Sisir Dhara

@mnnit.ac.in

Assistant Professor, Department of Mechanical Engineering
Motilal Nehru National Institute of Technology (MNNIT) Allahabad

Sisir Dhara


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https://researchid.co/sisirdhara
Dr. Sisir Dhara is currently working as an Assistant Professor at The Department of Mechanical Engineering, MNNIT Allahabad, India. Earlier he worked as a postdoctoral research fellow at WMG, University of Warwick, UK. He obtained his PhD degree in Engineering from WMG, University of Warwick, UK. He received his M. Tech degree from the Department of Mechanical Engineering, IIT Kharagpur, India and B. Tech degree from the Production Engineering Department, Jadavpur University, India.

EDUCATION

Undergraduate: Bachelor of Engineering (B.E.) in Production Engineering (First Class with Honors), Production Engineering Department, Jadavpur University
Postgraduate: Master of Technology (M.Tech.) in Manufacturing Science and Engineering (Departmental Topper, Institute Silver Medalist), Mechanical Engineering Department, IIT Kharagpur
Doctoral: Doctor of Philosophy ( in Engineering, Warwick Manufacturing Group (WMG), University of Warwick
Post Doctoral: Warwick Manufacturing Group (WMG), University of Warwick

RESEARCH, TEACHING, or OTHER INTERESTS

Mechanical Engineering, Materials Science, Industrial and Manufacturing Engineering
16

