basavraj kothavale - Academia.edu (original) (raw)

Papers by basavraj kothavale

SIMULATION

This article provides an overview of the smooth particle hydrodynamics (SPH) approach and its mat... more This article provides an overview of the smooth particle hydrodynamics (SPH) approach and its mathematical modeling. SPH is a numerical technique based on a mesh-free Lagrangian scheme for evaluating the continuum mechanics problems. This method is suitable in the case of continuum objects undergoing large deformation, as conventional finite element methods are unreliable due to mesh failure and convergence issues. It is a widely used approach in the field of astrophysics, fluid mechanics, structural mechanics, soil mechanics, automobiles, and so on. A numerical example is also considered in this research paper to demonstrate the applicability of the method. The simulation process was achieved using LS-Dyna explicit solver software, and plots related to cutting and thrust forces, von Mises stress, plastic strain, temperature distribution, and so on, were obtained. Also, the effect of Time-Scaling Factor (TSSFAC) on SPH simulations was observed in this research.

Materials Today: Proceedings

World Academy of Science, Engineering and Technology, International Journal of Economics and Management Engineering, 2016

An estimation of the spur gear service life and crack path analysisis proposed in this paper. I p... more An estimation of the spur gear service life and crack path analysisis proposed in this paper. I p theory using numerical solution is used to find the fatigue crack propagation rate, service life, and crack path due to bending fatigue. A spur gear of tumbler gear mechanism of lathe machine,is implemented for this analysis. An experimental test on gear specimens was carried out to analyze the crack propagation due to fatigue. Besides, service life estimated by the theory was compared with the most common Paris law. Hence further,extended finite element approach (Ansys)is implemented for the simulation of gear crack propagation trajectory. The simulation results are verified with experimental test.The service life and crack trajectory of the gear is obtained with 'Ip' theory and found in good agreement with experiment.In overall, this study signifies the gear failure prediction methodology during crack propagationin respect of life cycles and trajectory path.

Volume 8B: Heat Transfer and Thermal Engineering, 2018

Natural Convection heat transfer from horizontal rectangular fin array with various knurling patt... more Natural Convection heat transfer from horizontal rectangular fin array with various knurling patterns is studied experimentally to find the effect of varying surface roughness on the heat transfer rate. The experimental parametric study is performed to investigate the effect of knurl produced surface roughness of fin on heat transfer rate. The parameters like knurling height from base, knurling depth and fin spacing might affect the flow characteristics and hence it is investigated to find the effect on heat transfer coefficient. The knurling is usually accomplished using one or more very hard rollers that contain the reverse of the pattern to be imposed. The result of this study shows that there are some important geometric factors related to knurling affecting the design of fin arrays and also heat transfer augmentation of natural convection heat transfer is observed.

International Review of Mechanical Engineering (IREME), 2018

Bending fatigue is one of the failure modes of spur gear tooth. Crack initiates at the root of a ... more Bending fatigue is one of the failure modes of spur gear tooth. Crack initiates at the root of a tooth on the active side. Crack due to bending fatigue results in tooth breakage. It may cause a sudden or catastrophic failure of spur gears. A major concern for design engineers is to prevent this type of failure, because it will cause accidents, casualties and financial losses. Many researchers have done excellent work on crack propagation in gears due to bending fatigue. Different crack growth models, based on the linear elastic fracture mechanics (LEFM), are used for crack propagation analysis and prediction of the service life of gears. The study in this paper includes the factorial design approach used for gear tooth bending fatigue crack propagation for specific gear configurations. Experiments are performed on the gears with optimized parameters for three different materials. Crack propagation life is estimated for these gears materials. Finite element (with Mechanical APDL 17.0) analysis for crack propagation is also done on optimized gear with SAE8620 materials.

