BITS Faculty Publications

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Subject: search.filters.subject.Finite element analysis

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    Investigation on circular and octagonal concrete-filled double skinned steel tubular short columns under axial compression
    (Techno-Press, 2022-07) Kumar, Manoj
    This paper describes the experimental and numerical investigation on circular and octagonal CFDST short columns under concentric loading to study their responses to various internal circular steel tube sizes by the constant cross-sectional dimensions of the external circular and octagonal steel tube. The non-linear finite element analysis of circular and octagonal CFDST columns was executed using the ABAQUS to forecast and compare the axial behavior influenced by the various sizes of internal circular steel tubes. The study shows that the axial compressive strength and ductility of circular and octagonal CFDST columns were significantly influenced by inner steel tubes with the strengths of constituent materials.
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    Fluid-structure Interactions and Flow Induced Vibrations: A Review
    (Elsevier, 2016) Parameshwaran, R.
    Fluid-structure interaction (FSI) is intensely coupled with the flow induced vibration (FIV) through the motions induced on a deformable or moving structure being subjected to an external or internal fluid flow. This kind of interaction in turn evolves with a variety of flow phenomena having applications that ranges from aeroelasticity to blood flow through arteries. The prime objective of this paper is to review the potential research studies pertaining to a variety of modelling and computational techniques, dedicated for exploring the underlying physics of the phenomena relating to the fluid structure interactions and the flow induced vibrations. Technical revelations related to the dynamic effects of the flow induced vibrations on engineering systems in fluidic environment have been gleaned from numerous research studies and presented. Emphasis is also given on the fluid flow analysis pertaining to the excitation of low-frequency vibration modes in structures at nanoscale for the efficient design of modern engineering systems.
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    Endurance Life Estimation of Aircraft Compact Heat Exchanger
    (Journal of Aerospace Sciences and Technologies, 2012) Ranganayakulu, Chennu
    Heat Exchangers are used in various engineering systems to transfer heat from a hot fluid to cold fluid across an impermeable wall. The necessity of increased heat transfer surface area has resulted in the development of Compact Heat Exchangers (CHE). Due to their compactness, high performances and less weight, CHE is used for aerospace applications. CHE used in combat aircrafts experience arduous and extreme working conditions during their operation. Before its integration with aircraft, CHEs are required to be tested for performance and qualified for airworthiness by evaluating its endurance life. This paper provides the details of the facility established to experimentally evaluate the endurance life. A computational analysis was carried out to estimate the endurance life with respect to fatigue effects using Finite Element Analysis to calculate stress distribution due to pressure and temperature in CHE during maximum and minimum operating conditions. This was then utilized to calculate fatigue life of CHE. The results were compared with experimental data and it is understood that fatigue alone does not determine the endurance life and there are other parameters that significantly influence the life of CHE.
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    Fundamentals of Finite Element and Finite Volume Methods
    (ASME, 2018) Ranganayakulu, Chennu
    There are three distinct methods of numerical solution techniques: finite difference, finite volume and finite element methods. The purpose in each is to convert the differential equations into algebraic equations. The main differences between the three methods are associated with the way the differential equations are converted to algebraic equations.
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    Critical analysis of micro-thermogravimetry of CuSO4·5H2O crystals using heatable microcantilevers
    (IOP, 2019) Rao, V. Ramgopal
    Micro/nano thermogravimetry (TG) employing MEMS has significant potential to improve the minimum sample mass and mass resolution as compared to commercial TG instruments. Although there have been a few previous reports on MEMS TG, none of them have critically analysed the obtained TG curve in detail. In this work, we have designed and fabricated a microelectromechanical thermogravimetric device (MMTG) with integrated microheaters and temperature sensors. The mass sensitivity of the device was estimated to be 0.89 pg Hz−1 which outperforms the standard TG approaches. We tested the MMTG performance with CuSO4·5H2O crystals. The final mass loss ratio corresponds to the theoretically expected value, although the obtained TG curve deviated from the standard TG curve of CuSO4·5H2O obtained from commercial TG instruments. We attributed the deviation to the inherent temperature non-uniformity, non-isothermal conditions and temperature gradients of metallicwire based microheaters. Finite element (FE) simulations were carried out in order to confirm and gain insights into the non-uniform heating phenomena of microheater and sample. Based on the simulation results, we propose designs that can be realized to make MEMS TG a successful enterprise.
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    Analysis of a hybrid ultrasonic horn profile using finite element analysis
    (Elsevier, 2021) Kala, Prateek
    Ultrasonic machining is among the non-conventional machining technique which is used to machine very hard and brittle material with help of abrasives. The ultrasonic horn is the most important part of USM which amplifies the vibration available at the transducer end to attain a required amplification factor. In the present research paper, an attempt has been made to develop a new variant of ultrasonic horn which could result in maximum magnification factor with minimum induced stresses. A comparative analysis has been made among eight different horn shapes using Modal & Harmonic Analysis in commercially available finite element package i.e. ANSYS and a new design profile i.e. a hybrid horn has been presented to attain maximum amplification factor with a reduction in the equivalent stresses.
