PSI - Issue 28

Giacomo Risitano et al. / Procedia Structural Integrity 28 (2020) 1449–1457 G. Risitano et al./ Structural Integrity Procedia 00 (2019) 000–000

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The reason of the different temperature trends (experimental and simulated) may reside in the presence within the material of local defects that lead to local plastic condition, hence to a temperature rise. Actually it not easy to properly simulate such micro-defects adopting the FEM techniques. 5. Conclusions In this work the energetic release during a tensile test of a C45 steel has been evaluated. The IR camera allowed the application of the Static Thermographic Method monitoring the specimen’s surface temperature under adiabatic conditions. It has been possible to assess the limit stress of the material (222.2±4.0 MPa) as the macroscopic stress at which a deviation from the linearity of the thermoelastic effect is noticed. An elasto-plastic finite element analysis has been carried out on the same specimen geometry and compared with the experimental temperature trend, showing how the presence of internal micro-defect within the material leads to an increase in the temperature due to plastic deformation. Knowing the value of the limit stress from a static traction test, it is possible, by means of the Static Thermographic Method, to predict the fatigue behavior of the material, even with a limited number of specimens and in a short amount of time. Biot, M.A., 1956. Thermoelasticity and irreversible thermodynamics. J. Appl. Phys. 27, 240–253. https://doi.org/10.1063/1.1722351 Clienti, C., Fargione, G., La Rosa, G., Risitano, A., Risitano, G., 2010. A first approach to the analysis of fatigue parameters by thermal variations in static tests on plastics. Eng. Fract. Mech. 77, 2158–2167. https://doi.org/10.1016/j.engfracmech.2010.04.028 Colombo, C., Vergani, L., 2019. Thermographic applications for the rapid estimation of fatigue limit. Procedia Struct. Integr. 24, 658–666. https://doi.org/10.1016/j.prostr.2020.02.058 Corigliano, P., Cucinotta, F., Guglielmino, E., Risitano, G., Santonocito, D., 2020. Fatigue assessment of a marine structural steel and comparison with Thermographic Method and Static Thermographic Method. Fatigue Fract. Eng. Mater. Struct. 43, 734–743. https://doi.org/10.1111/ffe.13158 Crupi, V., Guglielmino, E., Risitano, G., Tavilla, F., 2015. Experimental analyses of SFRP material under static and fatigue loading by means of thermographic and DIC techniques. Compos. Part B Eng. 77, 268–277. https://doi.org/10.1016/j.compositesb.2015.03.052 Curà, F., Gallinatti, A.E., 2011. Fatigue damage identification by means of modal parameters, in: Procedia Engineering. Elsevier B.V., pp. 1697– 1702. https://doi.org/10.1016/j.proeng.2011.04.283 Foti, P., Santonocito, D., Ferro, P., Risitano, G., Berto, F., 2020. Determination of Fatigue Limit by Static Thermographic Method and Classic Thermographic Method on Notched Specimens. Procedia Struct. Integr. 26, 166–174. https://doi.org/10.1016/j.prostr.2020.06.020 Guglielmino, E., Risitano, G., Santonocito, D., Guglielmino, E., Risitano, G., Santonocito, D., 2020. A new approach to the analysis of fatigue parameters by thermal variations during tensile tests on steel. Procedia Struct. Integr. 24, 651–657. https://doi.org/10.1016/j.prostr.2020.02.057 Huang, J., Li, C., Liu, W., 2020. Investigation of internal friction and fracture fatigue entropy of CFRP laminates with various stacking sequences subjected to fatigue loading. Thin-Walled Struct. 155, 106978. https://doi.org/10.1016/j.tws.2020.106978 Jiang, L., Wang, H., Liaw, P.K., Brooks, C.R., Klarstrom, D.L., 2004. Temperature evolution during low-cycle fatigue of ULTIMET® alloy: Experiment and modeling. Mech. Mater. 36, 73–84. https://doi.org/10.1016/S0167-6636(03)00032-2 La Rosa, G., Risitano, A., 2000. Thermographic methodology for rapid determination of the fatigue limit of materials and mechanical components. Int. J. Fatigue 22, 65–73. https://doi.org/10.1016/S0142-1123(99)00088-2 LY, H.A., INOUE, H., IRIE, Y., 2011. Numerical Simulation on Rapid Evaluation of Fatigue Limit through Temperature Evolution. J. Solid Mech. Mater. Eng. 5, 459–475. https://doi.org/10.1299/jmmp.5.459 Pitarresi, G., Patterson, E.A., 2003. A review of the general theory of thermoelastic stress analysis. J. Strain Anal. Eng. Des. 38, 405–417. https://doi.org/10.1243/03093240360713469 Ricotta, M., Meneghetti, G., Atzori, B., Risitano, G., Risitano, A., 2019. Comparison of Experimental Thermal Methods for the Fatigue Limit Evaluation of a Stainless Steel. Metals (Basel). 9, 677. https://doi.org/10.3390/met9060677 Rigon, D., Ricotta, M., Meneghetti, G., 2019. Analysis of dissipated energy and temperature fields at severe notches of AISI 304L stainless steel specimens. Frat. ed Integrita Strutt. 13, 334–347. https://doi.org/10.3221/IGF-ESIS.47.25 References