and elongated grains of the matrix. After five ARB passes, the TiO2 particles were uniformly dispersed. Finally, scanning electron microscopy and energy dispersive spectroscopy revealed that the Al-TiO2 nanocomposite had an appropriate dispersion of TiO2 nanoparticles. Vickers microhardness improves as the number of accumulative roll bonding passes increases. Furthermore, after five passes, Vickers microhardness...
This paper presents a machine learning model to predict the effect of Al2O3 nanoparticles content... more This paper presents a machine learning model to predict the effect of Al2O3 nanoparticles content on the wear rates in Cu-Al2O3 nanocomposite prepared using in situ chemical technique. The model developed is a modification of the random vector functional link (RVFL) algorithm using artificial hummingbird algorithm (AHA). The objective of using AHA is used to find the optimal configuration of RVFL to enhance the prediction of Al2O3 nanoparticles. The preparation of the composite was done using aluminum nitrate that was added to a solution containing scattered copper nitrate. After that, the powders of CuO and Al2O3 were obtained, and the leftover liquid was removed using a thermal treatment at 850 °C for 1 h. The powders were consolidated using compaction and sintering processes. The microhardness of the nanocomposite with 12.5% Al2O3 content is 2.03-fold times larger than the pure copper, while the wear rate of the same composite is reduced, reaching 55% lower than pure copper. Thes...
This paper presents a machine learning model to predict the effect of Al2O3 nanoparticle content ... more This paper presents a machine learning model to predict the effect of Al2O3 nanoparticle content on the coefficient of thermal expansion in Cu-Al2O3 nanocomposites prepared using an in situ chemical technique. The model developed is a modification of Long Short-Term Memory (LSTM) using dwarf mongoose optimization (DMO), which mimics the behavior of DMO to find its food for predicting the behavior of the composite. The swarm of DMO consists of three groups, namely the alpha group, scouts, and babysitters. Each group has its own behavior to capture the food. The preparation of the nanocomposite was performed using aluminum nitrate that was added to a solution containing scattered copper nitrate. After that, the powders of CuO and Al2O3 were obtained, and the leftover liquid was removed using thermal treatment at 850 °C for 1 h. The powders were consolidated using compaction and sintering processes. The impact of Al2O3 contents on the thermal properties of the Cu-Al2O3 nanocomposite wa...
This investigation explores the behaviour of contact interaction between probe tips of indicators... more This investigation explores the behaviour of contact interaction between probe tips of indicators (displacement gauges) and rough engineering surfaces, in order to gain new insights into uncertainty in industrial precision gauging. The conditions of interest are contact of a mm-scale hard sphere at 0.1 to 5 N force with metallic surfaces, Rq < 2 mm. The motivation arises from the growing demand of modern industries for higher machining processes and for finer inspection capabilities. In the near future, such a demand is likely to require careful analyses of the measurement error budget of these instruments with a greater consideration of the potential errors induced by the complex behaviour of contact, which is currently assumed to be negligible. A preliminary experimental study was carried out on an existing test-rig of limited accuracy. It raised several concerns related to the effects of surface roughness and material on the resulting contact deflection at the load regimes of ...
This manuscript aims to study the effects of drilling factors on the thermal-mechanical propertie... more This manuscript aims to study the effects of drilling factors on the thermal-mechanical properties and delamination experimentally during the drilling of glass fiber reinforced polymer (GFRP). Drilling studies were carried out using a CNC machine under dry cutting conditions by 6 mm diameter with different point angles of ∅ = 100°, 118°, and 140°. The drill spindle speed (400, 800, 1600 rpm), feed (0.025, 0.05, 0.1, 0.2 mm/r), and sample thickness (2.6, 5.3, and 7.7 mm) are considered in the analysis. Heat affected zone (HAZ) generated by drilling was measured using a thermal infrared camera and two K-thermocouples installed in the internal coolant holes of the drill. Therefore, two setups were used; the first is with a rotating drill and fixed specimen holder, and the second is with a rotating holder and fixed drill bit. To measure thrust force/torque through drilling, the Kistler dynamometer model 9272 was utilized. Pull-in and push-out delamination were evaluated based on the ima...
