Rahul Cadambi - Academia.edu (original) (raw)

Papers by Rahul Cadambi

Volume 1: Compressors, Fans, and Pumps; Turbines; Heat Transfer; Structures and Dynamics, 2019

The planetary gearbox is often susceptible to faults under dynamic condition. Most of the literat... more The planetary gearbox is often susceptible to faults under dynamic condition. Most of the literature assumes that gearboxes are free from defects. But in real-time working condition these assumptions are not accurate. Therefore the challenge lies in identifying and localizing a fault in planetary gearbox under dynamic condition. In this paper, the focus is on modelling and simulation of a fault in a planetary gearbox and validate the same with experimental tests. A planetary gearbox is modelled as per DIN standard and simulated for time and frequency domain signals. On comparing a fault free and fault induced frequency domain signals, a small peaks are observed on either side of the mesh frequencies, indicating the presence of a fault in the planetary gearbox. These peaks around the mesh frequencies are used to localize the fault in a planetary gearbox. Simulation results are validated with the experimental test results of the planetary gearbox under dynamic conditions. Similar tren...

Materials Today: Proceedings, 2017

The increase in demand to reduce packaging cost has pushed industries to look for an alternate ma... more The increase in demand to reduce packaging cost has pushed industries to look for an alternate material for packaging. At present, only wooden pallets are used as it is low cost, versatile and easy to dispose. As a result of these many trees are cut down depleting our forest reserve and increasing global warming. In this paper an attempt has been made to design and analyze the use of rubber material for pallets. Concepts are drawn based on the customer requirement and ISO standard. The rubber material is tested for its properties. Appropriate material model for rubber is selected, modelled and analyzed for deflection. Based on the results, a concept is selected for reduced deflection and weight.

Materials Today: Proceedings, 2020

Vacuum infusion process is one of the Out-of-Autoclave (OoA) technologies which is emerging as on... more Vacuum infusion process is one of the Out-of-Autoclave (OoA) technologies which is emerging as one of the potential alternative for autoclave process in manufacturing structural components. Presently, vacuum infusion process (BMVIP) has a drawback of low Fiber Volume Fraction (FVF) and has more voids content. In this research work, BMVIP is modified by adding a double bag (DBVIP), by creating a resin trap (RTVIP) and by using a silicone bag (SBVIP). Laminates prepared from vacuum infusion processes is subjected to estimation of FVF and void content, mechanical tests and DMA studies. Modifications in vacuum infusion processes increased the FVF to 58.3%, reduced void content to 1.29% and increased tensile, flexural and ILSS properties by 25%, 12% and 12% respectively.

Materials Today: Proceedings, 2020

Drilling of composites are generally associated with fiber pull out and delamination. The aim of ... more Drilling of composites are generally associated with fiber pull out and delamination. The aim of this paper is to optimize the drilling process parameters and study the influence of twist drill bit geometry like point angle on delamination by FE analysis and experimental studies. Using DOE technique, different speeds and feed rates are used to carry out drilling of CFRP laminates experimentally and by ABAQUS. Delamination area of CFRP drilled hole from simulation and experimental results are analysed using Image J software. Speed of 3500 rpm and a feed rate of 0.1 mm/rev is found to be optimum value. Further, point angle in drill bit geometry is modified to 90 0 , 118 0 and 135 0 and effect of delamination is simulated and studied using ABAQUS.

MATEC Web of Conferences, 2018

Planetary gearbox is used in high precision applications such as robotic arm, control system of a... more Planetary gearbox is used in high precision applications such as robotic arm, control system of antenna, positioning and radar tracking systems. Planetary gearbox have high torque-to-weight ratio, high degree of control over the speed range and better efficiency. Most of the literatures assume that the gearbox are free from errors. Errors significantly affect the dynamic characteristics of the gearbox. The major challenge is to model these errors and study its behaviour under dynamic condition. The simulation results of time domain signal when converted to frequency domain signal, it shows the presence of error in the gearbox. Also, simulation result indicates a non-uniform motion of planetary gearbox in the presence of errors.