Scopus Publications

280

Scholar Citations

7

Scholar h-index

5

Scholar i10-index

Scopus Publications

  • Fracture Behaviour of DP800 Steel Under Different Strain Paths
    Sisir Dhara, Niluja Pakiyaraja, Yi Gao, Andrew Ruthven, Sumit Hazra
    Transactions of the Indian Institute of Metals, 2026
  • These ones are small; those ones are far away: A comparison of macro and in-situ micro tensile testing techniques
    S. Taylor, S. Dhara, R. Beaumont, S. Krauss, A. Zeybek, G.D. West
    Materialia, 2025
    An aluminium AA7020 alloy was investigated in both the as received cold rolled condition and in the w-temper condition after heat treatments in both macro tensile and in-situ micro tensile tests to verify test parameters for in-situ testing to improve understanding of the validity of micro results to bulk properties. A variety of macro scale geometries conforming to ISO standards, and micro scale geometries were tested in the as received cold rolled condition to identify the optimal thickness of tensile samples to replicate bulk physical properties. Both macro and micro DIC (digital image correlation) techniques were utilised to confirm accurate strain paths in said geometries. W-temper specimens were then subjected to interrupted EBSD (electron back-scattered diffraction) scans during in-situ tensile tests to understand the microstructural evolution of the material during deformation and understand what impact the pauses in deformation have on physical properties. This study identified that for accurate physical properties to be derived from in-situ micro samples they need to be thinned to achieve a width to thickness ratio of around 5, and that interrupted tests significantly alter the UTS (ultimate tensile strength) and strain to failure so need to be combined with non-interrupted tests to derive accurate properties.
  • Optimizing formability of incremental sheet forming using the straight groove test assessed with a variable wall angle conical frustum
    Ravi Prakash Singh, Santosh Kumar, Edward James Brambley, Sudarshan Choudhary, Pankaj Kumar Singh, Sisir Dhara
    Manufacturing Letters, 2025
    The current study is focused on Robot Assisted Incremental Sheet Forming (RAISF) of AA 6061 alloys. A simple and streamlined approach is presented to optimize the forming parameters to maximize formability during RAISF; the forming parameters are the tool speed, the step depth, and the tool diameter. The optimized parameters are found using a Design of Experiments (DOE) methodology applied to a straight groove test. Straight groove tests were conducted on 39 samples chosen according to a Central Composite Response Surface Design (CCRSD) methodology. Formability is assessed by considering the groove depth, spring back, and forming time; the combination of tool speed ( 84.65 , mm / s ), tool diameter ( 12.5 mm ) and step depth ( 0.4 mm ) were found optimal. A Variable Wall Angle Conical Frustum (VWACF) was then fabricated to assess the effect of the optimized parameters on the limiting conical wall angle. Finally, a conical frustum of constant wall angle 60 ∘ was fabricated, and its forming limit compared with the conventional forming limit of AA 6061 obtained by a Nakajima test.
  • Elucidating the deformation behaviour of DX54 steel under a continuous strain path change
    Sisir Dhara, Rahul Rakshit, Sumit Hazra, Sumantra Mandal, Sushanta Kumar Panda
    Journal of Materials Research and Technology, 2025
    Continuous strain path changes significantly influence material formability in industrial stamping. A deeper understanding of this effect requires investigating the evolution of crystallographic texture and the underlying deformation mechanisms. This study investigates the impact of a uniaxial to biaxial continuous strain path change on the microstructure and texture evolution of DX54 steel. Cruciform samples were tested in-situ using electron backscatter diffraction in a scanning electron microscope (SEM), with additional digital image correlation experiments conducted outside the SEM to monitor strain evolution. The uniaxial path accumulated higher effective strain before the transition, resulting in a more pronounced texture than in the subsequent biaxial path, particularly along the α - and γ -fibers. Visco-plastic self-consistent (VPSC) simulations were used to predict texture evolution and elucidate the dominant deformation mechanisms. VPSC simulations incorporating latent hardening yielded more accurate texture predictions than those with isotropic hardening, especially in the uniaxial path. VPSC results indicated a sharp increase in active slip systems during the strain path change. A transition in slip activity was observed, with {110}<111> slip decreasing and {112}<111> slip becoming dominant at later stages of deformation in both strain paths. This enhanced {112}<111> activity contributed to the strengthening of the α -fiber at the {114}<110> and γ -fiber at the {111}<110> texture components, thereby influencing strain hardening behaviour during deformation along both strain paths. • Studied in-situ texture during continuous uniaxial to biaxial strain path change • Conducted VPSC simulation to elucidate mechanism during strain path change • Latent hardening predicted texture evolution more accurately than isotropic hardening • Sharp increase in active slip systems was observed during strain path transition • Increased {112}<111> slip system activity influenced strain hardening behaviour
