The current study investigates the behavior of wire electric discharge machining （WEDM） of the super alloy Udimet-L605 by employing sophisticated machine learning approaches. The experimental work was designed on th...The current study investigates the behavior of wire electric discharge machining （WEDM） of the super alloy Udimet-L605 by employing sophisticated machine learning approaches. The experimental work was designed on the basis of the Taguchi orthogonal L27 array, consid- ering six explanatory variables and evaluating their influ- ences on the cutting speed, wire wear ratio （WWR）, and dimensional deviation （DD）. A support vector machine （SVM） algorithm using a normalized poly-kernel and a radial-basis flow kernel is recommended for modeling the wire electric discharge machining process. The grey rela- tional analysis （GRA） approach was utilized to obtain the optimal combination of process variables simultaneously, providing the desirable outcome for the cutting speed, WWR, and DD. Scanning electron microscope and energy dispersive X-ray analyses of the samples were performed for the confirmation of the results. An SVM based on the radial-basis kernel model dominated the normalized poly- kernel model. The optimal combination of process vari- ables for a mutually desirable outcome for the cutting speed, WWR, and DD was determined as Ton1, Toffa, Ip1, WT3, SV1, and WF3. The pulse-on time is the significant variable influencing the cutting speed, WWR, and DD. The largest percentage of copper （8.66%） was observed at the highest cutting speed setting 7.05% of copper at the low of the machine compared to cutting speed setting of the machine.展开更多
Friction and wear behavior of AZ91D and its nanocomposites reinforced by different contents of hybrid multi-walled CNTs and nano-SiC particulates under oil lubrication was investigated using a MRS-10P four-ball tribom...Friction and wear behavior of AZ91D and its nanocomposites reinforced by different contents of hybrid multi-walled CNTs and nano-SiC particulates under oil lubrication was investigated using a MRS-10P four-ball tribometer.Friction coefficients and wear rates were measured within a load range of 200-1000 N at a spindle rotary speed of 380 r/min.Worn surface morphologies,phase and element compositions were studied by scanning electron microscope(SEM),X-ray diffraction(XRD)and energy dispersive spectroscopy(EDS),respectively.The mechanism of synergistic effect of CNTs and SiC nanoparticles was discussed.The results indicate that the AZ91D nanocomposites show better wear resistance properties and different wear mechanisms compared with AZ91D.The AZ91D nanocomposites reinforced with 0.5%CNTs and 0.5%nano-SiC have the best tribological capacity.The wear mechanisms for the Mg-based hybrid nanocomposites appear to be a mix-up of micro-ploughing,micro-cutting,slight adhesive wear and delamination.展开更多
Aiming at the issue of sliding ratio,an internal gear pair is proposed which consists of an involute internal gear and a pinion with quadratic curve teeth.Particularly,the contact pattern is point contact and the pini...Aiming at the issue of sliding ratio,an internal gear pair is proposed which consists of an involute internal gear and a pinion with quadratic curve teeth.Particularly,the contact pattern is point contact and the pinion is generated based on an involute gear.The generation method and mathematical models of the gear pair are presented.The sliding ratio is calculated and the general calculation formulas of sliding ratios are developed.Also,the comparison between the involute gear and proposed gear is made.The adaptability of center distance and contact stress are also discussed.In addition,the gear pair was manufactured and inspected according to the exactitude solid model of the gear pair.In order to confirm this model to be effective,the efficiency experiment and the contrast experiment with the involute gear pair were performed.Furthermore,these two types of pinions were analyzed by scanning electron microscope and wear depths were measured by measuring center.The experiment results show that the efficiency of the internal gear pair is stable at a range about 97.1%to 98.6%and wear depth is less than 50%of the involute gear pair.The internal gear pair is expected to have excellent transmission performance.展开更多
