Imperial College London
Portrait Picture

Professor Dan Balint

Faculty of Engineering, Department of Mechanical Engineering

Professor in Solid Mechanics
 
 
 
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Contact

 

+44 (0)20 7594 7084d.balint Website

 
 
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Location

 

519City and Guilds BuildingSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

188 results found

El Fakir O, Chen S, Wang L, Balint D, Dear JP, Lin Jet al., 2013, Numerical Investigation on the Hot forming and Cold-Die Quenching of an Aluminium-Magnesium Alloy into a Complex Component, LIGHT METALS TECHNOLOGY 2013, Vol: 765, Pages: 368-372, ISSN: 0255-5476

Journal article

Dunnett T, Balint D, MacGillivray H, Church P, Gould Pet al., 2012, Scale effects in necking, EPJ Web of Conferences, Vol: 26, ISSN: 2101-6275

Geometrically similar specimens spanning a scale range of 100:1 are tested quasi-statically to failure. Images of neck development are acquired using optical means for large specimens, and in-situ scanning electron microscope testing for small specimens, to examine the dependence of neck geometry on a broad range of specimen sizes. Size effects typically arise when the smallest specimen dimension is on the order of a microstructural length (e.g. grain size, dislocation mean free path, etc.), or in the presence of significant plastic strain gradients, which increase the density of geometrically necessary dislocations. This study was carried out for the purpose of investigating scale dependence in models used for predicting dynamic deformation and damage to very high strains for ballistic impact applications, such as the Goldthorpe path-dependent failure model, which includes temperature and strain-rate dependence but does not account for specimen size or a dependence on microstructural lengths. Although the experiments show that neck geometry does not exhibit a clear dependence on specimen size across the range of length scales tested, the statistical variation due to microstructural variations was found to increase monotonically with decreasing size, becoming significant for the smallest (0.35 mm diameter) size, allowing a limit to be identified for reliable model calibration. © Owned by the authors, 2012.

Journal article

Zhang P, Karimpour M, Balint D, Lin Jet al., 2012, Three-dimensional virtual grain structure generation with grain size control, MECHANICS OF MATERIALS, Vol: 55, Pages: 89-101, ISSN: 0167-6636

Journal article

Zhang P, Karimpour M, Balint D, Lin Jet al., 2012, Cohesive zone representation and junction partitioning for crystal plasticity analyses, INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Vol: 92, Pages: 715-733, ISSN: 0029-5981

Journal article

Zhang P, Karimpour M, Balint D, Lin J, Farrugia Det al., 2012, A controlled Poisson Voronoi tessellation for grain and cohesive boundary generation applied to crystal plasticity analysis, 21st International Workshop on Computational Mechanics of Materials (IWCMM), Publisher: ELSEVIER SCIENCE BV, Pages: 84-89, ISSN: 0927-0256

Conference paper

Ali A-H, Balint D, Temple A, Leevers Pet al., 2012, The reliability of defect sentencing in manual ultrasonic inspection, NDT & E INTERNATIONAL, Vol: 51, Pages: 101-110, ISSN: 0963-8695

Journal article

Lin J, Balint D, Pietrzyk M, 2012, Microstructure Evolution in Metal Forming Processes, Publisher: Woodhead Publishing, ISBN: 9780857090744

Recent research on the mechanisms, modeling, and control of microstructure evolution during metal forming processes are provided.

Book

Chen Y, Zhuang W, Wang S, Lin J, Balint D, Shan Det al., 2012, Investigation of FE Model Size Definition for Surface Coating Application, CHINESE JOURNAL OF MECHANICAL ENGINEERING, Vol: 25, Pages: 860-867, ISSN: 1000-9345

Journal article

Shi Z, Wang Y, Lin J, Dean T, balint D, Stanton M, Watson Det al., 2012, An Investigation, Using Standard Experimental Techniques, to Determine FLCs at Elevated Temperature for Aluminium Alloys, The 3rd International Conference on New Forming Technology

An experimental procedure has been developedfor the determination of FLCs at elevated temperatures. TheGOM ARGUS system was employed for measuring surfacestrain based on pre-applied grids (pattern), and limit strains weredetermined according to the ISO 12004-2:2008 standard.Forming limit curves (FLCs) have been determined for AA5754under warm forming conditions in an isothermal environment.The tests were carried out at various temperatures up to 300oCand forming speeds ranging from 5 – 300 mm s-1. Results revealthe significant effect of both temperature and forming speed onFLCs of AA5754. Formability increases with increasingtemperature above 200oC. Formability also increases withdecreasing speed. The presented FLC results show that the bestformability exists at low forming speed and the high temperatureend of the warm forming range.