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    Thermal analysis of TIG-WAAM based metal deposition process using finite element method
    (Elsevier, 2021) Kala, Prateek
    The Tungsten Inert gas welding-based wire and arc additive manufacturing (TIG-WAAM) process is one of the most energy-efficient processes among the direct energy deposition processes. The TIG-WAAM process involves layer by layer deposition of a material using wire and arc. The path planning in the metal deposition process affects the temperature distribution during the layer by layer deposition in wire arc additive manufacturing (WAAM) process. The distribution of the temperature affects the quality of the metal deposition and its dimensional accuracy. In this paper, a Finite element analysis (FEA) based model for TIG-WAAM process was developed for analyzing the effect of the temperature distribution on the metal deposition process. The developed model has been used for simulating metal deposition using TIG-WAAM process for a single layer of low carbon steel. The distribution of temperature across the deposited material has been recorded. The results showed that the concentration of the temperature takes place at all turning points in the deposition path which may lead to deteriorating the quality of deposition. The developed model can be used further for the development of the feedback-based temperature management system to provide smooth metal deposition with better quality.
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    Prediction of residual stresses in biaxial stretching of tailor welded blanks by finite element analysis
    (IOP, 2019) Kumar, Amit
    Residual stresses in sheet metal components play an important role in determining the life of parts especially in automotive industry. In this work, residual stresses have been predicted numerically in biaxial stretching of laser welded interstitial free (IF) steel blanks of different thickness combinations. The effective stress-effective strain curves of the parent sheets obtained from uniaxial tensile tests have been used as an input in finite element (FE) simulations to define the flow behavior of the materials. It has been found out that the residual stresses are tensile and similar on both sides of the weld zone in tailor welded blanks (TWB) of same thickness combination. In TWBs of different thickness combinations, the residual stresses on both sides are tensile and almost equal in the central region of the cup and they became compressive as the distance from the pole increases. The effect of thickness ratio on residual stresses has also been predicted in FE simulations of biaxial stretching of TWBs. It has been found out that with increase in the thickness ratio, the residual stress has slightly increased. Residual stresses have also been determined experimentally by using x-ray diffraction technique and it has been found out that the predicted values agreed well with the experimental results.
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    The effect of ultrasonic vibrations on residual stresses and material properties of steel tubes during the cold tube drawing process
    (Taylor & Francis, 2022-09) Bera, T.C.
    In this study, the ultrasonically assisted plug vibrating tube drawing system was developed for an industrial draw bench and investigated using experimental and finite element (FE) modelling. The effect of ultrasonic vibrations on the induced residual stresses on the drawn steel tubes is evaluated using the mechanical and X-ray diffraction (×RD) method. The results indicate that the distribution of induced residual stresses mostly shows compressive stresses under ultrasonic vibrations. In contrast, the residual stresses are tensile in nature for conventionally drawn tubes, which are not very desirable. The experimental results show 11% reduction in draw load, while the FE analysis shows a 13% reduction in draw load, which indicates that the experimental and FE results are in good agreement. In addition, the effect of ultrasonic vibrations on the tensile strength, yield strength and percentage elongation is investigated and compared with samples from conventionally drawn tubes. The ultrasonic-assisted tube drawing has resulted in favourable tensile properties, which helps in improving the formability limit of the tubes. The Von Miss stress distribution obtained indicates that the ultrasonically assisted drawing results in a more uniform and lower Von Mises stress when compared to conventionally drawn tubes.
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    Dynamic stability analysis of stiffened shell panels with cutouts
    (ASCE, 2009-04) Patel, S. N.
    A finite element dynamic instability analysis of stiffened shell panels with cutout subjected to uniform in-plane harmonic edge loading along the two opposite edges is presented in this paper. The eight-noded isoparametric degenerated shell element and a compatible three-noded curved beam element are used to model the shell panels and the stiffeners, respectively. As the usual formulation of degenerated beam element is found to overestimate the torsional rigidity, an attempt has been made to reformulate it in an efficient manner. Moreover the new formulation for the beam element requires five degrees of freedom per node as that of shell element. Bolotin method is applied to analyze the dynamic instability regions. Numerical results of convergence studies are presented and comparison is made with the published results from literature. The effects of various parameters such as shell geometry, radius of curvature, cutout size, stiffening scheme, and dynamic load factors are considered in dynamic instability analysis of stiffened shell panels with cutout. The free vibration and static stability (buckling) results are also presented. With the consideration of radius of curvatures the panels reduce from deep shell case to shallow shell case and finally become flat plate.