Browsing by Author "Gonsalves, T.H."

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Dynamic characterization of hybrid composite material of rotor-bearing support system
(Taylor and Francis Ltd., 2022) Gonsalves, T.H.; Garje Channabasappa, M.K.; Motagondanahalli Rangarasaiah, R.; Joladarashi, S.
In this paper, the dynamic characterization of hybrid composite material of carbon-epoxy sandwiched by steel is presented from the rotor-bearing system perspective. The tensile and flexural strengths of the hybrid material are investigated followed by the detailed damping estimation using modal testing in cantilever mode and dynamic mechanical analysis in double cantilever mode. The experimental characterization results obtained in this work have fundamentally ascertained the mechanical and dynamic behavior of hybrid composite material for the intended application. © 2020 Taylor & Francis Group, LLC.
Dynamic study of composite material shaft in high-speed rotor-bearing systems
(Inderscience Publishers, 2019) Gonsalves, T.H.; Kumar, G.C.; Ramesh, M.R.
In this work the composite material shaft in high-speed rotor-bearing systems is analysed to achieve better rotor dynamics along with the effect of internal damping of the composite shaft. The pioneering studies on rotating composite shaft and internal damping are revisited to evaluate its effects on rotor dynamics of high-speed rotor-bearing systems. Two practical rotor-bearing systems are selected to study their suitability for composite shaft application where the composite material is used in the cold section while the existing steel alloy is retained in the hot section as well as at the ends. The rotor dynamic analysis shows significant improvements in rotor dynamics of one of the rotor-bearing systems where the first lateral mode changes to desirable rigid mode from flexure mode shape of existing metallic shaft rotor-bearing system. The frequency values of second and third modes also increase above the operating speed indicating a clear advantage in rotor dynamics. © © 2019 Inderscience Enterprises Ltd.
Hybrid composite shaft of High-Speed Rotor-Bearing System - A rotor dynamics preview
(Bellwether Publishing, Ltd., 2021) Gonsalves, T.H.; Garje Channabasappa, M.K.; Motagondanahalli Rangarasaiah, R.
In this present study, the detailed rotor dynamic evaluation of hybrid composite material rotating shaft of a power turbine high-speed rotor-bearing system is presented. The slender power turbine shaft of front driving turboshaft engine powering the rotorcraft requires a stiffer and lighter material to exhibit better rotor dynamics. Based on the preliminary investigation which predicted substantial rotor dynamic advantages, the laminated composite material shaft is proposed in the compressor section of the rotor-bearing system. To avoid the direct exposure of composite material to the harsh environment of gas turbine engine, hybrid metal fiber form of rotating shaft is employed. The hybrid metal fiber shaft is comprised of a core laminated carbon-epoxy tube sandwiched by steel tubes both inside and outside. The effect of parametric variation in the laminate and length of the hybrid shaft is evaluated and compared with the existing steel shaft. The viscoelastic material damping of carbon-epoxy laminate is also included as a rotating internal damping to evaluate the rotor dynamic instability threshold of the rotor-bearing system. From the analysis, it is found that the combination of metal and fiber-reinforced material can effectively leverage the combined strengths of both materials. © 2020 Taylor & Francis Group, LLC.
Leveraging the effectiveness of hybrid metal-fiber composites in high speed rotating machines
(2019) Gonsalves, T.H.; Mohankumar, G.C.; Ramesh, M.R.
Fiber metal composites made up of alternative layers of metallic and composite are now widely used in Aircraft structures are result of one such effort which bring in the combined strengths of composites and metals. In a similar way, the use of metal fiber composites made up of composite material laminates sandwiched between metallic sheets firmly bonded with high quality adhesives can become an effective replacement of conventional metallic components in high speed machinery such as gas turbines. The benefits of this hybrid form of composite material has the potential of use in areas where fiber reinforced composite material cannot be directly exposed due to the harsh environment of gas turbines. In addition, the metallic surfaces can easily interface into their respective metallic assemblies. Such hybrid composite materials used in static structures can push some of the structural natural frequencies beyond the operating speeds. Composite material used in supporting structures can effectively dampen the excessive vibrations and to further improve the damping capacity the viscoelastic material can also be strategically inserted between the layers. In rotating systems hybrid composite material can be used for some of the long slender shafts to push the critical speeds away from the operating speeds. But unlike supporting structures the damping present in the composite material can induce rotor dynamic instability of rotor-bearing systems. Hence the right combination of metal and fiber reinforced composites can effectively avoid or place the resonances and drastically reduce the vibrating stresses to improve the overall fatigue life of rotating machinery. � 2018 Author(s).
