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MultiScale Mechanics of Materials

MultiScale Mechanics of Materials lab logo

Tennessee State University
Discrete to Continuum Bridging: Modeling and Experimental Characterization
Professor Ranganathan Parthasarathy

July 2020

Problems

Engineering problems such as mechano-sorptive behavior in polymers, amorphization of single crystals, hydrogen embrittlement in metals necessarily involve multi-physics multi-scale phenomena. A strong bridge between the mechanics and underlying material science is required to improve of current materials and further the understanding of natural materials.

Approach

We develop continuum scale constitutive laws which incorporate crucial information from smaller scales so that underlying mechanisms of material behavior are captured in the continuum scale model. This approach creates a synergy between helps accelerate development of new materials . Our approach is in the spirit of "Materials by Design". Materials which we study include crosslinked biomedical polymers and single crystals. We employ multi-physics characterization tools to validate our model from independent angles.

Findings

Our most recent finding shows that atomic-level residual strains associated with structural heterogeneity can be determined from a purely kinematic viewpoint. In previous work, we have demonstrated that vibrational spectroscopy can be used to study the nature of binding between solvent molecules and polymer chains to explain the resulting softening and mechano-sorptive behavior of crosslinked polymers.

Impact

We currently aim to strongly influence current methods of modeling alloys with no long range order such as HEA, BMG, and CSA using our new atomistic-to-continuum bridging approach. We have shown how granular micromechanics can be used to obtain a continuum interpretation of materials even at atomic scales. Our work in the area of polymer-solvent interaction and resulting mechanics has impacted bioadhesive development, mechanics of chemically attacked reinforced concrete, design of disposable gloves, and so on.

Selected Publications

  1. R. Parthasarathy, A. Misra, L. Song, Q. Ye, and P. Spencer, " Structure-Property relationships for wet dentin-adhesive polymers ," Biointerphases, 2018, doi: https://doi.org/10.1116/1.5058072.
  2. R. Parthasarathy " Thermal vibration contribution to continuum stress in the elastic regime ." Mechanics Research Communications, 2018, doi: https://doi.org/10.1016/j.mechrescom.2018.08.009. 
  3. R. Parthasarathy, Misra, A. and Ouyang, L. " Finite-temperature Stress Calculations in Atomic Models using Moments of Position ." J. Physics Condensed Matter, vol. 30, no. 26, pp. 265901, 2018, doi: https://doi.org/10.1088/1361-648X/aac52f 
  4. R. Parthasarathy, Misra, A., Aryal. S.R., and Ouyang, L. " Phonon Dispersion Evolution in Uniaxially Strained Aluminum Crystal ." Continuum Mechanics and Thermodynamics, 2018, doi: https://doi.org/10.1007/s0016 
  5. A. Misra, R. Parthasarathy, V. Singh, and P. Spencer, " Micro-poromechanics model of fluid-saturated chemically active fibrous media ," ZAMM Zeitschrift fur Angew. Math. und Mech., vol. 95, no. 2, pp. 215-234, 2015, doi: 10.1002/zamm.201300071
  6. A. Misra, R. Parthasarathy, Q. Ye, V. Singh, and P. Spencer, " Swelling equilibrium of dentin adhesive polymers formed on the water-adhesive phase boundary: Experiments and micromechanical model ," Acta Biomater., vol. 10, no. 1, pp. 330-342, 2014, doi: 10.1016/j.actbio.2013.09.017
  7. A. Misra, R. Parthasarathy, V. Singh, and P. Spencer, " Poromechanics parameters of fluid-saturated chemically active fibrous media derived from a micromechanical approach ," J. Nanomechanics Micromechanics, vol. 3, no. 4, p. 4013002, 2013, doi: 10.1061/(ASCE)NM.2153-5477.0000069
  8. V. Singh, A. Misra, R. Parthasarathy, Q. Ye, J. Park, and P. Spencer, " Mechanical properties of methacrylate-based model dentin adhesives: Effect of loading rate and moisture exposure ," J. Biomed. Mater. Res. Part B Appl. Biomater., vol. 101, no. 8, pp. 1437-1443, 2013, doi: 10.1002/jbm.b.32963
  9. Q. Ye, R. Parthasarathy, F. Abedin, J. S. Laurence, A. Misra, and P. Spencer, " Multivariate analysis of attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopic data to confirm phase partitioning in methacrylate-based dentin adhesive ," Appl. Spectrosc., vol. 67, no. 12, pp. 1473-1478, 2013, doi: 10.1366/13-07179
  10. Parthasarathy, R., A. Misra, J. Park, Q. Ye and P. Spencer (2012). " Diffusion coefficients of water and leachables in methacrylate-based crosslinked polymers using absorption experiments ." Journal of Materials Science: Materials in Medicine 23(5): 1157-1172, doi: 10.1007/s10856-012-4595-5
  11. R. Parthasarathy, G. Thiagarajan, X. Yao, Y.-P. Wang, P. Spencer, and Y. Wang, " Application of multivariate spectral analyses in micro-Raman imaging to unveil structural/chemical features of the adhesive/dentin interface ," J. Biomed. Opt., vol. 13, no. 1, p. 14020, 2008, doi: 10.1117/1.2857402 






Core Competencies

  • Atomistic-to-Continuum Bridging
  • Granular Micromechanics
  • Multiphysics Material Characterization
  • Micro-Chemo-Poro-Mechanics

Ranganathan Parthasarathy image
Research Projects

Current Members

  • Yahaira Corona (M.S. Student)
  • Joshua Stokely (Undergraduate Student)
  • Alydia Young (Undergraduate Student)

 

Funding Agency  

  • Department of Energy

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