Conference paper

Li N, Li X, Dry D, Dean TA, Lin Jet al., 2012, Investigation on the Mechanical Properties of As-Formed Boron Steels for Optimizing Process Strategies in Hot Stamping, Steel Research International

Journal article

Bai Q, Lin J, Zhan L, Dean TA, Balint DS, Zhang Zet al., 2012, An efficient closed-form method for determining interfacial heat transfer coefficient in metal forming, INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE, Vol: 56, Pages: 102-110, ISSN: 0890-6955

Journal article

Mohamed MS, Foster AD, Lin J, Balint DS, Dean TAet al., 2012, Investigation of deformation and failure features of AA6082: Experimentation and modelling, INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE, Vol: 53, Pages: 27-38, ISSN: 0890-6955

Journal article

Bai Q, Lin J, Zhan L, Dean TA, Balint DS, Zhang Zet al., 2012, A New Method for Determining Interfacial Heat Transfer Coefficient and its Application in Hot/Warm Forming, STEEL RESEARCH INTERNATIONAL, Pages: 1035-1038, ISSN: 1611-3683

Journal article

Zhuang W, Wang S, Lin J, Balint D, Hard Cet al., 2012, Experimental and numerical investigation of localized thinning in hydroforming of micro-tubes, EUROPEAN JOURNAL OF MECHANICS A-SOLIDS, Vol: 31, Pages: 67-76, ISSN: 0997-7538

Journal article

Karimpour M, Balint D, Lin J, 2012, crystal Plasticity Finite Element Modelling and Its Application in Micro-forming, STEEL RESEARCH INTERNATIONAL, Pages: 9-16, ISSN: 1611-3683

Journal article

Bai Q, Lin J, Balint DS, Dean TAet al., 2012, A Method to Reduce Localised Thinning in Superplastic Forming, STEEL RESEARCH INTERNATIONAL, Pages: 691-694, ISSN: 1611-3683

Journal article

Lin J, Cao J, Balint D, 2012, Determining unified constitutive equations for modelling hot forming of steel, MICROSTRUCTURE EVOLUTION IN METAL FORMING PROCESSES, Pages: 180-209

Journal article

Puncreobutr C, Lee PD, Kaye M, Balint D, Farrugia D, Connolley T, Lin Jet al., 2012, Quantifying damage accumulation during the hot deformation of free-cutting steels using ultra-fast synchrotron tomography, 13th International Conference on Modeling of Casting, Welding and Advanced Solidification Processes (MCWASP), Publisher: IOP PUBLISHING LTD, ISSN: 1757-8981

Conference paper

Betts C, Lin J, Balint D, Atkins Aet al., 2012, 2D FE Micromechanics Modelling of Honeycomb Core Sandwich Panels, Engineering Transactions, Vol: 60, Pages: 187-203, ISSN: 0867-888X

Journal article

Zhan L, Lin J, Balint D, 2012, Microstructure control in creep-age forming of aluminium panels, MICROSTRUCTURE EVOLUTION IN METAL FORMING PROCESSES, Pages: 298-336

Journal article

Mohamed M, Lin J, Balint D, 2011, An investigation of blank holding force in isothermal stamping of aluminium alloys, Proceedings of the 10th International Conference on Technology of Plasticity, ICTP 2011, Pages: 1051-1056

Wrinkling and fracture are the two important failure modes in hot stamping of aluminium alloy sheets. Control of the blank holding force (BHF) can eliminate these defects and improve the quality of formed parts. This paper presents the results of recent studies on the effects of blank holding force on the formability and wrinkling in hot stamping of rectangular parts. To simplify the problem, this work concentrates on isothermal stamping for an AA6082 aluminium alloy. A set of constitutive equations has been developed and calibrated by experimental data for AA6082 at different temperatures and strain rates. The calibrated constitutive equations were implemented in the commercial finite element code LS-DYNA via the user-defined material subroutine, UMAT A finite element forming process model was built for simulating hot stamping of a complex-shaped panel part to investigate the effect of BHF on the formability and wrinkling features. Further, forming process optimisation was carried out using the finite element model, with wrinkling and failure limits (the process window) identified for a model panel part The dependence of the BHF on temperature and sheet thickness were also identified. © 2011 IBF (RWTH Aachen) & IUL (TU Dortmund).