  • Effect of continuous and discontinuous non-proportional loadings on formability of DX54 sheet material
    Sisir Dhara, Scott Taylor, Łukasz Figiel, Sumit Hazra
    Journal of Manufacturing Processes, 2024
    Both continuous and discontinuous non-proportional loadings occur in multi-stage automotive stamping processes. Discontinuous loading is widely studied, but due to requiring sophisticated experimental procedures, continuous loading has been studied less. This study explores the impact of continuous loading on DX54 steel utilising an innovative experimental setup that enabled cruciform samples to undergo uniaxial to biaxial strain path change continuously without unloading. A similar two-stage discontinuous loading from uniaxial to biaxial with unloading in between was generated in DX54 to understand the differences in macro-strain, micro-strain, microstructure, and micro-texture evolution between the continuous and the discontinuous loadings. The stress state of the material during continuous loading was different to that during discontinuous loading. In this study, the occurrence of ‘pseudo-localisation’ was observed during continuous loading, and the observed rotation of high-strain bands differed between continuous and discontinuous loading. The discontinuous loading induced a higher strain, hardening rate, and increased elongation compared to the continuous loading. These results suggest the potential for higher formability during the discontinuous loading compared to the continuous loading. • Studied differences between continuous and discontinuous non-proportional loadings. • Examined strain, microstructure and texture evolution inside SEM chamber in-situ. • Occurrence of ‘pseudo-localisation’ and rotation of high-strain band were observed. • Stress state of DX54 steel varies from continuous to discontinuous loading. • Higher formability potential in discontinuous loading than in continuous loading.
  • An X-ray diffraction study of the influence of linear and changing strain paths on strain and texture evolution in AA6111-T4 aluminium alloy sheets
    Sisir Dhara, Darren J. Hughes, Steven Huband, Scott Taylor, Sumit Hazra
    Materialia, 2024
    Multi-stage automotive stamping processes involve both linear and changing strain paths. While extensive research exists on linear strain paths and discontinuous strain path change, the study of continuous strain path change is limited due to the need for sophisticated experimental procedures. In this paper, the effect of continuous strain path change on strain, strain hardening behaviour, microstructure, and texture evolution was compared with that of discontinuous strain path change in AA6111-T4 aluminium alloy using a novel experimental setup comprising an in-situ mechanical rig and cruciform sample. An X-ray source was used to obtain diffraction patterns, which were analysed to measure diffraction intensities and lattice strains at the {111}, {200}, {220} and {311} lattice planes to study strain hardening behaviour, microstructure, and texture evolution during the loading paths. The experiments were repeated outside the X-ray diffraction chamber to study macroscopic strain evolution and hardening behaviour of the samples using a digital image correlation system. It was found that the absence of unloading and reloading in the continuous strain path change posed challenges for plastic deformation in the next deformation stage, leading to strain softening, premature failure, and relatively weaker textural development. Conversely, the presence of unloading and reloading in the discontinuous strain path change facilitated increased plastic deformation in the next deformation stage, resulting in strain hardening, delayed failure, and stronger textural development.
  • The non-proportional loading of mild steel
    Sumit HAZRA
    Materials Research Proceedings, 2024
