Fatigue Precracking Time Estimates for Three-Point Bending Specimens

2019-10-01
Ghasabi, A. Alipour
Motameni, A
Kadıoğlu, Fevzi Suat
Specimens containing sharp cracks are needed in certain types of mechanical tests, first and foremost for fracture toughness measurement of materials. Their use, however, is not just limited to this type of test. Another category of experiments deals with characterizing nonlinear vibrations of beams containing breathing cracks. To produce cracked beam specimens, fatigue cracks can be grown ahead of sharp notches under controlled loading. ASTM E399 and ASTM E1820 standards provide guidance on such procedures for preparation of fracture toughness test specimens. However, certain issues which might become important in testing of vibrations of cracked beams, such as the time required for specimen preparation is not addressed in these standards. In this article, both low cycle fatigue methods and linear elastic fracture mechanics methods are used to estimate the number of loading cycles required to have a crack of desired length at the notch tip. Calculation results are compared with experimental ones, and the effects of various factors influencing the required number of loading cycles for a certain crack size are discussed.
JOURNAL OF FAILURE ANALYSIS AND PREVENTION

Suggestions

Corrosion Resistance Studies of Austenitic Stainless Steel Grades in Molten Zinc-Aluminum Alloy Galvanizing Bath
Loto, Roland Tolulope; Ozcan, Emre (Springer Science and Business Media LLC, 2016-06-01)
The corrosion inhibition performance and mechanical behavior of galvanized and heat-treated four newly developed austenitic stainless steel grades and type 316L austenitic stainless steel for application as sink rolls in galvanizing baths of 0.14-0.21 wt.% aluminum was investigated and compared through immersion corrosion test to determine the weight loss between 168 and 504 h, tensile test, and Charpy impact test. The delta ferrite content of the test samples was observed and estimated through optical micr...
CRACK-GROWTH KINETICS OF 7050-T73651 ALUMINUM-ALLOY UNDER CONSTANT LOAD AT 150-DEGREES-C
SARIOGLU, F; ABACHI, P; DORUK, M (Springer Science and Business Media LLC, 1993-03-15)
Crack growth tests at 150-degrees-C under constant load conditions were performed on compact tension specimens of 7050-T73651 aluminium alloy. The d.c. potential drop method was employed to monitor crack lengths throughout the tests. Fracture mechanics parameters such as the stress intensity factor (K) and energy-rate line integral (C*) were used to establish correlation with the crack propagation rates. As a result of experiments it was found that crack growth rates (da/dt) versus K, over discrete ranges o...
Impact essential work of fracture toughness of ABS/polyamide-6 blends compatibilized with olefin based copolymers
Ozkoc, Guralp; Bayram, Göknur; Bayramli, Erdal (Springer Science and Business Media LLC, 2008-04-01)
The impact fracture toughness of acrylonitrile-styrene-butadiene/polyamide-6 (ABS/PA6) blends compatibilized with 5% by weight carbon monoxide modified ethylene-n butyl acrylate-maleic anhydride (EnBACO-MAH) or ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) copolymers were examined as a function of blend ratio by standard Charpy tests, Essential Work of Fracture (EWF) Methodology and fracture surface morphologies. The samples were first processed in twin-screw extruder and they were subsequently i...
Stress intensity factor and compliance solutions for a single edge notched specimen with clamped ends
Blatt, Drew; John, Reji; Çöker, Demirkan (Elsevier BV, 1994-01-01)
A single edge notched geometry [SE(T)] with clamped ends is well suited for fracture toughness and fatigue crack growth testing of composites. Closed form expressions for the stress intensity factor and the compliance for an SE(T) with clamped ends were developed using finite element analysis. Using these expressions, automated crack growth tests were conducted on a monolithic Ti-1100 and a [90]8 SCS-6/Ti-24Al-l 1Nb composite. The crack growth behavior, characterized in terms of the crack growth rate versus...
Mixed-mode fracture analysis of orthotropic functionally graded materials under mechanical and thermal loads
Dağ, Serkan; Sarikaya, Duygu (Elsevier BV, 2007-12-01)
Mixed-mode fracture problems of orthotropic functionally graded materials (FGMs) are examined under mechanical and thermal loading conditions. In the case of mechanical loading, an embedded crack in an orthotropic FGM layer is considered. The crack is assumed to be loaded by arbitrary normal and shear tractions that are applied to its surfaces. An analytical solution based on the singular integral equations and a numerical approach based on the enriched finite elements are developed to evaluate the mixed-mo...
Citation Formats
A. A. Ghasabi, A. Motameni, and F. S. Kadıoğlu, “Fatigue Precracking Time Estimates for Three-Point Bending Specimens,” JOURNAL OF FAILURE ANALYSIS AND PREVENTION, pp. 1275–1285, 2019, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/35140.