The Neuber relation is widely used to compute elastoplastic stresses and strains at stress concentrations, but a newer relation has been developed by Glinka. Prediction of local strain response is important because low cycle, fatigue life models are based on the strain range. The effects of notch root constraint on the response have been difficult to predict or measure. This paper evaluates the abilities of six models of notch root behavior by comparing them with experimental results over a range of constraints. The models are: the Neuber model, the Neuber model as modified by Walker, the Glinka models for plane stress and for plane strain, and two modifications of the Glinka models that are presented in this paper. Comparisons are made with strains measured at the roots of notches by resistance gages or by laser-based interferometry; data come from previous works as well as some new results of the authors. The constraints vary from plane stress to plane strain with several intermediate cases. Conclusions must take into account the fact that elastoplastic strain measurements have scatter arising from the gage length relative to the grain size. But, in general, one can say that the Neuber model is best for plane stress and the Glinka plane-strain model is best for very large constraint. Response for intermediate amounts of constraint are predicted better by one of the other models.

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This paper examines the effects of loading rate on the Weibull stress model for prediction of cleavage fracture in a low‐strength, A515‐70 pressure vessel steel. Interest focuses on low‐to‐moderate loading rates (K˙I < 2500 MPa √m s−1 ). Shallow cracked SE(B) specimens were tested at four different loading rates for comparison with previous quasi‐static tests on shallow notch SE(B)s and standard C(T)s. To utilize these dynamic experimental data, we assume that the Weibull modulus (m) previously calibrated using quasi‐static data remains invariant over the loading rates of interest. The effects of dynamic loading on the Weibull stress model enter through the rate‐sensitive material flow properties, the scale parameter (σu ) and the threshold Weibull stress (σw‐min ). Rate‐sensitive flow properties are modelled using a viscoplastic constitutive model with uniaxial, tension stress–plastic strain curves specified at varying plastic strain rates. The analyses examine dependencies of σw‐min and σu on K˙I . Present results indicate that σw‐min and σu are weak functions of loading rate K˙I for this pressure vessel steel. However, the predicted cumulative probability for cleavage exhibits a strong sensitivity to σu and, consequently, the dependency of σu on K˙I is sufficient to preclude use of the static σu value for high loading rates.