Materials Today: Proceedings, 2017

Molybdenum disulfide (MoS 2) nanoparticles have been successfully synthesized using Chemical Vapo... more Molybdenum disulfide (MoS 2) nanoparticles have been successfully synthesized using Chemical Vapour Deposition (CVD) technique. Inorganic precursors have been used to develop MoS 2 nanoparticles. A detailed study has been carried out to investigate the influence of process parameters on morphological structure of MoS 2 nanoparticles. The nanoparticles have been characterized by Scanning Electron Microscope (SEM) and Xray Diffraction (XRD) technique. Investigations revealed that the temperature plays an important role in obtaining desired morphology of MoS 2 nanostructures. Nanostructures of different morphologies like nanoparticles, nanorods and nanoplate have been synthesized at different temperatures. It was observed that nanopartciles of different morphologies can be synthesized at 800 °C itself using CVD technique. The dimensions of nanoparticles synthesized have been analyzed using SEM as well as Scherrer's equation using XRD results. The results of XRD and SEM are in close agreement with each other.

Materials Today: Proceedings, 2017

Drilling of glass fibre reinforced composites is difficult due to high structural stiffness and l... more Drilling of glass fibre reinforced composites is difficult due to high structural stiffness and low thermal conductivity of plastics. Laminate composites consisting of layers of plies are prone to delamination during drilling operation. Selection of appropriate drilling process parameters is very essential to reduce the damage in glass fibre reinforced composites. The effect of cutting parameters like speed and feed rate during drilling process for both experiment and numerical simulation has been studied and analysed in this work. Experimental and numerical simulation quantification of delamination effect induced by drilling is performed using Image J. The experimental results agree reasonably with numerical simulation.

Optimization of the Processing of HNBR∕Organoclay Nanocomposite. [AIP Conference Proceedings 1255... more Optimization of the Processing of HNBR∕Organoclay Nanocomposite. [AIP Conference Proceedings 1255, 138 (2010)]. Rahul M. Cadambi, Elaheh Ghassemieh. Abstract. In the current investigation, rubber∕clay nanocomposites ...

Plastics, Rubber and Composites, 2012

In this study, three different elastomers, namely hydrogenated nitrile butadiene rubber, fluoroel... more In this study, three different elastomers, namely hydrogenated nitrile butadiene rubber, fluoroelastomer and silicone, have been subjected to two different hard metallised coatings by ion implantation process. The three different elastomers are commonly used in various seal applications, where reduced wear and gas permeability are essential in maintaining seal performance and functionality. Samples of these rubbers have been coated with chromium coating in one set of tests. In the second set of tests, samples of elastomers have been coated with tungsten carbide coating being deposited on all the three different elastomers. Wear, gas permeability and mechanical behaviour of the coated samples were compared with each other and with the control uncoated elastomers. All the coated samples showed good reduction in gas permeability. With the use of metallised coatings, there has been improved resistance to wear in all the coated samples. Adhesion strength and effect of coating on the elastomer have been investigated by mechanical testing. Mechanical tests revealed good adhesion of metal coatings on all the rubber samples, and there was no detrimental effect on the mechanical properties after coating.

Plastics, Rubber and Composites, 2011

In this research, two different methods have been investigated for optimising the preparation of ... more In this research, two different methods have been investigated for optimising the preparation of hydrogenated acrylonitrile butadiene rubber/clay nanocomposites. Commercially available organoclay (Cloisite 20A) has been considered for the preparation of rubber nanocomposites. A detailed analysis has been made to investigate the morphological structure and mechanical behaviour at room temperature and at elevated temperature. Also the influence of organoclays on permeability has been studied. Structural analysis indicates very good dispersion for a low loading of 5 parts per hundred (phr) amount of nanoclays. Significant improvements in mechanical properties have been observed with the addition of organoclays at both room and elevated temperatures. Even with the low level of addition of nanoclays, there was a remarkable reduction in permeability.