ABSTRACT Among the most important elements in aircraft structures are joints for transferring loa... more ABSTRACT Among the most important elements in aircraft structures are joints for transferring loads. An accurate assessment of the stresses for joints is essential for reliable strength evaluation and failure prediction. The aim of this work is to compare different types of materials, i. e. isotropic, laminated, and functionally graded materials (FGM), and different types of laminates, considering the ratio of stresses generated around a hole in a plate and the applied stress. The finite element method (FEM) is used to evaluate the stresses around a hole for the three types of materials when the plate is subjected to tensile stress, heating, and both heating and tensile stress. Utilizing the ANSYS package, the target of the study was to investigate the validity of the method. The results obtained for the laminated plate are compared to those obtained by E. Pan, and Rybiki &amp; Hopper for both (90/0)s and (–45/45)s laminates. By similar results, it was shown that the laminates can withstand loads better than isotropic materials or FGM.
Since the introduction of aseptic surgery by Lister towards the end of the eighteenth century, en... more Since the introduction of aseptic surgery by Lister towards the end of the eighteenth century, engineering materials have been implanted into the human body in many forms. Implant surgery has developed to the extent that implants are now used in most branches of surgery and are becoming increasingly more sophisticated. Orthopaedic surgery probably uses more implants than any other branch of medicine. Fracture fixation being one of the oldest and most common applications. This literature review tries to inclusively summarize the recent development in bio-medical materials and its applications in human joint implants up to year 2010.
This research article interprets the computational fluid dynamics analysis on blood flow inside a... more This research article interprets the computational fluid dynamics analysis on blood flow inside a symmetric stenosed artery. The current problem models the blood flow inside the left coronary artery as having a symmetric stenosis in the central region. A comprehensive physiological examination of coronary artery disease is numerically evaluated by using the computational fluid dynamics toolbox Open-Field Operation And Manipulation. There are no assumptions of mild stenosis taken into account since the considered stenosis has an exactly measured length, height and position, etc. The blood flow problem is modeled for the non-Newtonian Casson fluid with unsteady, laminar, and incompressible flow assumptions. The underlying problem is solved numerically in its dimensional form. A thorough graphical analysis is provided on the blood flow simulations, pressure profile, velocity line graphs, pressure line graphs, and streamlines for the left coronary artery having a symmetric stenosis form...
1 Figure 1 Taniguchi’s plot of the historical progress of achievable machining accuracy over the ... more 1 Figure 1 Taniguchi’s plot of the historical progress of achievable machining accuracy over the past century [1]. Abstract: The internal mechanism of conventional contact-gauging instruments, namely mechanical dial and electronic indicators, is a potential source of errors. Tests performed on some high-accuracy indicators revealed systematic effects of spring rate and substantial force variations in both directions. Stick-slip friction forces of bearing and wiper caused additional variations. Analyses of contact confirmed that these force uncertainties can generate contact uncertainties well above the level of concern on common conditions of engineering surfaces. A new consideration in the analyses of the measurement error budget of these instruments is introduced here. The potential errors induced by the complex behaviour of contact between measuring probe tips and engineering surfaces are of concern in this study. These potential errors are usually neglected by researchers.
IOP Conference Series: Materials Science and Engineering, 2019
Scarf adhesive joints (SAJs) have attracted an increasing attention in joining/repairing of carbo... more Scarf adhesive joints (SAJs) have attracted an increasing attention in joining/repairing of carbon-fiber reinforced epoxy (CFRE) composite structures due to their zero eccentricity, which provides better aerodynamic surfaces. This study evaluated for the first time, the performance of SAJs in CFRE composites under thermo-mechanical impact loads. The adhesive was modified with optimum percentage of multi-walled carbon nanotubes (CNTs). The impact tests were performed at room temperature of +25°C, +50°C and +75°C. The residual flexural properties of the unfailed impacted joints were measured using three-point bending test. Results from impact tests at temperature of 25°C, 50°C and 75°C showed improvement in the impact bending stiffness of the modified SAJs with CNTs by 8.3%, 7.4% and 11.8% and maximum contact force by 15.6%, 21.3% and 18.9%, respectively. The energy at failure of the CNT-SAJs was increased by 15.2% and 16.4% respectively at temperatures of 25°C and 50°C. At test tempe...
Due to the influence of the manufacturing process on the composite’s wear properties, mathematica... more Due to the influence of the manufacturing process on the composite’s wear properties, mathematical models cannot accurately predict the wear rates and coefficients of friction of composite materials. As a result, this work provides a deeper comprehension of the tribological properties of Al-TiO2 nanocomposites with varying TiO2 content tested at varying sliding loads as well as improved predictability. Accumulative roll bonding (ARB) was used to create Al-TiO2 nanocomposites that had good TiO2 nanoparticle dispersion in the matrix. The pin-on-disc test was used to measure their wear rates and coefficient of friction. A neural network model was used to predict the wear rates and the coefficient of friction because there was a correlation between the composite morphology, hardness, and microstructure, as well as the evolution of the tribological properties. Due to the uniform distribution of TiO2 nanoparticles within the composite and the saturation of grain refinement in the Al matri...