International Review of Mechanical Engineering-IREME, 2018

The present paper summarizes the review of numerical and experimental works done by researchers t... more The present paper summarizes the review of numerical and experimental works done by researchers to study various types of fin configurations under natural convection conditions to increase heat transfer with different fin surface roughness. Compared to plane fin, the fin with varying surface roughness influence heat transfer in varying degrees. Fins with perforations of rectangular, circular, triangular shape etc. and fins with extensions or protrusions of various shapes have been studied. Such perforations / protrusions induce flow discontinuity over fins and hence help to alter flow quantities near the wall. Thus generated instability in boundary layer increase heat transfer from fins. In some studies, it was found that roughness height plays an important role and is a decisive factor in increasing or decreasing heat transfer from such surfaces. In other studies, roughness patterns considerably enhance heat transfer from 10 to 40 % compared to plane fin. As a future scope, fins w...

CNC turning center is one of the significant CNC-assisted machine tools, widely used for differen... more CNC turning center is one of the significant CNC-assisted machine tools, widely used for different machining operations. The quality, reliability and maintainability of such CNC turning centers are critical for both the manufacturers and users. In this context, it is decided to carry out failure modes and effects analysis (FMEA) of a typical CNC turning center manufactured and used in India. A FMEA framework is proposed for the analysis of the CNC turning center. The main objective of analysis was to identify critical failure modes and their effects on the components and sub-systems. This study uses the field failure data from more than 50 CNC turning centers and opinions from more than five industrial experts. CNCS, EES, XZAS, ChS, MT, HS, CS and SS are found to be the critical sub-systems of the CNC turning center.CNCS, HS, MT, EES, ChS, TS, XZAS and CS are the critical sub-systems from reliability and maintainability perspective.

Engine cooling fans are an essential component of the engine cooling system which is used to diss... more Engine cooling fans are an essential component of the engine cooling system which is used to dissipate the excess heat generated by the combustion of fuels inside the engine. This project consists of designing the fan and analyzing it for its strength in structure using the Finite Element Method (FEM) approach and the flow of air around it using Computational Fluid Dynamics (CFD) approach. An important factor for successful fan design is to fully understand the complex flow field within the fan. This understanding enables optimization. Computational Fluid Dynamics (CFD) techniques can be beneficial to provide insight to the fan design process. Not only can velocity vectors and pressure contours be computed, CFD can also provide critical information such as efficiency, flow uniformity at the exit, circulation or separation zones, locations of potential cavitations and noise generation. The design of the fan was conducted in phases, starting with calculating all the required dimension...

Tube bending is a widely used manufacturing process in the aerospace, automotive, and various oth... more Tube bending is a widely used manufacturing process in the aerospace, automotive, and various other industries. Cold bending of metal tubes is very important production method considering that metal tubes are widely used in a great variety of engineering products, such as automobile, aircraft, air conditioner, air compressor, exhaust systems, fluid lines. During tube bending, considerable in-plane distortion and thickness variation occurs. This paper deals with the study of Rotary Draw Tube Bending process and the Finite Element Analysis and Simulation of Rotary Draw Tube Bending of a seamless metal tube for the analysis of spring back effect. Mathematical and Experimental analysis of spring back are carried out and results are compared. By applying the theory on pure beam bending deformation, the mathematical model of spring back for pipe bending deformation is established. The Simpson's rule is applied for solving the radius in spring back. The paper also covers the modeling o...

Reliability, Safety and Hazard Assessment for Risk-Based Technologies, 2019

Human and Organizational Factors (HOFs) play an important role in the safe, reliable, and maintai... more Human and Organizational Factors (HOFs) play an important role in the safe, reliable, and maintainable operation of the CNC turning center (CNCTC). Several human performance influencing factors (PIFs) and organizational factors (OFs) influence the human reliability. In this paper, some human PIFs and OFs which may affect the human reliability during maintenance phase are defined and considered for the prioritization according to their criticality using the expert judgments. It is observed that experience is the most important human performance influencing factor (PIF) and safety culture is the most critical organizational factor (OF) affecting the human reliability. The time-between-failure (TBF) and time-to-repair (TTR) data significantly influenced by HOFs are analyzed using the techniques of reliability and maintainability, and the results of the analysis are compared with those of the TBF and TTR data which are not significantly affected by HOFs. The field failure and repair data were sorted considering the influence of hardware, software, and HOFs using expert judgments and outcomes of reliability and maintainability analysis. It has been observed that 16.33% of the total failures and 15.49% of total repairs are significantly influenced by HOFs. Nearly 66% of the total failures and repairs are due to hardware system. The reliability and maintainability of the CNCTC are greatly influenced by HOFs. The HOFs can reduce the expected life of the components or sub-systems of the CNCTC by 33%.

