Dynamic evolution of damage by microcracking with heat dissipation

• Published in: International journal of solids and structures Vol. 174-175; pp. 128 - 144
• Main Authors: Dascalu, Cristian, Gbetchi, Kokouvi
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 10-11-2019; Elsevier BV; Elsevier
• Subjects: Asymptotic methods; Compression tests; Computer simulation; Cooling rate; Crack initiation; Crack-tip heating; Damage assessment; Damage law; Dynamic propagation; Engineering Sciences; Fracture mechanics; Fracture toughness; Homogenization; Impact test; Mechanics; Micro-cracks; Microcracks; Microstructure; Parameter identification; PMMA; Propagation; Size effects; Solid mechanics; Strain rate; Temperature distribution; Thermal dissipation; Thermal evolution; Thermics; Thermoelasticity; Dynamic propagation; PMMA; Micro-cracks; Homogenization; Thermal dissipation; Damage law; Impact test; Crack-tip heating; homogenization; impact test; thermal dissipation; crack-tip heating; dynamic propagation; damage law
• ISSN: 0020-7683; 1879-2146
• DOI: 10.1016/j.ijsolstr.2019.05.026

A new thermo-mechanical damage model is constructed in the present contribution using a two-scale approach. The model is deduced from microstructures with microcracks evolving dynamically in a nominally brittle material and for which the fracture energy dissipated at the moving tips is converted to heat. The use of an homogenization method based on asymptotic developments leads to a damage evolution law coupled with the macroscopic thermoelasticity system. The obtained model accounts for inertial effects, thermo-elastic coupling and heat dissipation effects due to damage propagation. The local effective response of the model is analyzed with special emphasis on thermal evolutions. Strain-rate and microstructural size effects are illustrated. Cooling and heating regimes associated to damage initiation and propagation are identified and analyzed for different values of the model parameters. Results of numerical simulations for a compact compression specimen test are presented and compared with the experimental data for temperature field measurements during rapid failure of PMMA samples. Good agreement is found between the model predictions and the measured thermal evolution.