Zinc-aluminum alloys have been used as bearing materials in the past. In recent years, binary Al-Zn alloys and Al-Zn-Cu alloys are being used as an alternative to the Zn-Al alloys for bearing applications. In this stu...Zinc-aluminum alloys have been used as bearing materials in the past. In recent years, binary Al-Zn alloys and Al-Zn-Cu alloys are being used as an alternative to the Zn-Al alloys for bearing applications. In this study, both binary Al-25 Zn and Al-3 Cu were prepared using stir casting process. Homogenization of the as-cast alloys was performed at 350oC for 8 h and then, the alloys were furnace-cooled to 50oC. The homogenization led to the removal of the dendritic structure of the as-cast alloys. After homogenization, wear parameters optimization was carried out using Taguchi technique. For this purpose, L9 orthogonal array was selected, and the control parameters selected are load, velocity, and sliding distance. The optimum parametric condition was obtained using signal-to-noise(S/N) ratio analysis, and specific wear rate(SWR) is the selected response. The "smaller-the-better" is the goal of the experiment for S/N ratio analysis. After the optimization, confirmation tests were carried out using analysis of variance(ANOVA) from the developed regression equation. Finally, wear mechanism studies were conducted using scanning electron microscopy(SEM) and energy-dispersive X-ray spectroscopy(EDX) images.展开更多
Hybrid metal matrix composites (Hmmc) are found to be more superior than the conventional composite materials because of their improved mechanical properties, which can be suited for an extensive range of engineering ...Hybrid metal matrix composites (Hmmc) are found to be more superior than the conventional composite materials because of their improved mechanical properties, which can be suited for an extensive range of engineering applications. Automobile and aerospace industries widely make use of hybrid composites as they possess excellent corrosion, wear resistance, low density, and high strength. This paper displays the strategy to build the hybrid composite utilizing Stir casting Method. Present investigation includes the creation of composites utilizing boron carbide (2%, 4%, 6% volume) and Red mud (2% volume) as the reinforcements and Structural aluminium as the matrix. Experimental investigation of wear analysis of the composites was carried out according to the L9 Taguchi method. The designated number of experiments was accomplished to probe the impact of control factors on the specific wear rate (SWR) of the developed composites. ANOVA was carried out and Wt%. Reinforcement was found to be the decisive factor on the SWR of the developed hybrid composite. The Confirmatory test was successfully carried out and the computed error was found to be varying from 0.878% to 2.58%.展开更多
Tool wear is frequently considered in the modern CNC (computer numerical control) turning industry. Most existing optimization researches for CNC finish turning were either accomplished within certain manufacturing ci...Tool wear is frequently considered in the modern CNC (computer numerical control) turning industry. Most existing optimization researches for CNC finish turning were either accomplished within certain manufacturing circumstances, or achieved through numerous equipment operations. Therefore, a general deduction optimization scheme proposed is deemed to be necessary for the industry. In this paper, four parameters (cutting depth, feed rate, speed, tool nose runoff) with three levels (low, medium, high) are considered to optimize the tool wear for finish turning based on orthogonal array. Additionally, nine fuzzy control rules using triangle membership function with respective to five linguistic grades for tool wear are constructed. Considering four input and twenty output intervals, the defuzzification using center of gravity is then completed and introduced as the S/N (signal-to-noise) ratio. Thus, the optimum general deduction parameters can then be received. The confirmation experiment for optimum general deduction parameters is furthermore performed on an ECOCA-3807 CNC lathe. It is shown that the tool wear ratio from the fuzzy deduction optimization parameters is significantly advanced comparing to those from benchmark. This paper not only proposes a general deduction optimization scheme using orthogonal array, but also contributes the satisfactory fuzzy linguistic approach to tool wear in CNC turning with profound insight.展开更多
