Faculty Publications

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Author: search.filters.author.Joladarashi, S.Subject: search.filters.subject.Viscoelasticity

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    Rheological Properties of the In-house Prepared Magneto-rheological Fluid in the Pre-yield Region
    (Materials and Energy Research Center, 2022) Nagiredla, S.; Joladarashi, S.; Kumar, H.
    The essence of the present work is to study the rheological properties of the in-house prepared magnetorheological (MR) fluids in the pre-yield region since the rheological properties play a vital role in better understanding of vibration damping capabilities of MR fluids. In the present work, two different compositions of MR fluid samples were prepared with 24 and 30 volume percentages of carbonyl iron (CI) particles. Prepared MR fluid samples contain CI particles as a dispersive medium, silicone oil as a carrier fluid and white lithium grease as an anti-settling agent. The oscillating driving frequency and amplitude strain sweep tests are performed to investigate the rheological properties within the pre-yield region. The influences of driving frequency, strain amplitude, magnetic field and CI particles volume percentage on the rheological properties of the prepared MR fluids were assessed. The linear viscoelastic region of the prepared MR fluid sample was identified and the yield strain obtained was around 0.371%. It is observed that the volume percentage of CI particles in the MR fluid strongly influenced the rheological properties. © 2022 Materials and Energy Research Center. All rights reserved.
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    Bending and vibration studies of FG porous sandwich beam with viscoelastic boundary conditions: FE approach
    (Taylor and Francis Ltd., 2023) Patil, R.; Joladarashi, S.; Kadoli, R.
    Bending and vibration characteristics of FG porous sandwich beam with viscoelastic boundary conditions are investigated. Complex shear modulus and associated loss factor are considered for the viscoelastic interlayer. The beam is constrained by viscoelastic supports (VES) at either end. Complex stiffness model is adopted for VES. The transverse deflection, natural frequency, loss factors, and mode shapes are obtained by varying VES stiffness. Furthermore, the study is extended to sandwich beams with various (H, O, V, and X) porosity patterns. The results convey that VES contribution in vibration damping is more predominant when the supports are less stiff (more viscous). © 2022 Taylor & Francis Group, LLC.
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    Effect of porosity and viscoelastic boundary conditions on FG sandwich beams in thermal environment: Buckling and vibration studies
    (Elsevier Ltd, 2023) Patil, R.; Joladarashi, S.; Kadoli, R.
    The present study is carried out to investigate the combined effect of porosity and temperature on the buckling and vibration attributes of FG sandwich beams in the thermal environment using FE formulation. The modeled sandwich beam consisting of the viscoelastic core material is restrained by viscoelastic boundary conditions (VBCs). The FG face layers and core are subjected to temperature-dependent material properties. Complex stiffness model is adopted for VBCs. Porosity patterns such as H, V, X, and O are incorporated into FG face layers. The Lagrange equation is used to derive the sandwich beam's equilibrium equations of motion in static and dynamic conditions. The derived equilibrium equations are solved for buckling and vibration of the beam using the FE solution. Lagrange and Hermite shape functions are assumed for axial and transverse displacements. Critical buckling temperature (CBT), natural frequency (NF), and loss factors (LF) are obtained for various temperatures and boundary stiffness values (BSVs). Transverse buckling and vibration mode shapes are extracted for changing BSVs. The behavior of NF and LF at buckling temperature is also discussed. The existence of porosities ameliorates the buckling characteristics of the sandwich beam. VBCs expedite the vibration damping of sandwich beams alongside the viscoelastic core. The natural frequency and loss factor reach zero and infinity, respectively, when the temperature reaches CBT. © 2023 Institution of Structural Engineers
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    Modelling and predicting the dynamic response of an axially graded viscoelastic core sandwich beam
    (KeAi Communications Co., 2023) Nagiredla, S.; Joladarashi, S.; Kumar, H.
    The present study explored the influence of axial gradation of viscoelastic materials on the dynamic response of the sandwich beam for structural applications. The finite element (FE) formulations are used to model and investigate dynamic response of the sandwich beam. The classical beam theory is used to develop the FE formulations and Lagrange's approach is considered to obtain the equations of motion (EOM). FE code is developed and validated with the existing literature and also conducted the convergence study for the developed FE method. Further, the influence of different viscoelastic materials and boundary conditions on the dynamic response of the sandwich beam is investigated. Four different axial gradation configurations of viscoelastic materials are considered for the present work to explore the influence on natural frequency, loss factor and frequency response of the sandwich beam. The modeled axial gradation of viscoelastic material has displayed a considerable impact on the peak vibrational amplitude response of the sandwich beam for all the boundary conditions and these configurations improved the damping capabilities at different configurations for the structural applications. © 2023 China Ordnance Society