PRANTL Antonín ŠKODA-JS a.s.

Identification of Ductile Damage Parameters - Experimental Part

Co-authors DŽUGAN Jan, KONOPÍK Pavel

Paper deals with ductile damage parameters identification of materiál used for nuclear parts construction under quasi-static and dynamic loading condition in the temperature range 20 -400 °C. Based on the experience and extensive literature survey the design of suitable test specimen was performed. Final design of each test specimen was evaluated by the numerical simulation. Identification of ductile damage parameters will be performed on a set of tests specimen including round tensile with different notch radii, flat tensile specimen, butterfly specimen, miniature tensile bars and small punch test samples. The damage process itself is evaluated based on the equivalent plastic strain which represents acumulated plastic deformation in the materiál at the moment of the fracture. The calibration experiment is performed with as constant as possible values of triaxiality, Lode parametr, temperature and strain rate. The evaluation of mentioned parametrs is performed on samples using clasical means as extensometer and load cell in combination with high speed camera, video-extensometr and DIC ( Digital Image Correlation). The loading of the special type of sampes is performed using custom - made testing devices as BUTTERFLY , NAKAZIMA or BIAXIAL The meassured values on used samples will be further evaluated using FEM solver ABAQUS. The calibration of the plastic response curve and identification of the damage initiation criteria will be based on the optimization script algorithm developed on CVUT. The output will be ductile damage parametrs which could be directly used in ABAQUS environment for numeriacl solution of the nuclear parts. Further subroutines will be elaborated to include more sophisticated damage models.

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