Journal of Elastomers & Plastics, 2012

Hydrogenated nitrile butadiene rubber (HNBR) nanocomposites were prepared using commercially avai... more Hydrogenated nitrile butadiene rubber (HNBR) nanocomposites were prepared using commercially available organoclays (Cloisite 15A). The main focus of the current investigation is to study the influence of the organoclay reinforced in HNBR after subjecting it to long-term oxidative ageing and immersion studies. All the different nanoclay nanocomposites were air aged for a period of 168 h and at 150°C. The changes in the mechanical properties such as tensile strength and elongation at break have been compared with respect to the control sample. For immersion tests, three different liquid mediums were considered for this current investigation. All the samples were immersed in different mediums for a period of 168 h at 150°C. The changes in the swelling index and the mechanical properties have been reported with respect to the control sample. After reinforcing nanoclays into HNBR there was good resistance to swelling in all the three different liquid mediums in comparison to control samp...

Journal of Applied Polymer Science, 2011

The effects of addition of reinforcing carbon nanotubes (CNTs) into hydrogenated nitrile-butadien... more The effects of addition of reinforcing carbon nanotubes (CNTs) into hydrogenated nitrile-butadiene rubber (HNBR) matrix on the mechanical, dynamic viscoelastic, and permeability properties were studied in this investigation. Different techniques of incorporating nanotubes in HNBR were investigated in this research. The techniques considered were more suitable for industrial preparation of rubber composites. The nanotubes were modified with different surfactants and dispersion agents to improve the compatibility and adhesion of nanotubes on the HNBR matrix. The effects of the surface modification of the nanotubes on various properties were examined in detail. The amount of CNTs was varied from 2.5 to 10 phr in different formulations prepared to identify the optimum CNT levels. A detailed analysis was made to investigate the morphological structure and mechanical behavior at room temperature. The viscoelastic behavior of the nanotube filler elastomer was studied by dynamic mechanical thermal analysis (DMTA). Morphological analysis indicated a very good dispersion of the CNTs for a low nanotube loading of 3.5 phr. A significant improvement in the mechanical properties was observed with the addition of nanotubes. DMTA studies revealed an increase in the storage modulus and a reduction in the glass-transition temperature after the incorporation of the nanotubes. Further, the HNBR/CNT nanocomposites were subjected to permeability studies. The studies showed a significant reduction in the permeability of nitrogen gas. V

Advances in Polymer Technology, 2012

ABSTRACT The influence of the layered silicate clay platelets on the nitrogen permeation properti... more ABSTRACT The influence of the layered silicate clay platelets on the nitrogen permeation properties of hydrogenated nitrile butadiene rubber (HNBR)/nanoclay nanocomposites has been investigated. Nanocomposites of HNBR modified with different percentages of the organoclay are processed through various routes. Commercially available organoclay (CLOISITE 15A) and various silane-coupling agents are used to improve the dispersion of the nanoclay in HNBR. A total of 10 different formulations of nanocomposites are manufactured. The addition of the organoclay has resulted in a significant enhancement of the nitrogen barrier properties of the manufactured nanocomposite. The mechanism of the reduction in the permeability is explained through the changes in the morphology and its bond to the filler. These changes are confirmed through examination of the morphology using x-ray diffraction, transmission electron microscope, and dynamic mechanical thermal analysis. There has been a drastic reduction up to 55.7% in nitrogen permeability. The reduction in gas permeation in HNBR is attributed to uniformly exfoliated clay platelets. Finally, three different permeability models, namely, the Nielsen model, modified Nielsen model, and Cussler model, have also been considered to predict the permeability behavior of nanocomposites with different volume filler fractions. The experimental values of gas permeability have been compared with theoretical models. It is observed that the modified Nielsen model closely matches with the measured permeation behavior. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 32: E103–E118, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20275

