Simulation of hydrogen assisted-cracking in terms of its growth phenomenon

• Cracks in dangerous structure components.
• Specific formula to define the fracture process zone length.
• High-strength steel AISI 4340.
• Tool to estimate the durability of the structure components under consideration.

Hydrogen-assisted cracking is a nagging problem to take place in various structures like high-strength bolts and steam generator tubes. Here, specific model to describe crack propagation in structure components under cycling and hydrogen environment influence based on the two-parameter hydrogen assisted cracking criterion is presented. The proposed criterion includes the hydrogen concentration in the fracture process zone in the vicinity of the crack tip as well as critical stress intensity factor. The current hydrogen concentration in environment is related to the maximum solubility of the hydrogen in material. In addition the specific expression to define the fracture process zone length is proposed. The developed model allows estimating a durability of structure components under cycling loading and hydrogen environment influence.