Plastic strain gradients and transient fatigue crack growth: A computational study. (March 2019)

• Record Type: Journal Article
• Authors: Pribe, Joshua D.; Siegmund, Thomas; Tomar, Vikas; Kruzic, Jamie J.
• Is Part Of: International journal of fatigue. Volume 120(2019)
• Page Start: 283
• Page End: 293
• Publication Date: 2019-03
• Subjects: Fatigue crack growth -- Plasticity -- Crack closure -- Overloads -- Damage accumulation; Materials -- Fatigue -- Periodicals; Materials -- Fatigue; Periodicals; 620.1122
• DOI: 10.1016/j.ijfatigue.2018.11.020
• Languages: English
• ISSNs: 0142-1123

Abstract

Graphical abstract: Highlights: Plastic strain gradients restrict crack-tip plasticity during an overload. Restricted plastic deformation enhances post-overload crack growth rates. Plastic strain gradients are key in the evolution of post-overload crack closure. Plastic strain gradients do not affect steady-state fatigue crack growth rates. Abstract: Fatigue crack growth is analyzed for steady state and overload conditions. The model combines an elastic-plastic strain gradient hardening material and an irreversible cohesive zone model. Plastic strain gradients are found not to affect steady-state fatigue crack growth but play a key role in the overload response. Plastic strain gradient hardening lowers plastic strain magnitudes and alters the spatial distribution of plastic strain. This leads to reduced crack closure and higher crack growth rates during and after the overload. Using classical plasticity alone to describe fatigue crack growth following an overload is thus nonconservative.