In this paper, we present a newly modified machine learning model that employs a long short-term ... more In this paper, we present a newly modified machine learning model that employs a long short-term memory (LSTM) neural network model with the golden jackal optimization (GJO) algorithm to predict the tribological performance of Cu–Al2O3 nanocomposites. The modified model was applied to predict the wear rates and coefficient of friction of Cu–Al2O3 nanocomposites that were developed in this study. Electroless coating of Al2O3 nanoparticles with Ag was performed to improve the wettability followed by ball milling and compaction to consolidate the composites. The microstructural, mechanical, and wear properties of the produced composites with different Al2O3 content were characterized. The wear rates and coefficient of friction were evaluated using sliding wear tests at different loads and speeds. From a materials point of view, the manufactured composites with 10% Al2O3 content showed huge enhancement in hardness and wear rates compared to pure copper, reaching 170% and 65%, respective...
Wettability between Cu and Al 2 O 3 nanoparticles is relatively low, which limit the applicabilit... more Wettability between Cu and Al 2 O 3 nanoparticles is relatively low, which limit the applicability of this nanocomposite. To this end, electro-less deposition of Ag over Al 2 O 3 nanoparticles were applied to improve their wettability with Cu matrix. Al 2 O 3 coated Ag were mixed with commercially pure Cu powder in varying weight percentages (0, 2, 4, 6 and 8) and then nanocomposites were synthesized through powder metallurgy route. To obtain uniform distribution of nanoparticles in Cu matrix, mixing was carried out via mechanical alloying. Microstructure, mechanical and wear behaviors were investigated to see the effect of Al 2 O 3 nanoparticles content in Cu. The result showed that Al 2 O 3 nanoparticles are homogenously dispersed in the Cu matrix. The hardness and compressive strength were improved by the addition of nanoparticles up to 8 wt%. Around 30% improvement was found in the strength of the nanocomposite. Furthermore, the average hardness of the composite coatings varies from 65.2 to 150 HV as Al 2 O 3 content increases from 0 to 8 wt%. Abrasive wear analysis showed that the abrasive wear resistance of the nanocomposites improves with the increment of nanoparticle content. The microstructure refines due to Al 2 O 3 addendums illustrated a considerable function in the wear behavior of the Cu matrix.
Aluminum (Al) composites have been extensively developed for automotive applications due to their... more Aluminum (Al) composites have been extensively developed for automotive applications due to their high specific strength. Therefore, in this study, an Al-titanium dioxide (TiO2) nanocomposite was processed using the accumulative roll bonding (ARB) process. The mechanical characteristics of monolithic and nanocomposites specimens made with 0, 1, 2, and 3 wt% TiO2 nanoparticles as reinforcement were studied at several ARB passes. According to the microstructure of the composites, rolling after five passes achieves a homogenous distribution of reinforcement particles, ultrafine and elongated grains of the matrix. After five ARB passes, the TiO2 particles were uniformly dispersed. Finally, scanning electron microscopy and energy dispersive spectroscopy revealed that the Al-TiO2 nanocomposite had an appropriate dispersion of TiO2 nanoparticles. Vickers microhardness improves as the number of accumulative roll bonding passes increases. Furthermore, after five passes, Vickers microhardness...
This paper presents a machine learning model to predict the effect of Al2O3 nanoparticles content... more This paper presents a machine learning model to predict the effect of Al2O3 nanoparticles content on the wear rates in Cu-Al2O3 nanocomposite prepared using in situ chemical technique. The model developed is a modification of the random vector functional link (RVFL) algorithm using artificial hummingbird algorithm (AHA). The objective of using AHA is used to find the optimal configuration of RVFL to enhance the prediction of Al2O3 nanoparticles. The preparation of the composite was done using aluminum nitrate that was added to a solution containing scattered copper nitrate. After that, the powders of CuO and Al2O3 were obtained, and the leftover liquid was removed using a thermal treatment at 850 °C for 1 h. The powders were consolidated using compaction and sintering processes. The microhardness of the nanocomposite with 12.5% Al2O3 content is 2.03-fold times larger than the pure copper, while the wear rate of the same composite is reduced, reaching 55% lower than pure copper. Thes...
