Nelson Carvalho

Nelson De Carvalho

Senior Research Engineer

Tel: (757) 864-4505

Email: nelson.carvalho@nianet.org

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Research Interests

  • Experimental, analytical and numerical study of interacting failure modes in composite materials
  • High-fidelity modeling of progressive damage in composite materials
  • Novel numerical methods for modeling fracture and damage in solids
  • Micromechanics
  • Multiscale modeling

Education

  • Ph.D. (2012), Aeronautical Engineering, Imperial College London, United Kingdom.
  • M.S. (2006), Aerospace Engineering, Instituto Superior Técnico, Lisbon, Portugal

Current Research

  • Understanding and modeling interacting failure modes in advanced composite materials:

Typically, damage progress and failure of composite materials involves different and interacting failure modes, such as delamination, matrix cracking and fiber failure, amongst others. In recent years many advances have been made to characterize and model each of these individual failure modes. However, their interaction, often critical in determining failure, is not yet well understood nor modeled. The present research focuses on the study of the interaction between matrix cracking and delamination, which is considered key to confidently predict failure of composites under both static and fatigue loading. The main goal is to develop and validate novel analytical and numerical methods capable of accurately simulating this interaction. These tools are crucial to exploit fully the potential of advanced composite materials and expedite the design and certification of composite structures.

  • High-fidelity simulation of damage in composite materials:

Recent developments in numerical methods, such as XFEM (eXtended Finite Element Method), accompanied by an ever-increasing computational power have contributed to a great progress in the high-fidelity simulation of crack initiation and propagation in solids. In composite materials, the number and diversity of damage processes leading to failure have lead researchers to use and develop simplified semi-empirical models. These attempt to capture the fundamental features of the different damage mechanisms while avoiding complexities arising from modeling each damage mechanism explicitly. The present study focuses on developing and assessing novel numerical and analytical tools capable of explicitly simulating complex crack and damage networks. The primary goal is to reduce reliance on semi-empirical models and as consequence dramatically increase fidelity. Ultimately it aims at developing a methodology capable of supporting game-changing concepts that require ultra-realistic simulation capabilities, such as the digital-twin.

 

Book Chapters

  • N.V. De Carvalho and S.T. Pinho. Chapter in: Woven composites, Edited by M. H Aliabadi, Worldscientific, 2015. Link
  • S. T. Pinho, R. Gutkin, S. Pimenta, N. V. De Carvalho, P. Robinson. Chapter in: Failure mechanisms in polymer matrix composites: Criteria, testing and industrial applications, Edited by P Robinson, E S Greenhalgh and S Pinho, Imperial College London, UK, Woodhead Publishing Series in Composites Science and Engineering No. 40, 2012. Link

Journal Articles

  • N.V. De Carvalho, B.Y. Chen, S.T. Pinho, J.G. Ratcliffe, P.M. Baiz, T.E. Tay, Modeling delamination migration in cross-ply tape laminates, Composites Part A: Applied Science and Manufacturing, 71:192-203, 2015. Link
  • B.Y. Chen, S.T. Pinho, N.V. De Carvalho, P.M. Baiz, T.E. Tay, A floating node method for the modelling of discontinuities in composites, Engineering Fracture Mechanics, 127:104-134, 2014. Link
  • N.V. De Carvalho, S.T. Pinho, and P. Robinson. Analytical modelling of the compressive and tensile response of 2D woven composites. Composites Structures, 94(9):2724-2735, 2012. Link
  • N.V. De Carvalho, S.T. Pinho, and P. Robinson. Numerical modelling of 2D woven composites: biaxial loading. Composites Part A: Applied Science and Manufacturing, 43 (8):1326-1337, 2012. Link
  • S.T. Pinho, R. Gutkin, S. Pimenta, N. V. De Carvalho, P. Robinson. On longitudinal compressive failure of CFRP: from unidirectional to woven, and from virgin to recycled. Phil Trans Roy Soc A, 370 (1965):1871–1895, 2012. Link
  • N.V. De Carvalho, S.T. Pinho, and P. Robinson. Reducing the domain in the mechanical analysis of periodic structures, with application to woven composites. Composites Science and Technology, 71 (7):969–979, 2011. Link
  • N.V. De Carvalho, S.T. Pinho, and P. Robinson. An experimental study of failure initiation and propagation in 2D Woven composites under compression. Composites Science and Technology, 71 (10):1316–1325, 2011. Link

Peer Reviewed Conference Articles:

  • N.V. De Carvalho, J. G. Ratcliffe, B. Y. Chen, S. T. Pinho, P. M. Baiz, T. E. Tay. Modeling quasi-static and fatigue-driven delamination migration. In proceedings of the American Society for Composites, 29th Technical Conference on Composite Materials, San Diego, CA, United States, 2014.
  • N.V. De Carvalho, G. Murri. A novel method for characterizing fatigue delamination growth under mode I using the double cantilever beam specimen. In proceedings of the American Society for Composites, 29th Technical Conference on Composite Materials, San Diego, CA, United States, 2014.
  • N. V. De Carvalho, B. Y. Chen, S. T. Pinho, P. M. Baiz, J. G. Ratcliffe, T. E. Tay. Floating node method and virtual crack closure technique for modeling matrix cracking-delamination migration. 19th International Conference on Composite Materials (ICCM-19), Montreal, Canada, 28th of July to 2nd of August, 2013.
  • S. T. Pinho, B. Y. Chen, N. V. De Carvalho, P. M. Baiz, T. E. Tay. A floating node method for the modeling of discontinuities within a finite element. 19th International Conference on Composite Materials (ICCM-19), Montreal, Canada, 28th of July to 2nd of August, 2013.
  • S. T. Pinho, N. V. De Carvalho, P. Robinson. Analytical model to predict failure of woven composites. 18th International Conference on Composite Materials (ICCM-18), Jeju Island, Korea, 21th to 26th of August, 2011.
  • S. T. Pinho, N. V. De Carvalho, P. Robinson. Modelling the mechanical response of 2D woven composites. 16th International Conference on Composite Structures (ICCS16), Porto, Portugal, 28th to 30th of June, 2011.
  • S. T. Pinho, N. V. De Carvalho, P. Robinson. Analytical model for the compressive response of 2D woven composites. 5th International Conference on Composites Testing and Model Identification February 14, CompTest, Lausanne, 2011.
  • N. V. De Carvalho, S. T. Pinho, and P. Robinson, Compressive failure initiation of 2D woven composites. 14th  European Conference on Composite Materials (ECCM-14), Budapest, Hungary, 7th – 10th June 2010.
  • S. T. Pinho, N. V. De Carvalho, P. Robinson, Multiscale analysis of periodic structures. First International Conference on Multiscale Modelling. Ecole Nationale des Ponts et Chaussees, Paris, France, 1th-2th of September 2010.
  • N. V. De Carvalho, S. T. Pinho, and P. Robinson, Compressive failure of 2D woven composites. 15th International Conference on Composites Materials (ICCM-17), Edinburgh, UK, 27th – 31th Jul 2009.

Technical Publications

  • J. G. Ratcliffe, N. V. De Carvalho, Investigating Delamination Migration in Composite Tape Laminates, NASA/TM–2014-218289, 2014. Link
  • N. V. De Carvalho, Chen, B. Y.; Pinho, S. T.; Baiz, P. M.; Ratcliffe, J. G.; Tay, T. E., Floating Node Method and Virtual Crack Closure Technique for Modeling Matrix Cracking-Delamination Interaction, NASA/CR-2013-218022, 2013. Link