Qualification: 
Ph.D, M.Tech, BE
c_gokulnath@cb.amrita.edu

Dr. Gokulnath. C. currently serves as Assistant Professor (Sr.Gr.) at the department of Civil Engineering, School of Engineering, Amrita Vishwa Vidyapeetham, Coimbatore.

Education

  • 2018: Ph. D. (Structural Engineering)
    IIT Madras, Chennai
  • 2009: M. Tech. (Structural Engineering)
    IIT Madras, Chennai
  • 2007: B. E. (Civil Engineering)
    CEG, Anna University, Chennai

Scholastic Achievements and Scholarship

  • Secured All India Rank 10 in the Graduate Aptitude Test in Engineering (GATE) 2007.
  • Half Time Teaching Assistantship by MHRD, Govt. of India (2007 – 2009).
  • Half Time Research Assistantship by MHRD, Govt. of India (2013 – 2018).
  • Institute scholarship for attending European Solid Mechanics Conference, Madrid, Spain, 2015.

Experience

Month/ Year Affiliation
May 2011 – July 2013 Structural Engineer, Dar Al Handasah Consultants (Shair & Partners), Pune, India
June 2009 – April 2011 Structural Design Engineer, Francis Santiago and Associates, Chennai

Publications

Publication Type: Journal Article

Year of Publication Title

2019

C. Gokulnath, Varaprasad, D., and Saravanan, U., “A three dimensional constitutive model for plain cement concrete”, Construction and Building Materials, vol. 203, pp. 456-468, 2019.[Abstract]


The validity of some of the assumptions made during systematic development of constitutive relation – homogeneity, isotropy, and non-dissipative response – is examined experimentally by testing plain concrete cylinders in the circumferential displacement controlled uniaxial compression tests. The tested cylinders indicate that the surface strains are not uniform and that the principal direction of the strain varies with the magnitude of the applied load. Hence, these cylinders are either deforming from a stressed state or anisotropic or both. The percentage dissipation computed as the area between the loading and unloading curves normalized using the area under the unloading curve is less than 10 percent up to 90 percent of the peak load. Therefore the mechanical response of concrete can be considered as non-dissipative. Assuming that the magnitude of the residual stresses present in the concrete panels would be small compared to the stresses arising due to the applied load, these residual stresses are ignored. Consequently, using the implicit constitutive theory framework for isotropic and compressible materials undergoing a non-dissipative process from a stress-free reference configuration, a three-dimensional constitutive relation for plain concrete is proposed. The material parameters in the proposed model are estimated from the uniaxial compression test and equal biaxial compression test. These parameters are expressed using initial Young's modulus, initial Poisson's ratio, maximum uniaxial compressive stress, the axial and transverse strain corresponding to the maximum uniaxial compressive stress, maximum equal biaxial compressive stress and the equal biaxial strain corresponding to maximum equal biaxial compressive stress. The ability of the proposed model to capture the response of various grade and type of concrete in ten biaxial experiments reported in the literature is examined. It is found that despite the limiting assumptions, the compression-compression, compression-tension and tension-tension stress strain response of the concrete in these ten experiments are adequately captured by the proposed model with mean R 2 value of 0.94. © 2019 Elsevier Ltd

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2017

C. Gokulnath, Saravanan, U., and Rajagopal, K. R., “Representations for implicit constitutive relations describing non-dissipative response of isotropic materials”, Zeitschrift fur Angewandte Mathematik und Physik, vol. 68, pp. 129 – 143, 2017.[Abstract]


A methodology for obtaining implicit constitutive representations involving the Cauchy stress and the Hencky strain for isotropic materials undergoing a non-dissipative process is developed. Using this methodology, a general constitutive representation for a subclass of implicit models relating the Cauchy stress and the Hencky strain is obtained for an isotropic material with no internal constraints. It is shown that even for this subclass, unlike classical Green elasticity, one has to specify three potentials to relate the Cauchy stress and the Hencky strain. Then, a procedure to obtain implicit constitutive representations for isotropic materials with internal constraints is presented. As an illustration, it is shown that for incompressible materials the Cauchy stress and the Hencky strain could be related through a single potential. Finally, constitutive approximations are obtained when the displacement gradient is small. © 2017, Springer International Publishing AG.

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Publication Type: Conference Proceedings

Year of Publication Title

2016

C. Gokulnath, “A New Elastic Constitutive Relation for Plain concrete”, Structural Engineering Convention. Chennai, India, 2016.

2015

C. Gokulnath, “Constitutive Modeling of Rubber Using a New Class of Elasticity Models”, European Solid Mechanics Conference. Madrid, Spain, 2015.