The Influence of the Out-of-Plane Constraint on Fracture Toughness of High Strength Steel at Low Temperatures

Abstract

The values of JIC measured in laboratories, when used in practical applications, may lead to conservative results in assessing the critical state of a structural element. When the thickness of the structural element is less than required by standards the fracture toughness can be much higher than measured in the laboratory. In this paper the fracture toughness of brittle or semi-brittle materials is discussed. The out-of-plane constraint is characterized in this paper by other quantity then the specimen thickness. This quantity can be related to the thickness if the thickness is uniquely defined.

Strength and Fracture Toughness of Hardox-400 Steel

“…In a few publications, the results of fracture toughness test of high-strength steels (HSS) have been presented [14][15][16][17][18][19][20][21]. Lack of accurate information on the fracture toughness of HSS does not allow to properly assess the strength of structural elements made of these steels and assess the parameters of their safe use [22].…”

“…This paper presents a review of the results which were obtained in testing of high-strength steels: S960QC and Hardox-400 since 2009. Several papers published in this time period have reported the results obtained during investigation of these steels [16][17][18][19][20][21]. However, during next testing, the results were complemented and more exact.…”

The influence of the out-of- and in-plane constraint on fracture toughness of high strength steel in the ductile to brittle transition temperature range

“…Force-deflection curves. They demonstrate (different onset of the crack jump) why there is a large scatter of the J IC values observed [4]. …”

“…Thus, in the next section, the measures of the stress triaxiality are defined, and, in the following sections, they are applied to the analysis of the out-of-plane constraint influence on the fracture toughness. Some of the results in Chapter 2 were presented in the conference proceedings [4] 2.1. TRIAXIALITY PARAMETERS The triaxiality factors, which are most often found in fracture mechanics literature, can be stated as follows:…”

The FEM Analysis of Stress Distribution in front of the Crack Tip and Fracture Process in the Elements of Modified and Unmodified Cast Steel G17CrMo5-5

“…The parameters Tz (Guo, 1993) and 3R (Rice and Tracey, 1969) are used in fracture mechanics to evaluate the triaxiality stress state level. The weighted average value of Tz -Tm, and the weighted average value of 3R -3Rm were proposed to evaluate the triaxiality stress state in the paper (Neimitz et al, 2015). These parameters take into account the specimen thickness.…”