Volume 1: Compressors, Fans, and Pumps; Turbines; Heat Transfer; Structures and Dynamics, 2019

The planetary gearbox is often susceptible to faults under dynamic condition. Most of the literat... more The planetary gearbox is often susceptible to faults under dynamic condition. Most of the literature assumes that gearboxes are free from defects. But in real-time working condition these assumptions are not accurate. Therefore the challenge lies in identifying and localizing a fault in planetary gearbox under dynamic condition. In this paper, the focus is on modelling and simulation of a fault in a planetary gearbox and validate the same with experimental tests. A planetary gearbox is modelled as per DIN standard and simulated for time and frequency domain signals. On comparing a fault free and fault induced frequency domain signals, a small peaks are observed on either side of the mesh frequencies, indicating the presence of a fault in the planetary gearbox. These peaks around the mesh frequencies are used to localize the fault in a planetary gearbox. Simulation results are validated with the experimental test results of the planetary gearbox under dynamic conditions. Similar tren...

Materials Today: Proceedings, 2017

The increase in demand to reduce packaging cost has pushed industries to look for an alternate ma... more The increase in demand to reduce packaging cost has pushed industries to look for an alternate material for packaging. At present, only wooden pallets are used as it is low cost, versatile and easy to dispose. As a result of these many trees are cut down depleting our forest reserve and increasing global warming. In this paper an attempt has been made to design and analyze the use of rubber material for pallets. Concepts are drawn based on the customer requirement and ISO standard. The rubber material is tested for its properties. Appropriate material model for rubber is selected, modelled and analyzed for deflection. Based on the results, a concept is selected for reduced deflection and weight.

Materials Today: Proceedings, 2020

Vacuum infusion process is one of the Out-of-Autoclave (OoA) technologies which is emerging as on... more Vacuum infusion process is one of the Out-of-Autoclave (OoA) technologies which is emerging as one of the potential alternative for autoclave process in manufacturing structural components. Presently, vacuum infusion process (BMVIP) has a drawback of low Fiber Volume Fraction (FVF) and has more voids content. In this research work, BMVIP is modified by adding a double bag (DBVIP), by creating a resin trap (RTVIP) and by using a silicone bag (SBVIP). Laminates prepared from vacuum infusion processes is subjected to estimation of FVF and void content, mechanical tests and DMA studies. Modifications in vacuum infusion processes increased the FVF to 58.3%, reduced void content to 1.29% and increased tensile, flexural and ILSS properties by 25%, 12% and 12% respectively.

Materials Today: Proceedings, 2020

Drilling of composites are generally associated with fiber pull out and delamination. The aim of ... more Drilling of composites are generally associated with fiber pull out and delamination. The aim of this paper is to optimize the drilling process parameters and study the influence of twist drill bit geometry like point angle on delamination by FE analysis and experimental studies. Using DOE technique, different speeds and feed rates are used to carry out drilling of CFRP laminates experimentally and by ABAQUS. Delamination area of CFRP drilled hole from simulation and experimental results are analysed using Image J software. Speed of 3500 rpm and a feed rate of 0.1 mm/rev is found to be optimum value. Further, point angle in drill bit geometry is modified to 90 0 , 118 0 and 135 0 and effect of delamination is simulated and studied using ABAQUS.

MATEC Web of Conferences, 2018

Planetary gearbox is used in high precision applications such as robotic arm, control system of a... more Planetary gearbox is used in high precision applications such as robotic arm, control system of antenna, positioning and radar tracking systems. Planetary gearbox have high torque-to-weight ratio, high degree of control over the speed range and better efficiency. Most of the literatures assume that the gearbox are free from errors. Errors significantly affect the dynamic characteristics of the gearbox. The major challenge is to model these errors and study its behaviour under dynamic condition. The simulation results of time domain signal when converted to frequency domain signal, it shows the presence of error in the gearbox. Also, simulation result indicates a non-uniform motion of planetary gearbox in the presence of errors.