    The effect of proportional loading on formability has been extensively studied. However, non-proportional loading occurs frequently in a stamping operation and its impact on formability has been studied less. Non-proportional loading occurs in two areas of stamping: continuously during the draw stage of a complex geometry and discontinuously through stamping stages. Studies on non-proportionality (eg. [1]) show that it can change the formability of a material compared to when it is loaded proportionally. This paper introduces an experimental method that allows a comparison of the deformation in mild steel subject to continuous and discontinuous loading mechanisms. A notable innovation of the method is that it can be carried out inside the chamber of a scanning electron microscope, allowing in-situ measurements of plastic deformation. The experiments show that the plastic behavior of the material under the continuous mode is distinct to when it is deformed discontinuously
  • Utilising blue laser over infrared laser to enhance control of penetration depth and weld strength for producing electric vehicle battery interconnects
    Sisir Dhara, Mathew Finuf, Mark Zediker, Iain Masters, Anup Barai, Abhishek Das
    Journal of Materials Processing Technology, 2023
  • Identifying Optimal Hot Forming Conditions for AA6010 Alloy by Means of Elevated Temperature Tensile Testing
    Scott Taylor, Sisir Dhara, Carl Slater, Hiren Kotadia
    Metals, 2023
    AA6010 in the F temper was investigated using a Gleeble 3800 test rig across a range of temperatures (350–550 °C) and strain rates (1 × 10−1 s−1 1 × 101 s−1) to identify optimal forming conditions. Post-forming electron back-scattered diffraction analysis was conducted to identify the mechanisms responsible for the material formability. Optimal forming conditions were observed to be 500 °C and a strain rate of 1 × 10−1 s−1, with clear evidence of dynamic recrystallisation observed, this being the dominant mechanism responsible for the increased formability. Peak yield strength of 335 MPa was achieved using a rapid aging treatment of 205 °C for one hour.
  • Substituting Resistance Spot Welding with Flexible Laser Spot Welding to Join Ultra-Thin Foil of Inconel 718 to Thick 410 Steel
    Nikhil Kumar, Sisir Dhara, Iain Masters, Abhishek Das
    Materials, 2022
    This paper investigated various aspects of replacing existing micro-resistance spot welding (micro-RSW) with micro-laser spot welding for joining Inconel 718 thin foils to thick 410 steel stack-up to allow faster, non-contact joining together with flexibility in spot positioning and removal of tip dressing required for RSW electrodes. The joint quality was evaluated based on the mechanical strength, microstructural characteristics and joint strength at elevated temperature as these joints are often used for high-temperature applications. Experimental investigations were performed using micro-RSW and micro-laser spot welding to obtain the 90° peel and lap shear specimens, each comprising four spots. The obtained strength from laser joints was significantly higher than that of micro-RSW joints due to larger weld nugget formation and interface width. The process map for obtaining good quality welds was also identified, and about a 17% reduction in joint strength was obtained when welded specimens were subjected to elevated temperature (i.e., 500 °C) in comparison with room temperature. This reduction was compensated for using the flexibility of laser welding to add two extra spots. The overall performance of the micro-laser spot welds was found to be better than the micro-RSW considering joint strength, flexibility in placing the spots and time to produce the welds.
  • Development of a novel testing methodology for in-situ microstructural characterisation during continuous strain path change
    Sisir Dhara, Scott Taylor, Łukasz Figiel, Darren Hughes, Sumit Hazra
    Materials Characterization, 2022
  • A Novel Testing Methodology for In Situ Microstructural Characterisation During Continuous Strain Path Change
    Sisir Dhara, Scott Taylor, Łukasz Figiel, Darren Hughes, Barbara Shollock, Sumit Hazra
    Minerals Metals and Materials Series, 2022
  • In-situ study of strain and texture evolution during continuous strain path change
    Sisir Dhara, Scott Taylor, Łukasz Figiel, Darren Hughes, Barbara Shollock, Sumit Hazra
    Esaform 2021 24th International Conference on Material Forming, 2021
  • A novel experimental set-up for in-situ microstructural characterization during continuous strain path change
    S Dhara, S Taylor, Ł Figiel, B Shollock, S Hazra
    Iop Conference Series Materials Science and Engineering, 2020
  • Impact of ultrasonic welding on multi-layered Al–Cu joint for electric vehicle battery applications: A layer-wise microstructural analysis
    Sisir Dhara, Abhishek Das
    Materials Science and Engineering A, 2020
  • Formability analysis of pre-strained AA5754-O sheet metal using Yld96 plasticity theory: Role of amount and direction of uni-axial pre-strain
    S. Dhara, S. Basak, S.K. Panda, S. Hazra, B. Shollock, R. Dashwood
    Journal of Manufacturing Processes, 2016