Heat Transfer-Asian Research, 2019

Natural convection heat transfer from horizontal rectangular fin array with various knurling patt... more Natural convection heat transfer from horizontal rectangular fin array with various knurling patterns has been studied experimentally by the present authors to investigate the effect of knurl-produced surface roughness of fin on the heat transfer rate. The parameters like knurling height from base, knurling depth, fin spacing, and supply wattage were considered for parametric study. In the present paper, numerical method (CFD) is used to simulate natural convection phenomena with knurled fins and results are validated with the experimental data available from literature. The numerical results show similar trends compared with experimental data and one can use this method to study various fin configurations for knurling patterns. The flow patterns from experiments and numerical method are compared for different supply wattages and fin spacing to back up the conclusion. It is also observed that the variation in nondimensional roughness depth and spacing (D kn /H and S/H) have more effect on Nusselt number than roughness height parameter (H kn /H). Further, the method is extended to study numerically large number of fin configurations with knurling patterns to gather sufficient data for Nusselt number with respect to fin

SSRN Electronic Journal, 2018

In high speed applications like pumps, turbines, turbocharger journal bearing serviceability is v... more In high speed applications like pumps, turbines, turbocharger journal bearing serviceability is very important one. The journal bearing acting as a support for high rotary speeds as well as acting as a damping element so as to absorb the vibrations at high speeds. In hydrodynamic region if failure of lubrication or starved lubrication is occurred it responsible for tremendous amount of friction between the shaft and bearing with high wear loss causing damage to the surfaces of the component. So it focuses that use of sintered composites for journal bearing applications is suitable for reduced frictional wear. However experimental analysis is required for sintered composites at high speed with starved or dry conditions of lubrication. The combine effect of parameters has to be studied for tribological behaviour of sintered journal bearings. It includes surface quality, alloying material compositions, porosity of sintered bearings, geometrical aspects and external conditions like applied loads, speed transitions, temperature, lubricating conditions etc. With reference to said subject thorough literature review was carried out. It provides very valuable information regarding parametric analysis and its effect on friction and wear of bearings in different situations of temperature, load, speeds etc

International Review of Mechanical Engineering (IREME), 2018

The intensity growth of manufacturing industry in India is increasing the demand of CNC turning c... more The intensity growth of manufacturing industry in India is increasing the demand of CNC turning centers. The producers of CNC turning centers are trying to fulfil this demand. The quality and reliability of such CNC turning centers is critical for manufacturers and users to meet the market demand. In this context, it is required to identify the potential failures and minimize their occurrence probability. Failure modes and effects analysis (FMEA) is a robust methodology used to study the risk and reliability of various systems. In this paper, FMEA methodology is used to analyze the risk involved in the operation of CNC turning centers. The objective of the analysis was to identify critical failure modes, components and sub-systems. The study uses field failure data from more than 50 CNC turning centers and more than five industrial experts. FMEA results are further compared to the failure rates obtained from the field failure data. The results of the FMEA analysis are useful for system reliability improvement and optimizing maintenance. Electrical and electronic components have higher failure rates compared to mechanical components. CNCS, MT, XZAS, HS, ChS and SS are found to be critical sub-systems.

SSRN Electronic Journal, 2018

Today, the CNC turning center becomes an important machine tool for manufacturing industry worldw... more Today, the CNC turning center becomes an important machine tool for manufacturing industry worldwide. However, as the breakdown of a single CNC turning center may result in the production of an entire plant being halted. For this reason, operations and preventive maintenance have to be minimized to ensure availability of the system. Indeed, improving the availability of the CNC turning center as a whole, objectively leads to a substantial reduction in production loss, operating, maintenance and support cost. In this paper, fault tree analysis (FTA) method is used for reliability analysis of CNC turning center. The major faults associated with the system and the causes for the faults are presented graphically. Boolean algebra is used for evaluating fault tree (FT) diagram and for deriving governing reliability model for CNC turning center. Failure data over a period of six years has been collected and used for evaluating the model. Qualitative and quantitative analysis is also carried out to identify critical subsystems and components of CNC turning center. It is found that, at the end of warranty period (one year), the reliability of the CNC turning center as a whole is around 0.61628.

Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability, 2018

This article provides a generalized framework for selection of time-to-failure model based on the... more This article provides a generalized framework for selection of time-to-failure model based on the assessment of trends in failure and repair time data. This framework is based on modifications of existing frameworks and can be applied for binary as well as multi-state systems. The proposed framework is applied for reliability analysis of a computerized numerical control turning center. For analysis purpose, the failure data are collected for 50 computerized numerical control turning center over a period of 7 years for three different working conditions, that is, when machining material is steel, aluminum and cast iron. The data collected are then processed using the proposed framework and the best-fit distribution is found for the time-to-failure data. Furthermore, the reliable life and reliabilities of the different sub-systems are estimated. From the analysis, it is found that spindle system, computerized numerical control system, electrical and electronic system, hydraulic system...

International Journal of Quality & Reliability Management, 2017

Purpose The paper presents reliability, maintainability and life cycle cost (LCC) analysis of a c... more Purpose The paper presents reliability, maintainability and life cycle cost (LCC) analysis of a computerized numerical control (CNC) turning center which is manufactured and used in India. The purpose of this paper is to identify the critical components/subsystems from reliability and LCC perspective. The paper further aims at improving reliability and LCC by implementing reliability-improvement methods. Design/methodology/approach This paper uses a methodology for the reliability analysis based on the assessment of trends in maintenance data. The data required for reliability and LCC analysis are collected from the manufacturers and users of CNC turning center over a period of eight years. ReliaSoft’s Weibull++9 software has been used for verifying goodness of fit and estimating parameters of the distribution. The LCC of the system is estimated for five cost elements: acquisition cost, operation cost, failure cost, support cost and net salvage value. Findings The analysis shows tha...

AIP Advances, 2016

Dielectric and energy storage performances of PVDF-based composites with colossal permittivitied ... more Dielectric and energy storage performances of PVDF-based composites with colossal permittivitied Nd-doped BaTiO 3 nanoparticles as the filler

SIMULATION

This article provides an overview of the smooth particle hydrodynamics (SPH) approach and its mat... more This article provides an overview of the smooth particle hydrodynamics (SPH) approach and its mathematical modeling. SPH is a numerical technique based on a mesh-free Lagrangian scheme for evaluating the continuum mechanics problems. This method is suitable in the case of continuum objects undergoing large deformation, as conventional finite element methods are unreliable due to mesh failure and convergence issues. It is a widely used approach in the field of astrophysics, fluid mechanics, structural mechanics, soil mechanics, automobiles, and so on. A numerical example is also considered in this research paper to demonstrate the applicability of the method. The simulation process was achieved using LS-Dyna explicit solver software, and plots related to cutting and thrust forces, von Mises stress, plastic strain, temperature distribution, and so on, were obtained. Also, the effect of Time-Scaling Factor (TSSFAC) on SPH simulations was observed in this research.

Materials Today: Proceedings

World Academy of Science, Engineering and Technology, International Journal of Economics and Management Engineering, 2016

An estimation of the spur gear service life and crack path analysisis proposed in this paper. I p... more An estimation of the spur gear service life and crack path analysisis proposed in this paper. I p theory using numerical solution is used to find the fatigue crack propagation rate, service life, and crack path due to bending fatigue. A spur gear of tumbler gear mechanism of lathe machine,is implemented for this analysis. An experimental test on gear specimens was carried out to analyze the crack propagation due to fatigue. Besides, service life estimated by the theory was compared with the most common Paris law. Hence further,extended finite element approach (Ansys)is implemented for the simulation of gear crack propagation trajectory. The simulation results are verified with experimental test.The service life and crack trajectory of the gear is obtained with 'Ip' theory and found in good agreement with experiment.In overall, this study signifies the gear failure prediction methodology during crack propagationin respect of life cycles and trajectory path.