Materials Today: Proceedings, 2017

Molybdenum disulfide (MoS 2) nanoparticles have been successfully synthesized using Chemical Vapo... more Molybdenum disulfide (MoS 2) nanoparticles have been successfully synthesized using Chemical Vapour Deposition (CVD) technique. Inorganic precursors have been used to develop MoS 2 nanoparticles. A detailed study has been carried out to investigate the influence of process parameters on morphological structure of MoS 2 nanoparticles. The nanoparticles have been characterized by Scanning Electron Microscope (SEM) and Xray Diffraction (XRD) technique. Investigations revealed that the temperature plays an important role in obtaining desired morphology of MoS 2 nanostructures. Nanostructures of different morphologies like nanoparticles, nanorods and nanoplate have been synthesized at different temperatures. It was observed that nanopartciles of different morphologies can be synthesized at 800 °C itself using CVD technique. The dimensions of nanoparticles synthesized have been analyzed using SEM as well as Scherrer's equation using XRD results. The results of XRD and SEM are in close agreement with each other.

Materials Today: Proceedings, 2017

Drilling of glass fibre reinforced composites is difficult due to high structural stiffness and l... more Drilling of glass fibre reinforced composites is difficult due to high structural stiffness and low thermal conductivity of plastics. Laminate composites consisting of layers of plies are prone to delamination during drilling operation. Selection of appropriate drilling process parameters is very essential to reduce the damage in glass fibre reinforced composites. The effect of cutting parameters like speed and feed rate during drilling process for both experiment and numerical simulation has been studied and analysed in this work. Experimental and numerical simulation quantification of delamination effect induced by drilling is performed using Image J. The experimental results agree reasonably with numerical simulation.

Optimization of the Processing of HNBR∕Organoclay Nanocomposite. [AIP Conference Proceedings 1255... more Optimization of the Processing of HNBR∕Organoclay Nanocomposite. [AIP Conference Proceedings 1255, 138 (2010)]. Rahul M. Cadambi, Elaheh Ghassemieh. Abstract. In the current investigation, rubber∕clay nanocomposites ...

Plastics, Rubber and Composites, 2012

In this study, three different elastomers, namely hydrogenated nitrile butadiene rubber, fluoroel... more In this study, three different elastomers, namely hydrogenated nitrile butadiene rubber, fluoroelastomer and silicone, have been subjected to two different hard metallised coatings by ion implantation process. The three different elastomers are commonly used in various seal applications, where reduced wear and gas permeability are essential in maintaining seal performance and functionality. Samples of these rubbers have been coated with chromium coating in one set of tests. In the second set of tests, samples of elastomers have been coated with tungsten carbide coating being deposited on all the three different elastomers. Wear, gas permeability and mechanical behaviour of the coated samples were compared with each other and with the control uncoated elastomers. All the coated samples showed good reduction in gas permeability. With the use of metallised coatings, there has been improved resistance to wear in all the coated samples. Adhesion strength and effect of coating on the elastomer have been investigated by mechanical testing. Mechanical tests revealed good adhesion of metal coatings on all the rubber samples, and there was no detrimental effect on the mechanical properties after coating.

Plastics, Rubber and Composites, 2011

In this research, two different methods have been investigated for optimising the preparation of ... more In this research, two different methods have been investigated for optimising the preparation of hydrogenated acrylonitrile butadiene rubber/clay nanocomposites. Commercially available organoclay (Cloisite 20A) has been considered for the preparation of rubber nanocomposites. A detailed analysis has been made to investigate the morphological structure and mechanical behaviour at room temperature and at elevated temperature. Also the influence of organoclays on permeability has been studied. Structural analysis indicates very good dispersion for a low loading of 5 parts per hundred (phr) amount of nanoclays. Significant improvements in mechanical properties have been observed with the addition of organoclays at both room and elevated temperatures. Even with the low level of addition of nanoclays, there was a remarkable reduction in permeability.