RECENT SCHOLAR PUBLICATIONS

  • Fracture Behaviour of DP800 Steel Under Different Strain Paths
    S Dhara, N Pakiyaraja, Y Gao, A Ruthven, S Hazra
    Transactions of the Indian Institute of Metals 79 (6), 102 , 2026
    2026.0
  • These Ones are Small; Those Ones are Far Away: A Comparison of Macro and In-Situ Micro Tensile Testing Techniques
    S Taylor, S Dhara, R Beaumont, S Krauss, A Zeybek, GD West
    Materialia, 102533 , 2025
    2025.0
    Citations: 1
  • Optimizing formability of incremental sheet forming using the straight groove test assessed with a variable wall angle conical frustum
    RP Singh, S Kumar, EJ Brambley, S Choudhary, PK Singh, S Dhara
    Manufacturing Letters 44, 453-465 , 2025
    2025.0
    Citations: 2
  • Elucidating the deformation behaviour of DX54 steel under a continuous strain path change
    S Dhara, R Rakshit, S Hazra, S Mandal, SK Panda
    Journal of Materials Research and Technology 37, 2627-2642 , 2025
    2025.0
    Citations: 3
  • Effect of continuous and discontinuous non-proportional loadings on formability of DX54 sheet material
    S Dhara, S Taylor, Ł Figiel, S Hazra
    Journal of Manufacturing Processes 131, 463-477 , 2024
    2024.0
    Citations: 6
  • An X-ray diffraction study of the influence of linear and changing strain paths on strain and texture evolution in AA6111-T4 aluminium alloy sheets
    S Dhara, DJ Hughes, S Huband, S Taylor, S Hazra
    Materialia 38, 102305 , 2024
    2024.0
    Citations: 9
  • The non-proportional loading of mild steel
    S HAZRA, S DHARA, S TAYLOR, Ł FIGIEL
    Materials Research Proceedings 41 , 2024
    2024.0
    Citations: 3
  • Utilising blue laser over infrared laser to enhance control of penetration depth and weld strength for producing electric vehicle battery interconnects
    S Dhara, M Finuf, M Zediker, I Masters, A Barai, A Das
    Journal of Materials Processing Technology 317, 117989 , 2023
    2023.0
    Citations: 33
  • Identifying Optimal Hot Forming Conditions for AA6010 Alloy by Means of Elevated Temperature Tensile Testing
    S Taylor, S Dhara, C Slater, H Kotadia
    Metals 13 (1), 76 , 2022
    2022.0
    Citations: 1
  • A novel testing methodology for in situ microstructural characterisation during continuous strain path change
    S Dhara, S Taylor, Ł Figiel, D Hughes, B Shollock, S Hazra
    NUMISHEET 2022: Proceedings of the 12th International Conference and … , 2022
    2022.0
    Citations: 3
  • A Novel Testing Methodology for In Situ Microstructural Characterisation During
    S Dhara, S Taylor, Ł Figiel, D Hughes, B Shollock
    NUMISHEET 2022: Proceedings of the 12th International Conference and … , 2022
    2022.0
  • Substituting resistance spot welding with flexible laser spot welding to join ultra-thin foil of Inconel 718 to thick 410 steel
    N Kumar, S Dhara, I Masters, A Das
    Materials 15 (9), 3405 , 2022
    2022.0
    Citations: 15
  • A novel experimental methodology for in-situ material characterisation during various strain path change conditions
    S Dhara
    University of Warwick , 2022
    2022.0
  • Development of a novel testing methodology for in-situ microstructural characterisation during continuous strain path change
    S Dhara, S Taylor, Ł Figiel, D Hughes, S Hazra
    Materials Characterization 183, 111610 , 2022
    2022.0
    Citations: 10
  • In-situ study of strain and texture evolution during continuous strain path change
    S Dhara, S Taylor, Ł Figiel, D Hughes, B Shollock, S Hazra
    Prof. Anne Marie Habraken , 2021
    2021.0
    Citations: 5
  • A novel experimental set-up for in-situ microstructural characterization during continuous strain path change
    S Dhara, S Taylor, Ł Figiel, B Shollock, S Hazra
    IOP Conference Series: Materials Science and Engineering 967 (1), 012007 , 2020
    2020.0
    Citations: 8
  • Impact of ultrasonic welding on multi-layered Al–Cu joint for electric vehicle battery applications: A layer-wise microstructural analysis
    S Dhara, A Das
    Materials Science and Engineering: A 791, 139795 , 2020
    2020.0
    Citations: 131
  • Formability analysis of pre-strained AA5754-O sheet metal using Yld96 plasticity theory: Role of amount and direction of uni-axial pre-strain
    S Dhara, S Basak, SK Panda, S Hazra, B Shollock, R Dashwood
    Journal of Manufacturing Processes 24, 270-282 , 2016
    2016.0
    Citations: 50
  • In-situ study of strain and texture evolution during continuous strain path change
    S Dhara, S Taylor, Ł Figiel, D Hughes, B Shollock, S Hazra, SD WMG, ...

