Study on the Size Dependence of Calibration Parameters of the New Local Approach Model for Cleavage Fracture
- PDF / 711,535 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 64 Downloads / 245 Views
y on the Size Dependence of Calibration Parameters of the New Local Approach Model for Cleavage Fracture A. R. Shen1, P. C. Li1*, Z. S. Yu2, G. A. Qian3**, F. Berto4, and W. Wu5*** 1
School of Mechanical and Automotive Engineering, Shanghai University of Engineering Science, Shanghai, 201620 China 2 School of Materials Engineering, Shanghai University of Engineering Science, Shanghai, 201620 China 3 State Key Laboratory for Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing, 100190 China 4 Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology, Trondheim, 7491 Norway 5 Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing, 100081 China * e-mail: [email protected] ** e-mail: [email protected] *** e-mail: [email protected] Received July 22, 2019, revised July 22, 2019, accepted July 31, 2019
Abstract—This paper investigates whether the Weibull parameters of the new local approach model for cleavage fractures are affected by the geometric size of the specimen. Based on the fracture test data of A508-C steel, low temperature round notched bar tensile specimens of A508-C steel with two different notch sizes are numerically simulated by using finite element analysis software ABAQUS, and the stress distributions are obtained. The Weibull parameters of two notched bars are calibrated by linear regression method. The results show that the Weibull parameters of the specimens with different notch sizes are different. This suggests that the calibration parameters are dependent on the notch size. Keywords: cleavage fracture, new local approach model, Weibull parameters, notch size DOI: 10.1134/S1029959920040062
NOMENCLATURE dV — differential volume, mm3; E — Young’s modulus, MPa; F — external load, kN; i — the serial number of the specimen; m — Weibull modulus; N — total number of the specimen; P — probability of cleavage fracture; P(i) — prescribed probability for the ith specimen; r — notch radius, mm; V0 — mean volume occupied by each microcrack in a solid, mm3; Vpl — plastic volume, mm3; — Poisson’s ratio; 0 — Weibull scale parameter, MPa; 1 — maximum tensile principal stress, MPa; 1,0 — value of 1 at initial yield of a differential volume element dV, MPa; vM — von Mises stress, MPa; W — Weibull stress, MPa;
W,new — newly defined Weibull stress, MPa; ys — yield stress, MPa. 1. INTRODUCTION Cleavage fracture [1] is a kind of brittle fracture, which is the most dangerous form of fracture and often leads to disastrous failure in engineering applications [2], such as the brittle fracture of reactor pressure vessels [3]. Therefore, cleavage fracture has been the focus of research from many researchers in recent years [e.g., 4–7]. Cleavage fracture consists of three nonstop successive stages: nucleation of a crack in a second-phase particle; the second phase particle-sized crack propagates across the particle and grain boundary; grain-sized crack extends through grain boundary into contiguous grains [8,
Data Loading...