This paper presents a machine learning model to predict the effect of Al2O3 nanoparticle content ... more This paper presents a machine learning model to predict the effect of Al2O3 nanoparticle content on the coefficient of thermal expansion in Cu-Al2O3 nanocomposites prepared using an in situ chemical technique. The model developed is a modification of Long Short-Term Memory (LSTM) using dwarf mongoose optimization (DMO), which mimics the behavior of DMO to find its food for predicting the behavior of the composite. The swarm of DMO consists of three groups, namely the alpha group, scouts, and babysitters. Each group has its own behavior to capture the food. The preparation of the nanocomposite was performed using aluminum nitrate that was added to a solution containing scattered copper nitrate. After that, the powders of CuO and Al2O3 were obtained, and the leftover liquid was removed using thermal treatment at 850 °C for 1 h. The powders were consolidated using compaction and sintering processes. The impact of Al2O3 contents on the thermal properties of the Cu-Al2O3 nanocomposite wa...
This investigation explores the behaviour of contact interaction between probe tips of indicators... more This investigation explores the behaviour of contact interaction between probe tips of indicators (displacement gauges) and rough engineering surfaces, in order to gain new insights into uncertainty in industrial precision gauging. The conditions of interest are contact of a mm-scale hard sphere at 0.1 to 5 N force with metallic surfaces, Rq < 2 mm. The motivation arises from the growing demand of modern industries for higher machining processes and for finer inspection capabilities. In the near future, such a demand is likely to require careful analyses of the measurement error budget of these instruments with a greater consideration of the potential errors induced by the complex behaviour of contact, which is currently assumed to be negligible. A preliminary experimental study was carried out on an existing test-rig of limited accuracy. It raised several concerns related to the effects of surface roughness and material on the resulting contact deflection at the load regimes of ...
This manuscript aims to study the effects of drilling factors on the thermal-mechanical propertie... more This manuscript aims to study the effects of drilling factors on the thermal-mechanical properties and delamination experimentally during the drilling of glass fiber reinforced polymer (GFRP). Drilling studies were carried out using a CNC machine under dry cutting conditions by 6 mm diameter with different point angles of ∅ = 100°, 118°, and 140°. The drill spindle speed (400, 800, 1600 rpm), feed (0.025, 0.05, 0.1, 0.2 mm/r), and sample thickness (2.6, 5.3, and 7.7 mm) are considered in the analysis. Heat affected zone (HAZ) generated by drilling was measured using a thermal infrared camera and two K-thermocouples installed in the internal coolant holes of the drill. Therefore, two setups were used; the first is with a rotating drill and fixed specimen holder, and the second is with a rotating holder and fixed drill bit. To measure thrust force/torque through drilling, the Kistler dynamometer model 9272 was utilized. Pull-in and push-out delamination were evaluated based on the ima...
ABSTRACT Among the most important elements in aircraft structures are joints for transferring loa... more ABSTRACT Among the most important elements in aircraft structures are joints for transferring loads. An accurate assessment of the stresses for joints is essential for reliable strength evaluation and failure prediction. The aim of this work is to compare different types of materials, i. e. isotropic, laminated, and functionally graded materials (FGM), and different types of laminates, considering the ratio of stresses generated around a hole in a plate and the applied stress. The finite element method (FEM) is used to evaluate the stresses around a hole for the three types of materials when the plate is subjected to tensile stress, heating, and both heating and tensile stress. Utilizing the ANSYS package, the target of the study was to investigate the validity of the method. The results obtained for the laminated plate are compared to those obtained by E. Pan, and Rybiki &amp; Hopper for both (90/0)s and (–45/45)s laminates. By similar results, it was shown that the laminates can withstand loads better than isotropic materials or FGM.
Since the introduction of aseptic surgery by Lister towards the end of the eighteenth century, en... more Since the introduction of aseptic surgery by Lister towards the end of the eighteenth century, engineering materials have been implanted into the human body in many forms. Implant surgery has developed to the extent that implants are now used in most branches of surgery and are becoming increasingly more sophisticated. Orthopaedic surgery probably uses more implants than any other branch of medicine. Fracture fixation being one of the oldest and most common applications. This literature review tries to inclusively summarize the recent development in bio-medical materials and its applications in human joint implants up to year 2010.
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