Journal article

Li N, Mohamed MS, Cai J, Lin J, Balint D, Dean TAet al., 2011, Experimental and Numerical Studies on the Formability of Materials in Hot Stamping and Cold Die Quenching Processes, The 14th International ESAFORM Conference on Material Forming, Publisher: American Institute of Physics, Pages: 1555-1561, ISSN: 0094-243X

Formability of steel and aluminium alloys in hot stamping and cold die quenching processes is studied in this research. Viscoplastic‐damage constitutive equations are developed and determined from experimental data for the prediction of viscoplastic flow and ductility of the materials. The determined unified constitutive equations are then implemented into the commercial Finite Element code Abaqus/Explicit via a user defined subroutine, VUMAT. An FE process simulation model and numerical procedures are established for the modeling of hot stamping processes for a spherical part with a central hole. Different failure modes (failure takes place either near the central hole or in the mid span of the part) are obtained. To validate the simulation results, a test programme is developed, a test die set has been designed and manufactured, and tests have been carried out for the materials with different forming rates. It has been found that very close agreements between experimental and numerical process simulation results are obtained for the ranges of temperatures and forming rates carried out.

Conference paper

Balint DS, Kim S-S, Liu Y-F, Kitazawa R, Kagawa Y, Evans AGet al., 2011, Anisotropic TGO rumpling in EB-PVD thermal barrier coatings under in-phase thermomechanical loading, ACTA MATERIALIA, Vol: 59, Pages: 2544-2555, ISSN: 1359-6454

Journal article

Wang L, Strangwood M, Balint D, Lin J, Dean TAet al., 2011, Formability and failure mechanisms of AA2024 under hot forming conditions, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, Vol: 528, Pages: 2648-2656, ISSN: 0921-5093

Journal article

Lin J, Cao J, Balint D, 2011, Development and determination of unified viscoplastic constitutive equations for predicting microstructure evolution in hot forming processes, International Journal of Mechatronics and Manufacturing Systems, Vol: 4, Pages: 387-401, ISSN: 1753-1039

This paper reports the development of advanced unified viscoplastic constitutive equations for the modelling of microstructure evolution and their effects on viscoplastic flow of materials. The material parameters within constitutive equations are determined by minimising the difference between predicted results and the corresponding experimental data. To achieve this, firstly, new methods have been developed to overcome different scale problems in a set of constitutive equations. This enables that all the equations can be integrated accurately with a specified single tolerance. Secondly, objective functions have been formulated to enable all the data to be optimised with equal opportunity. Thus, the selection of weighting factors is eliminated. Thirdly, based on the analysis of the failure of gradient-based, genetic algorithm (GA)-based and evolutionary programming (EA)-based optimisation techniques in determining the constants within constitutive equations, a new combined method has been proposed to increase the chance to get the global minimum. Copyright © 2011 Inderscience Enterprises Ltd.

Journal article

Zhuang W, Wang S, Balint D, Lin Jet al., 2011, Crystal Plasticity Finite Element Process Modeling for Hydro-forming Micro-tubular Components, CHINESE JOURNAL OF MECHANICAL ENGINEERING, Vol: 24, Pages: 78-83, ISSN: 1000-9345

Journal article

Zhan L, Lin J, Balint D, 2011, Review of materials and process modeling techniques for creep age forming, International Conference on Advances in Materials and Manufacturing Processes, Publisher: TRANS TECH PUBLICATIONS LTD, Pages: 1439-+, ISSN: 1022-6680

Conference paper

Zhang P, Balint D, Lin J, 2011, Controlled Poisson Voronoi tessellation for virtual grain structure generation: a statistical evaluation, PHILOSOPHICAL MAGAZINE, Vol: 91, Pages: 4555-4573, ISSN: 1478-6435

Journal article

Zhang P, Balint D, Lin J, 2011, An integrated scheme for crystal plasticity analysis: Virtual grain structure generation, Computational Materials Science, Vol: 50, Pages: 2854-2864

Journal article

Mohamed MS, Lin J, Wang L, Balint Det al., 2010, Hybrid forming processes for production of lightweight high strength automotive panel parts, International Heat Treatment and Surface Engineering, Vol: 4, Pages: 160-165, ISSN: 1749-5148

The research concentrates on a heat treatable AA 6082 aluminium alloy. A set of unified constitutive equations has been developed and determined from experimental data. In addition to modelling viscoplastic flow of the material at different temperatures, the equations contain other two specific features. One is to predict the failure of the material under various deformation conditions based on continuum damage mechanics theories. The other is to model the precipitation formation and growth under straining and aging conditions; thus, the strength distribution of formed parts can be predicted via process modelling. The determined unified constitutive equations are then implemented into the commercial finite element code ABAQUS/Explicit via the user defined subroutine, VUMAT. A finite element process simulation model and numerical procedures are established for the modelling of a hot stamping and cold die quenching processes for a spherical part with a central hole. To validate the simulation results, a test programme is developed, a test rig has been designed and manufactured and tests have been carried out under different forming rates. It has been found that very close agreements between experimental and numerical process simulation results are obtained for the range of forming rates carried out. © 2010 Maney Publishing.

Journal article

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