Techno Press
Techno Press

Structural Engineering and Mechanics   Volume 42, Number 2, April25 2012, pages 153-174
DOI: http://dx.doi.org/10.12989/sem.2012.42.2.153
 
Parameter calibrations and application of micromechanical fracture models of structural steels
Fangfang Liao, Wei Wang and Yiyi Chen

 
Abstract     [Full Text]
    Micromechanical facture models can be used to predict ductile fracture in steel structures. In order to calibrate the parameters in the micromechanical models for the largely used Q345 steel in China, uniaxial tensile tests, smooth notched tensile tests, cyclic notched bar tests, scanning electron microscope tests and finite element analyses were conducted in this paper. The test specimens were made from base metal, deposit metal and heat affected zone of Q345 steel to investigate crack initiation in welded steel connections. The calibrated parameters for the three different locations of Q345 steel were compared with that of the other seven varieties of structural steels. It indicates that the toughness index parameters in the stress modified critical strain (SMCS) model and the void growth model (VGM) are connected with ductility of the material but have no correlation with the yield strength, ultimate strength or the ratio of ultimate strength to yield strength. While the damage degraded parameters in the degraded significant plastic strain (DSPS) model and the cyclic void growth model (CVGM) and the characteristic length parameter are irrelevant with any properties of the material. The results of this paper can be applied to predict ductile fracture in welded steel connections.
 
Key Words
    ductile fracture; micromechanical fracture model; parameter calibration; ultra low cycle fatigue; structural steel
 
Address
Fangfang Liao: Department of Structural Engineering, Tongji University, Shanghai 200092, China
Wei Wang: Department of Structural Engineering, Tongji University, Shanghai 200092, China; State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, ChinaYiyi Chen: Department of Structural Engineering, Tongji University, Shanghai 200092, China; State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, China
 

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