Applying a novel method of arc-glow plasma depositing, a 2μm-thick coating with 12 sub-layers of TiN and CrN was deposited alternately on the surface of magnesium alloy AZ91D to improve its wear resistance. The wear ...Applying a novel method of arc-glow plasma depositing, a 2μm-thick coating with 12 sub-layers of TiN and CrN was deposited alternately on the surface of magnesium alloy AZ91D to improve its wear resistance. The wear behavior was investigated by test of ball on disc sliding. The composition and microstructure of the coating were also analyzed by means of X-ray diffraction (XRD) and glow discharge spectrum (GDS), and the morphology of TiN-CrN film was surveyed through scanning electronic microscopy (SEM) and atom force microscopy (AFM).The adhesion strength between film and matrix was evaluated by ways of stick-peeling test. The surface micro-hardness of the coating is above HK0.011 433, and the specific wear ratio of specimens coated with TiN-CrN films tested decreases greatly compared to that of the bare metal.展开更多
文摘The current study investigates the behavior of wire electric discharge machining （WEDM） of the super alloy Udimet-L605 by employing sophisticated machine learning approaches. The experimental work was designed on the basis of the Taguchi orthogonal L27 array, consid- ering six explanatory variables and evaluating their influ- ences on the cutting speed, wire wear ratio （WWR）, and dimensional deviation （DD）. A support vector machine （SVM） algorithm using a normalized poly-kernel and a radial-basis flow kernel is recommended for modeling the wire electric discharge machining process. The grey rela- tional analysis （GRA） approach was utilized to obtain the optimal combination of process variables simultaneously, providing the desirable outcome for the cutting speed, WWR, and DD. Scanning electron microscope and energy dispersive X-ray analyses of the samples were performed for the confirmation of the results. An SVM based on the radial-basis kernel model dominated the normalized poly- kernel model. The optimal combination of process vari- ables for a mutually desirable outcome for the cutting speed, WWR, and DD was determined as Ton1, Toffa, Ip1, WT3, SV1, and WF3. The pulse-on time is the significant variable influencing the cutting speed, WWR, and DD. The largest percentage of copper （8.66%） was observed at the highest cutting speed setting 7.05% of copper at the low of the machine compared to cutting speed setting of the machine.
基金Projects(11272072,11672055)supported by the National Natural Science Foundation of China
文摘Friction and wear behavior of AZ91D and its nanocomposites reinforced by different contents of hybrid multi-walled CNTs and nano-SiC particulates under oil lubrication was investigated using a MRS-10P four-ball tribometer.Friction coefficients and wear rates were measured within a load range of 200-1000 N at a spindle rotary speed of 380 r/min.Worn surface morphologies,phase and element compositions were studied by scanning electron microscope(SEM),X-ray diffraction(XRD)and energy dispersive spectroscopy(EDS),respectively.The mechanism of synergistic effect of CNTs and SiC nanoparticles was discussed.The results indicate that the AZ91D nanocomposites show better wear resistance properties and different wear mechanisms compared with AZ91D.The AZ91D nanocomposites reinforced with 0.5%CNTs and 0.5%nano-SiC have the best tribological capacity.The wear mechanisms for the Mg-based hybrid nanocomposites appear to be a mix-up of micro-ploughing,micro-cutting,slight adhesive wear and delamination.
基金Project(51575062)supported by the National Natural Science Foundation of ChinaProject(SM2014D202)supported by the Fund of Shanghai Key Laboratory of Spacecraft Mechanism,China
文摘Aiming at the issue of sliding ratio,an internal gear pair is proposed which consists of an involute internal gear and a pinion with quadratic curve teeth.Particularly,the contact pattern is point contact and the pinion is generated based on an involute gear.The generation method and mathematical models of the gear pair are presented.The sliding ratio is calculated and the general calculation formulas of sliding ratios are developed.Also,the comparison between the involute gear and proposed gear is made.The adaptability of center distance and contact stress are also discussed.In addition,the gear pair was manufactured and inspected according to the exactitude solid model of the gear pair.In order to confirm this model to be effective,the efficiency experiment and the contrast experiment with the involute gear pair were performed.Furthermore,these two types of pinions were analyzed by scanning electron microscope and wear depths were measured by measuring center.The experiment results show that the efficiency of the internal gear pair is stable at a range about 97.1%to 98.6%and wear depth is less than 50%of the involute gear pair.The internal gear pair is expected to have excellent transmission performance.