Leveraging the effectiveness of hybrid metal-fiber composites in high speed rotating machines
(American Institute of Physics Inc. subs@aip.org, 2019) Gonsalves, T.H.; Mohan Kumar, G.C.; Ramesh, M.R.
Fiber metal composites made up of alternative layers of metallic and composite are now widely used in Aircraft structures are result of one such effort which bring in the combined strengths of composites and metals. In a similar way, the use of metal fiber composites made up of composite material laminates sandwiched between metallic sheets firmly bonded with high quality adhesives can become an effective replacement of conventional metallic components in high speed machinery such as gas turbines. The benefits of this hybrid form of composite material has the potential of use in areas where fiber reinforced composite material cannot be directly exposed due to the harsh environment of gas turbines. In addition, the metallic surfaces can easily interface into their respective metallic assemblies. Such hybrid composite materials used in static structures can push some of the structural natural frequencies beyond the operating speeds. Composite material used in supporting structures can effectively dampen the excessive vibrations and to further improve the damping capacity the viscoelastic material can also be strategically inserted between the layers. In rotating systems hybrid composite material can be used for some of the long slender shafts to push the critical speeds away from the operating speeds. But unlike supporting structures the damping present in the composite material can induce rotor dynamic instability of rotor-bearing systems. Hence the right combination of metal and fiber reinforced composites can effectively avoid or place the resonances and drastically reduce the vibrating stresses to improve the overall fatigue life of rotating machinery. Â© 2018 Author(s).
Model updating of material damping in composite material of rotor-bearing support system
(American Institute of Physics Inc. subs@aip.org, 2020) Gonsalves, T.H.; Kumar, G.C.M.; Ramesh, M.R.
In this paper the finite element model updating technique is evaluated for the estimation and modeling of material damping of composite material intended to be used in a high-speed rotor-bearing support system. An accurate estimation and modeling of material damping is required for the proper understanding of the dynamic behavior of composite material used in the high-speed rotor-bearing system. Due to the contrasting relevance of material damping as rotating internal damping and stationary external support damping in a high-speed rotor-bearing system, updating methodology is required to be varied. Hence to start with, the finite element numerical model updating of stationary damping of composite material is presented here using the test data extracted from the experimental free vibration and dynamic mechanical analysis (DMA) tests. Â© 2020 Author(s).
Parametric study of laminated composite material shaft of high speed rotor-bearing system
(2018) Gonsalves, T.H.; Mohankumar, G.C.; Ramesh, M.R.
In this paper some of the important parameters that influence the effectiveness of composite material shaft of high speed rotor-bearing system on rotor dynamics are analyzed. The type of composite material composition, the number of layers along with their stacking sequences are evaluated as they play an important role in deciding the best configuration suitable for the high-speed application. In this work the lateral modal frequencies for five types of composite materials shaft of a high-speed power turbine rotor-bearing system and stresses due to operating torque are evaluated. The results are useful for the selection of right combination of material, number of layers and their stacking sequences. The numerical analysis is carried out using the ANSYS Rotor dynamic analysis features. � 2018 Author(s).
Parametric study of laminated composite material shaft of high speed rotor-bearing system
(American Institute of Physics Inc. subs@aip.org, 2018) Gonsalves, T.H.; Mohan Kumar, G.C.; Ramesh, M.R.
In this paper some of the important parameters that influence the effectiveness of composite material shaft of high speed rotor-bearing system on rotor dynamics are analyzed. The type of composite material composition, the number of layers along with their stacking sequences are evaluated as they play an important role in deciding the best configuration suitable for the high-speed application. In this work the lateral modal frequencies for five types of composite materials shaft of a high-speed power turbine rotor-bearing system and stresses due to operating torque are evaluated. The results are useful for the selection of right combination of material, number of layers and their stacking sequences. The numerical analysis is carried out using the ANSYS Rotor dynamic analysis features. Â© 2018 Author(s).