Volume 8B: Heat Transfer and Thermal Engineering, 2018

Natural Convection heat transfer from horizontal rectangular fin array with various knurling patt... more Natural Convection heat transfer from horizontal rectangular fin array with various knurling patterns is studied experimentally to find the effect of varying surface roughness on the heat transfer rate. The experimental parametric study is performed to investigate the effect of knurl produced surface roughness of fin on heat transfer rate. The parameters like knurling height from base, knurling depth and fin spacing might affect the flow characteristics and hence it is investigated to find the effect on heat transfer coefficient. The knurling is usually accomplished using one or more very hard rollers that contain the reverse of the pattern to be imposed. The result of this study shows that there are some important geometric factors related to knurling affecting the design of fin arrays and also heat transfer augmentation of natural convection heat transfer is observed.

International Review of Mechanical Engineering (IREME), 2018

Bending fatigue is one of the failure modes of spur gear tooth. Crack initiates at the root of a ... more Bending fatigue is one of the failure modes of spur gear tooth. Crack initiates at the root of a tooth on the active side. Crack due to bending fatigue results in tooth breakage. It may cause a sudden or catastrophic failure of spur gears. A major concern for design engineers is to prevent this type of failure, because it will cause accidents, casualties and financial losses. Many researchers have done excellent work on crack propagation in gears due to bending fatigue. Different crack growth models, based on the linear elastic fracture mechanics (LEFM), are used for crack propagation analysis and prediction of the service life of gears. The study in this paper includes the factorial design approach used for gear tooth bending fatigue crack propagation for specific gear configurations. Experiments are performed on the gears with optimized parameters for three different materials. Crack propagation life is estimated for these gears materials. Finite element (with Mechanical APDL 17.0) analysis for crack propagation is also done on optimized gear with SAE8620 materials.

International Review of Mechanical Engineering-IREME, 2018

The present paper summarizes the review of numerical and experimental works done by researchers t... more The present paper summarizes the review of numerical and experimental works done by researchers to study various types of fin configurations under natural convection conditions to increase heat transfer with different fin surface roughness. Compared to plane fin, the fin with varying surface roughness influence heat transfer in varying degrees. Fins with perforations of rectangular, circular, triangular shape etc. and fins with extensions or protrusions of various shapes have been studied. Such perforations / protrusions induce flow discontinuity over fins and hence help to alter flow quantities near the wall. Thus generated instability in boundary layer increase heat transfer from fins. In some studies, it was found that roughness height plays an important role and is a decisive factor in increasing or decreasing heat transfer from such surfaces. In other studies, roughness patterns considerably enhance heat transfer from 10 to 40 % compared to plane fin. As a future scope, fins w...

CNC turning center is one of the significant CNC-assisted machine tools, widely used for differen... more CNC turning center is one of the significant CNC-assisted machine tools, widely used for different machining operations. The quality, reliability and maintainability of such CNC turning centers are critical for both the manufacturers and users. In this context, it is decided to carry out failure modes and effects analysis (FMEA) of a typical CNC turning center manufactured and used in India. A FMEA framework is proposed for the analysis of the CNC turning center. The main objective of analysis was to identify critical failure modes and their effects on the components and sub-systems. This study uses the field failure data from more than 50 CNC turning centers and opinions from more than five industrial experts. CNCS, EES, XZAS, ChS, MT, HS, CS and SS are found to be the critical sub-systems of the CNC turning center.CNCS, HS, MT, EES, ChS, TS, XZAS and CS are the critical sub-systems from reliability and maintainability perspective.

Engine cooling fans are an essential component of the engine cooling system which is used to diss... more Engine cooling fans are an essential component of the engine cooling system which is used to dissipate the excess heat generated by the combustion of fuels inside the engine. This project consists of designing the fan and analyzing it for its strength in structure using the Finite Element Method (FEM) approach and the flow of air around it using Computational Fluid Dynamics (CFD) approach. An important factor for successful fan design is to fully understand the complex flow field within the fan. This understanding enables optimization. Computational Fluid Dynamics (CFD) techniques can be beneficial to provide insight to the fan design process. Not only can velocity vectors and pressure contours be computed, CFD can also provide critical information such as efficiency, flow uniformity at the exit, circulation or separation zones, locations of potential cavitations and noise generation. The design of the fan was conducted in phases, starting with calculating all the required dimension...

