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Ravindra K. Saxena

Bio: Ravindra K. Saxena is an academic researcher from Sant Longowal Institute of Engineering and Technology. The author has contributed to research in topics: Welding & Finite element method. The author has an hindex of 6, co-authored 32 publications receiving 141 citations. Previous affiliations of Ravindra K. Saxena include Indian Institute of Technology Kanpur & Indian Institutes of Technology.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the effect of the tooling geometry and process parameters on the ear formation was studied, and it was shown that the uneven metal flow rate, rather than the material anisotropy, is mainly responsible for the earing.
Abstract: Deep drawing is an extensively used press working process since it eliminates expensive machining and welding operations and enables the production of components at a very high rate. The workpiece material used in a deep drawing process is anisotropic in nature, due to a prior thermomechanical treatment. Earing is one of the major defects observed in a deep drawing process due to the anisotropic nature of the sheet material. Knowledge about the ear formation in deep drawing allows a prior modification of the process, which can result in a defect-free final product with financial savings. In this paper, a recently proposed anisotropic yield criteria by Barlat et al. for rolled sheets is used to model the anisotropy for simulating the earing defect in square and circular cup drawing processes. The effect of the tooling geometry and process parameters on the ear formation is studied. It is shown that, in the square cup, the uneven metal flow rate, rather than the material anisotropy, is mainly responsible for the flange earing. Finite element formulation, based on the updated Lagrangian approach, is employed for the analysis. The stresses are updated in a material frame and the logarithmic strain measure is used, which allows the use of a large increment size. Isotropic hardening is assumed, and it follows a power law. Inertia forces are neglected due to small accelerations. The modified Newton–Raphson iterative technique is used to solve the nonlinear incremental equations.

31 citations

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TL;DR: In this article, the authors used the Hill's bifurcation criterion to predict the onset of flange wrinkling in circular and square cup drawing, and a parametric study of the maximum cup height was carried out with respect to various geometric, material and process parameters.

29 citations

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TL;DR: In this paper, the authors deal with the prediction of fracture initiation in a deep drawn cup using Lemaitre's continuum damage mechanics model, where the damage is incorporated in the constitutive equation through the principle of strain equivalence.

26 citations

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TL;DR: In this paper, an experiment based thermal analysis has been performed to obtain the thermal histories, which can be applied to determine cooling rate of weldment, and the effect of selected welding parameters (Wire feed rate, Open circuit Voltage and welding Speed) on the microhardness have been investigated.
Abstract: An experiment based thermal analysis has been performed to obtain the thermal histories, which can be applied to determine cooling rate of weldment. During fusion welding process it is possible to determine temperature at any point by using thermocouple and from such data it is possible to draw thermal histories for any point of interest, such thermal histories can be utilized to determine cooling rate. The temperature distribution and cooling rate during the welding process have significant effect on the mechanical and metallurgical properties of a weldment. The changes in microstructure, grain growth and hardness in a weldment are very dependent on the temperature distribution and cooling rate. These studies are utilized to investigate the micro-structure and microhardness of the heat affected zone (HAZ) and weldment. In present work, the influence of heat input and cooling rate on microhardness has been investigated. Full factorial design is used to conduct the experiment with three factors and two levels. Eight combinations and two set of heat input are designed with different combinations of SAW welding parameters. Temperature distribution curves and cooling rate have been drawn. The effect of selected welding parameters (Wire feed rate, Open circuit Voltage and welding Speed) on the microhardness have been investigated.

19 citations

Journal ArticleDOI
TL;DR: In this paper, a mathematical model is developed to incorporate the effect of latent heat of phase transformation using enthalpy formulation, and the accuracy of the developed model was initially validated using available results in the literature and found consistent prediction.
Abstract: The present study aims to evaluate the influence of latent heat effect during phase change in a three-dimensional finite element numerical simulation of arc welding. A mathematical model is developed to incorporate the effect of latent heat of phase transformation using enthalpy formulation. The accuracy of the developed model was initially validated using available results in the literature and found consistent prediction. The validated numerical model is used to predict the temperature distribution, weld width, depth of penetration, melting efficiency with and without incorporating the effect of latent heat of fusion, solidification vaporization. The results obtained from a developed model incorporating the latent heat effect are in good agreement with the experimentally measured values, whereas a considerable deviation is observed between the predicted values and experimental values without considering the effect of latent heat. It is found that without considering the latent heat effect in the model, the mean error is 14%, 24.6%, 22% and 29.6% for peak temperatures, weld width, depth of penetration and melting efficiency respectively. Therefore, it can be concluded that the effect of latent heat of fusion, solidification, and vaporization is significant for analysis involving phase change and must be accounted for during numerical simulations.

15 citations


Cited by
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Journal Article
TL;DR: This book by a teacher of statistics (as well as a consultant for "experimenters") is a comprehensive study of the philosophical background for the statistical design of experiment.
Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

13,333 citations

01 Jan 2016
TL;DR: Thank you for downloading numerical methods for scientific and engineering computation, instead of reading a good book with a cup of coffee in the afternoon, instead they are facing with some malicious bugs inside their laptop.
Abstract: Thank you for downloading numerical methods for scientific and engineering computation. Maybe you have knowledge that, people have search numerous times for their favorite readings like this numerical methods for scientific and engineering computation, but end up in malicious downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they are facing with some malicious bugs inside their laptop.

96 citations

Journal ArticleDOI
TL;DR: In this article, a hexahedral solid-shell finite element was validated in the field of sheet metal forming using the B-Bar method and a finite element formulation incorporating a finite strain material model for plastic anisotropy.

56 citations

Journal ArticleDOI
01 Mar 2019
TL;DR: In this article, there are various processes practiced in a market for manufacturing axisymmetrical cup with significant forming depth among which deep drawing process is most prompt, the deep drawing is a...
Abstract: There are various processes practiced in a market for manufacturing axisymmetrical cup with significant forming depth among which deep drawing process is most prompt. The deep drawing process is a ...

54 citations

Journal ArticleDOI
TL;DR: In this article, a new hybrid artificial intelligence approach is proposed to model the ultrasonic welding of a polymeric material blend, which is composed of an ensemble random vector functional link model (ERVFL) integrated with a gradient-based optimizer (GBO).
Abstract: In this study, a new hybrid artificial intelligence approach is proposed to model the ultrasonic welding of a polymeric material blend. The proposed approach is composed of an ensemble random vector functional link model (ERVFL) integrated with a gradient-based optimizer (GBO). First, welding experiments were conducted on acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) blends produced by the injection molding method. The experiments were designed according to the L27 orthogonal array considering three process factors (applied pressure, welding time, and vibration amplitude) and two responses (average temperature and joint strength). Then, the obtained experimental data were used to train the developed model. To verify the accuracy of the model, it was compared with standalone ERVFL in addition to two fine-tuned ERVFL models (ERVFL-SCA and ERVFL-MRFO) in which ERVFL is incorporated with sine cosine algorithm (SCA) or Manta ray foraging optimization (MRFO). The four models were evaluated using five statistical tools. ERVFL-GBO has the highest coefficient of determination and the lowest root mean square error, mean relative error mean absolute error, and coefficient of variance compared with other models which indicate its high accuracy over other tested models.

50 citations