MOST CITED SCHOLAR PUBLICATIONS

  • Impact of ultrasonic welding on multi-layered Al–Cu joint for electric vehicle battery applications: A layer-wise microstructural analysis
    S Dhara, A Das
    Materials Science and Engineering: A 791, 139795 , 2020
    2020.0
    Citations: 131
  • Formability analysis of pre-strained AA5754-O sheet metal using Yld96 plasticity theory: Role of amount and direction of uni-axial pre-strain
    S Dhara, S Basak, SK Panda, S Hazra, B Shollock, R Dashwood
    Journal of Manufacturing Processes 24, 270-282 , 2016
    2016.0
    Citations: 50
  • Utilising blue laser over infrared laser to enhance control of penetration depth and weld strength for producing electric vehicle battery interconnects
    S Dhara, M Finuf, M Zediker, I Masters, A Barai, A Das
    Journal of Materials Processing Technology 317, 117989 , 2023
    2023.0
    Citations: 33
  • Substituting resistance spot welding with flexible laser spot welding to join ultra-thin foil of Inconel 718 to thick 410 steel
    N Kumar, S Dhara, I Masters, A Das
    Materials 15 (9), 3405 , 2022
    2022.0
    Citations: 15
  • Development of a novel testing methodology for in-situ microstructural characterisation during continuous strain path change
    S Dhara, S Taylor, Ł Figiel, D Hughes, S Hazra
    Materials Characterization 183, 111610 , 2022
    2022.0
    Citations: 10
  • An X-ray diffraction study of the influence of linear and changing strain paths on strain and texture evolution in AA6111-T4 aluminium alloy sheets
    S Dhara, DJ Hughes, S Huband, S Taylor, S Hazra
    Materialia 38, 102305 , 2024
    2024.0
    Citations: 9
  • A novel experimental set-up for in-situ microstructural characterization during continuous strain path change
    S Dhara, S Taylor, Ł Figiel, B Shollock, S Hazra
    IOP Conference Series: Materials Science and Engineering 967 (1), 012007 , 2020
    2020.0
    Citations: 8
  • Effect of continuous and discontinuous non-proportional loadings on formability of DX54 sheet material
    S Dhara, S Taylor, Ł Figiel, S Hazra
    Journal of Manufacturing Processes 131, 463-477 , 2024
    2024.0
    Citations: 6
  • In-situ study of strain and texture evolution during continuous strain path change
    S Dhara, S Taylor, Ł Figiel, D Hughes, B Shollock, S Hazra
    Prof. Anne Marie Habraken , 2021
    2021.0
    Citations: 5
  • Elucidating the deformation behaviour of DX54 steel under a continuous strain path change
    S Dhara, R Rakshit, S Hazra, S Mandal, SK Panda
    Journal of Materials Research and Technology 37, 2627-2642 , 2025
    2025.0
    Citations: 3
  • The non-proportional loading of mild steel
    S HAZRA, S DHARA, S TAYLOR, Ł FIGIEL
    Materials Research Proceedings 41 , 2024
    2024.0
    Citations: 3
  • A novel testing methodology for in situ microstructural characterisation during continuous strain path change
    S Dhara, S Taylor, Ł Figiel, D Hughes, B Shollock, S Hazra
    NUMISHEET 2022: Proceedings of the 12th International Conference and … , 2022
    2022.0
    Citations: 3
  • Optimizing formability of incremental sheet forming using the straight groove test assessed with a variable wall angle conical frustum
    RP Singh, S Kumar, EJ Brambley, S Choudhary, PK Singh, S Dhara
    Manufacturing Letters 44, 453-465 , 2025
    2025.0
    Citations: 2
  • These Ones are Small; Those Ones are Far Away: A Comparison of Macro and In-Situ Micro Tensile Testing Techniques
    S Taylor, S Dhara, R Beaumont, S Krauss, A Zeybek, GD West
    Materialia, 102533 , 2025
    2025.0
    Citations: 1
  • Identifying Optimal Hot Forming Conditions for AA6010 Alloy by Means of Elevated Temperature Tensile Testing
    S Taylor, S Dhara, C Slater, H Kotadia
    Metals 13 (1), 76 , 2022
    2022.0
    Citations: 1
  • Fracture Behaviour of DP800 Steel Under Different Strain Paths
    S Dhara, N Pakiyaraja, Y Gao, A Ruthven, S Hazra
    Transactions of the Indian Institute of Metals 79 (6), 102 , 2026
    2026.0
  • A Novel Testing Methodology for In Situ Microstructural Characterisation During
    S Dhara, S Taylor, Ł Figiel, D Hughes, B Shollock
    NUMISHEET 2022: Proceedings of the 12th International Conference and … , 2022
    2022.0
  • A novel experimental methodology for in-situ material characterisation during various strain path change conditions
    S Dhara
    University of Warwick , 2022
    2022.0
  • In-situ study of strain and texture evolution during continuous strain path change
    S Dhara, S Taylor, Ł Figiel, D Hughes, B Shollock, S Hazra, SD WMG, ...