Tube bending is a widely used manufacturing process in the aerospace, automotive, and various oth... more Tube bending is a widely used manufacturing process in the aerospace, automotive, and various other industries. Cold bending of metal tubes is very important production method considering that metal tubes are widely used in a great variety of engineering products, such as automobile, aircraft, air conditioner, air compressor, exhaust systems, fluid lines. During tube bending, considerable in-plane distortion and thickness variation occurs. This paper deals with the study of Rotary Draw Tube Bending process and the Finite Element Analysis and Simulation of Rotary Draw Tube Bending of a seamless metal tube for the analysis of spring back effect. Mathematical and Experimental analysis of spring back are carried out and results are compared. By applying the theory on pure beam bending deformation, the mathematical model of spring back for pipe bending deformation is established. The Simpson's rule is applied for solving the radius in spring back. The paper also covers the modeling o...

Reliability, Safety and Hazard Assessment for Risk-Based Technologies, 2019

Human and Organizational Factors (HOFs) play an important role in the safe, reliable, and maintai... more Human and Organizational Factors (HOFs) play an important role in the safe, reliable, and maintainable operation of the CNC turning center (CNCTC). Several human performance influencing factors (PIFs) and organizational factors (OFs) influence the human reliability. In this paper, some human PIFs and OFs which may affect the human reliability during maintenance phase are defined and considered for the prioritization according to their criticality using the expert judgments. It is observed that experience is the most important human performance influencing factor (PIF) and safety culture is the most critical organizational factor (OF) affecting the human reliability. The time-between-failure (TBF) and time-to-repair (TTR) data significantly influenced by HOFs are analyzed using the techniques of reliability and maintainability, and the results of the analysis are compared with those of the TBF and TTR data which are not significantly affected by HOFs. The field failure and repair data were sorted considering the influence of hardware, software, and HOFs using expert judgments and outcomes of reliability and maintainability analysis. It has been observed that 16.33% of the total failures and 15.49% of total repairs are significantly influenced by HOFs. Nearly 66% of the total failures and repairs are due to hardware system. The reliability and maintainability of the CNCTC are greatly influenced by HOFs. The HOFs can reduce the expected life of the components or sub-systems of the CNCTC by 33%.

Heat Transfer-Asian Research, 2019

Natural convection heat transfer from horizontal rectangular fin array with various knurling patt... more Natural convection heat transfer from horizontal rectangular fin array with various knurling patterns has been studied experimentally by the present authors to investigate the effect of knurl-produced surface roughness of fin on the heat transfer rate. The parameters like knurling height from base, knurling depth, fin spacing, and supply wattage were considered for parametric study. In the present paper, numerical method (CFD) is used to simulate natural convection phenomena with knurled fins and results are validated with the experimental data available from literature. The numerical results show similar trends compared with experimental data and one can use this method to study various fin configurations for knurling patterns. The flow patterns from experiments and numerical method are compared for different supply wattages and fin spacing to back up the conclusion. It is also observed that the variation in nondimensional roughness depth and spacing (D kn /H and S/H) have more effect on Nusselt number than roughness height parameter (H kn /H). Further, the method is extended to study numerically large number of fin configurations with knurling patterns to gather sufficient data for Nusselt number with respect to fin

SSRN Electronic Journal, 2018

In high speed applications like pumps, turbines, turbocharger journal bearing serviceability is v... more In high speed applications like pumps, turbines, turbocharger journal bearing serviceability is very important one. The journal bearing acting as a support for high rotary speeds as well as acting as a damping element so as to absorb the vibrations at high speeds. In hydrodynamic region if failure of lubrication or starved lubrication is occurred it responsible for tremendous amount of friction between the shaft and bearing with high wear loss causing damage to the surfaces of the component. So it focuses that use of sintered composites for journal bearing applications is suitable for reduced frictional wear. However experimental analysis is required for sintered composites at high speed with starved or dry conditions of lubrication. The combine effect of parameters has to be studied for tribological behaviour of sintered journal bearings. It includes surface quality, alloying material compositions, porosity of sintered bearings, geometrical aspects and external conditions like applied loads, speed transitions, temperature, lubricating conditions etc. With reference to said subject thorough literature review was carried out. It provides very valuable information regarding parametric analysis and its effect on friction and wear of bearings in different situations of temperature, load, speeds etc

