Relating Charpy energy to fracture toughness in the lower transition region using a Weibull stress dependent energy scaling model. (September 2018)

• Record Type: Journal Article
• Authors: Smith, R.J.; Horn, A.J.; Sherry, A.H.
• Is Part Of: International journal of pressure vessels and piping. Volume 166(2018)
• Page Start: 72
• Page End: 83
• Publication Date: 2018-09
• Subjects: Charpy V-notch impact test -- Weibull stress -- Fracture toughness -- Cleavage fracture -- Weakest-link statistics -- Constraint; Pressure vessels -- Periodicals; Pipe -- Periodicals; Récipients sous pression -- Périodiques; Tuyaux -- Périodiques; Pipe; Pressure vessels; Periodicals; 681.76041
• DOI: 10.1016/j.ijpvp.2018.06.001
• Languages: English
• ISSNs: 0308-0161

Abstract

Abstract: Accurate prediction of fracture toughness from Charpy energy is challenging due to the differences between fracture toughness tests and Charpy tests, such as geometry (deep sharp crack vs. shallow blunt V-notch) and loading rate (quasi-static vs. dynamic). This paper uses experimental and numerical approaches to investigate whether the Weibull stress can be used to scale Charpy energy to fracture toughness in the lower transition region. A Weibull-stress based energy scaling model is proposed which is shown to accurately predict cleavage fracture at quasi-static loading rates. An extension of the energy scaling approach to dynamic loading conditions indicates that the Weibull modulus is independent of strain rate, and that quasi-statically derived moduli can be used to predict fracture toughness from a dynamically tested Charpy specimen. The paper concludes that the proposed energy scaling approach, and its extension to dynamic loading conditions, provides a suitable basis for relating Charpy energy to fracture toughness in the lower transition region. Highlights: Difference between Charpy and toughness mainly geometrical, strain rate secondary. Modified Weibull parameter calibration method proposed using Energy Scaling Model. Energy Scaling Model then extended to cover both static and dynamic loading. Weibull modulus shown to be broadly independent of strain rate. Energy Scaling Model suitable for relating Charpy energy to fracture toughness.