Journal of Elastomers & Plastics, 2012

Hydrogenated nitrile butadiene rubber (HNBR) nanocomposites were prepared using commercially avai... more Hydrogenated nitrile butadiene rubber (HNBR) nanocomposites were prepared using commercially available organoclays (Cloisite 15A). The main focus of the current investigation is to study the influence of the organoclay reinforced in HNBR after subjecting it to long-term oxidative ageing and immersion studies. All the different nanoclay nanocomposites were air aged for a period of 168 h and at 150°C. The changes in the mechanical properties such as tensile strength and elongation at break have been compared with respect to the control sample. For immersion tests, three different liquid mediums were considered for this current investigation. All the samples were immersed in different mediums for a period of 168 h at 150°C. The changes in the swelling index and the mechanical properties have been reported with respect to the control sample. After reinforcing nanoclays into HNBR there was good resistance to swelling in all the three different liquid mediums in comparison to control samp...

Journal of Applied Polymer Science, 2011

The effects of addition of reinforcing carbon nanotubes (CNTs) into hydrogenated nitrile-butadien... more The effects of addition of reinforcing carbon nanotubes (CNTs) into hydrogenated nitrile-butadiene rubber (HNBR) matrix on the mechanical, dynamic viscoelastic, and permeability properties were studied in this investigation. Different techniques of incorporating nanotubes in HNBR were investigated in this research. The techniques considered were more suitable for industrial preparation of rubber composites. The nanotubes were modified with different surfactants and dispersion agents to improve the compatibility and adhesion of nanotubes on the HNBR matrix. The effects of the surface modification of the nanotubes on various properties were examined in detail. The amount of CNTs was varied from 2.5 to 10 phr in different formulations prepared to identify the optimum CNT levels. A detailed analysis was made to investigate the morphological structure and mechanical behavior at room temperature. The viscoelastic behavior of the nanotube filler elastomer was studied by dynamic mechanical thermal analysis (DMTA). Morphological analysis indicated a very good dispersion of the CNTs for a low nanotube loading of 3.5 phr. A significant improvement in the mechanical properties was observed with the addition of nanotubes. DMTA studies revealed an increase in the storage modulus and a reduction in the glass-transition temperature after the incorporation of the nanotubes. Further, the HNBR/CNT nanocomposites were subjected to permeability studies. The studies showed a significant reduction in the permeability of nitrogen gas. V

Advances in Polymer Technology, 2012

ABSTRACT The influence of the layered silicate clay platelets on the nitrogen permeation properti... more ABSTRACT The influence of the layered silicate clay platelets on the nitrogen permeation properties of hydrogenated nitrile butadiene rubber (HNBR)/nanoclay nanocomposites has been investigated. Nanocomposites of HNBR modified with different percentages of the organoclay are processed through various routes. Commercially available organoclay (CLOISITE 15A) and various silane-coupling agents are used to improve the dispersion of the nanoclay in HNBR. A total of 10 different formulations of nanocomposites are manufactured. The addition of the organoclay has resulted in a significant enhancement of the nitrogen barrier properties of the manufactured nanocomposite. The mechanism of the reduction in the permeability is explained through the changes in the morphology and its bond to the filler. These changes are confirmed through examination of the morphology using x-ray diffraction, transmission electron microscope, and dynamic mechanical thermal analysis. There has been a drastic reduction up to 55.7% in nitrogen permeability. The reduction in gas permeation in HNBR is attributed to uniformly exfoliated clay platelets. Finally, three different permeability models, namely, the Nielsen model, modified Nielsen model, and Cussler model, have also been considered to predict the permeability behavior of nanocomposites with different volume filler fractions. The experimental values of gas permeability have been compared with theoretical models. It is observed that the modified Nielsen model closely matches with the measured permeation behavior. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 32: E103–E118, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20275