International Review of Mechanical Engineering (IREME), 2018

The intensity growth of manufacturing industry in India is increasing the demand of CNC turning c... more The intensity growth of manufacturing industry in India is increasing the demand of CNC turning centers. The producers of CNC turning centers are trying to fulfil this demand. The quality and reliability of such CNC turning centers is critical for manufacturers and users to meet the market demand. In this context, it is required to identify the potential failures and minimize their occurrence probability. Failure modes and effects analysis (FMEA) is a robust methodology used to study the risk and reliability of various systems. In this paper, FMEA methodology is used to analyze the risk involved in the operation of CNC turning centers. The objective of the analysis was to identify critical failure modes, components and sub-systems. The study uses field failure data from more than 50 CNC turning centers and more than five industrial experts. FMEA results are further compared to the failure rates obtained from the field failure data. The results of the FMEA analysis are useful for system reliability improvement and optimizing maintenance. Electrical and electronic components have higher failure rates compared to mechanical components. CNCS, MT, XZAS, HS, ChS and SS are found to be critical sub-systems.

SSRN Electronic Journal, 2018

Today, the CNC turning center becomes an important machine tool for manufacturing industry worldw... more Today, the CNC turning center becomes an important machine tool for manufacturing industry worldwide. However, as the breakdown of a single CNC turning center may result in the production of an entire plant being halted. For this reason, operations and preventive maintenance have to be minimized to ensure availability of the system. Indeed, improving the availability of the CNC turning center as a whole, objectively leads to a substantial reduction in production loss, operating, maintenance and support cost. In this paper, fault tree analysis (FTA) method is used for reliability analysis of CNC turning center. The major faults associated with the system and the causes for the faults are presented graphically. Boolean algebra is used for evaluating fault tree (FT) diagram and for deriving governing reliability model for CNC turning center. Failure data over a period of six years has been collected and used for evaluating the model. Qualitative and quantitative analysis is also carried out to identify critical subsystems and components of CNC turning center. It is found that, at the end of warranty period (one year), the reliability of the CNC turning center as a whole is around 0.61628.

Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability, 2018

This article provides a generalized framework for selection of time-to-failure model based on the... more This article provides a generalized framework for selection of time-to-failure model based on the assessment of trends in failure and repair time data. This framework is based on modifications of existing frameworks and can be applied for binary as well as multi-state systems. The proposed framework is applied for reliability analysis of a computerized numerical control turning center. For analysis purpose, the failure data are collected for 50 computerized numerical control turning center over a period of 7 years for three different working conditions, that is, when machining material is steel, aluminum and cast iron. The data collected are then processed using the proposed framework and the best-fit distribution is found for the time-to-failure data. Furthermore, the reliable life and reliabilities of the different sub-systems are estimated. From the analysis, it is found that spindle system, computerized numerical control system, electrical and electronic system, hydraulic system...

International Journal of Quality & Reliability Management, 2017

Purpose The paper presents reliability, maintainability and life cycle cost (LCC) analysis of a c... more Purpose The paper presents reliability, maintainability and life cycle cost (LCC) analysis of a computerized numerical control (CNC) turning center which is manufactured and used in India. The purpose of this paper is to identify the critical components/subsystems from reliability and LCC perspective. The paper further aims at improving reliability and LCC by implementing reliability-improvement methods. Design/methodology/approach This paper uses a methodology for the reliability analysis based on the assessment of trends in maintenance data. The data required for reliability and LCC analysis are collected from the manufacturers and users of CNC turning center over a period of eight years. ReliaSoft’s Weibull++9 software has been used for verifying goodness of fit and estimating parameters of the distribution. The LCC of the system is estimated for five cost elements: acquisition cost, operation cost, failure cost, support cost and net salvage value. Findings The analysis shows tha...

AIP Advances, 2016

Dielectric and energy storage performances of PVDF-based composites with colossal permittivitied ... more Dielectric and energy storage performances of PVDF-based composites with colossal permittivitied Nd-doped BaTiO 3 nanoparticles as the filler