文摘Zinc-aluminum alloys have been used as bearing materials in the past. In recent years, binary Al-Zn alloys and Al-Zn-Cu alloys are being used as an alternative to the Zn-Al alloys for bearing applications. In this study, both binary Al-25 Zn and Al-3 Cu were prepared using stir casting process. Homogenization of the as-cast alloys was performed at 350oC for 8 h and then, the alloys were furnace-cooled to 50oC. The homogenization led to the removal of the dendritic structure of the as-cast alloys. After homogenization, wear parameters optimization was carried out using Taguchi technique. For this purpose, L9 orthogonal array was selected, and the control parameters selected are load, velocity, and sliding distance. The optimum parametric condition was obtained using signal-to-noise(S/N) ratio analysis, and specific wear rate(SWR) is the selected response. The "smaller-the-better" is the goal of the experiment for S/N ratio analysis. After the optimization, confirmation tests were carried out using analysis of variance(ANOVA) from the developed regression equation. Finally, wear mechanism studies were conducted using scanning electron microscopy(SEM) and energy-dispersive X-ray spectroscopy(EDX) images.
文摘Hybrid metal matrix composites (Hmmc) are found to be more superior than the conventional composite materials because of their improved mechanical properties, which can be suited for an extensive range of engineering applications. Automobile and aerospace industries widely make use of hybrid composites as they possess excellent corrosion, wear resistance, low density, and high strength. This paper displays the strategy to build the hybrid composite utilizing Stir casting Method. Present investigation includes the creation of composites utilizing boron carbide (2%, 4%, 6% volume) and Red mud (2% volume) as the reinforcements and Structural aluminium as the matrix. Experimental investigation of wear analysis of the composites was carried out according to the L9 Taguchi method. The designated number of experiments was accomplished to probe the impact of control factors on the specific wear rate (SWR) of the developed composites. ANOVA was carried out and Wt%. Reinforcement was found to be the decisive factor on the SWR of the developed hybrid composite. The Confirmatory test was successfully carried out and the computed error was found to be varying from 0.878% to 2.58%.
文摘Tool wear is frequently considered in the modern CNC (computer numerical control) turning industry. Most existing optimization researches for CNC finish turning were either accomplished within certain manufacturing circumstances, or achieved through numerous equipment operations. Therefore, a general deduction optimization scheme proposed is deemed to be necessary for the industry. In this paper, four parameters (cutting depth, feed rate, speed, tool nose runoff) with three levels (low, medium, high) are considered to optimize the tool wear for finish turning based on orthogonal array. Additionally, nine fuzzy control rules using triangle membership function with respective to five linguistic grades for tool wear are constructed. Considering four input and twenty output intervals, the defuzzification using center of gravity is then completed and introduced as the S/N (signal-to-noise) ratio. Thus, the optimum general deduction parameters can then be received. The confirmation experiment for optimum general deduction parameters is furthermore performed on an ECOCA-3807 CNC lathe. It is shown that the tool wear ratio from the fuzzy deduction optimization parameters is significantly advanced comparing to those from benchmark. This paper not only proposes a general deduction optimization scheme using orthogonal array, but also contributes the satisfactory fuzzy linguistic approach to tool wear in CNC turning with profound insight.
基金Project(20041065) supported by the Natural Science Foundation of Shanxi Province, China
文摘Applying a novel method of arc-glow plasma depositing, a 2μm-thick coating with 12 sub-layers of TiN and CrN was deposited alternately on the surface of magnesium alloy AZ91D to improve its wear resistance. The wear behavior was investigated by test of ball on disc sliding. The composition and microstructure of the coating were also analyzed by means of X-ray diffraction (XRD) and glow discharge spectrum (GDS), and the morphology of TiN-CrN film was surveyed through scanning electronic microscopy (SEM) and atom force microscopy (AFM).The adhesion strength between film and matrix was evaluated by ways of stick-peeling test. The surface micro-hardness of the coating is above HK0.011 433, and the specific wear ratio of specimens coated with TiN-CrN films tested decreases greatly compared to that of the bare metal.
