Showing papers in "International Journal of Fatigue in 1985"

TL;DR: In this paper, the authors investigate the mixed mode fatigue crack growth threshold behavior of mild steel and show that the expected tendency to Mode I crack growth showed as an initial directional discontinuity followed by a smooth rotation of the crack front until it was almost perpendicular to the specimen sides.

TL;DR: In this article, a CMnSi dual-phase steel has been heat-treated to yield three different microstructures, i.e., a dispersion of martensite in fine-grained ferrite (Type I), a continuous network of Martensite around ferrite grains (Type II) and martensites islands encapsulated in a ferrite matrix (Type III), and low cycle fatigue tests have been conducted.

TL;DR: In this paper, a theoretical method for determining random load fatigue damage on offshore platforms is proposed, based on a rainflow analysis of the dynamic response of individual members to various sea states.

TL;DR: In this article, the effect of tensile and compressive overloads on the threshold stress intensity level and crack closure behavior of one aluminium alloy and three steels has been investigated, and it was shown that an initially decreased and then increased opening stress was mostly responsible for the delayed retardation and crack arrest.

TL;DR: In this paper, the authors compared different methods of measuring crack closure and found that the commonly employed notchmouth clip-gauge method is not sensitive enough to detect the closure of short cracks in regions of notch plasticity.

TL;DR: In this paper, a 20% fall in the saturation stress in tension and cusp formation in the compressive portion of the cycle have been identified as the two best criteria for defining the failure life of laboratory specimens in strain-controlled low cycle fatigue testing.

TL;DR: In this paper, a direct current potential difference technique was used for the continuous measurement of crack dimensions in spot-welded mild steel specimens under fatigue loadings, and initial results indicate that macrocrack propagation is the dominant fatigue mechanism for specimens with lives of the order 2 × 10 6 cycles.

TL;DR: In this paper, the authors test the hypothesis that fatigue cracks in drawn, pearlitic steel wire propagate from pre-existing surface defects which can be treated as cracks, and the fatigue limits of five different wires have been statistically determined.

TL;DR: In this article, the fatigue strength of dual-phase steel was found to be similar to that of other types of steel ( eg solution hardened or microalloyed steels) of equal tensile strength.

TL;DR: In this article, the authors analyzed the hysteresis loop shape, stress/strain response and plastic strain energy as a function of applied cycles for different microstructures.

TL;DR: In this article, the stress intensity at the deepest point of sickle-shaped cracks is calculated for a constant, a linear and a quadratic locally varying stress distribution by use of a weight function derived from finite element results.

TL;DR: In this paper, two significantly different microstructures - polygonal ferrite grains of average grain size 10-120 μm and acicular ferrite/upper bainite colonies of dimensions 200-625 μm -were examined in order to determine the influence of each on cyclic strain hardening and related properties.

TL;DR: In this paper, the average fatigue crack growth rates of ABS EH36 steel under spectrum loading intended to simulate sea loading of offshore structures in the North Sea was studied using fracture mechanics.

TL;DR: In this article, a procedure for estimating the useful life of a component for a given (admissable) probability of fatigue fracture origination under random loading is presented, using material constants obtained from the S/N and cyclic stress/strain curves, standard deviation and probability density distribution of the loading process and a macroblock of harmonic cycles obtained by applying the rainflow cycle counting method to the random loading process.

TL;DR: In this article, the performance of lapped, welded and mechanical connections are summarized and related to continuous bars and to class D for BS5400 for highway bridges, and three types of structural connection are reviewed: high strength bolted connections between plates, shear connectors between steel and concrete, and epoxy resin bonding between steel-and concrete.

TL;DR: In this paper, the effects of omitting low-amplitude cycles from the gust-dominated TWIST load sequence (MiniTWIST) and the removal of small load ranges from the manoeuvre-dominated FALSTAFF load sequence were investigated.

TL;DR: In this paper, the authors developed a system for computer-controlled crack propagation testing under random load sequences, which includes the capability to simulate any desired K-function on standard laboratory specimens and continuous on-line rainflow analysis of the test load sequence to exclude cycles falling below given values of threshold stress intensity, stress level or range.

TL;DR: In this paper, the development of a fully automated test apparatus for near-threshold fatigue crack growth rate measurements in a liquid helium environment is described, and some initial results for AISI 300 series stainless steels are presented.

TL;DR: In this paper, a model was derived to predict the true threshold value for fatigue crack growth in the absence of crack closure, based only on the tensile and cyclic properties of the material, was successfully verified against a set of experimental data on medium and high strength steels and one aluminium alloy.

TL;DR: In this article, the fracture mode transition for two steels fatigued in air and seawater was investigated by measuring the crack growth rates and by examining the fractured surfaces using scanning electron microscopy.

TL;DR: Torsional fatigue tests have been carried out on overaged and hydrogen charged specimens of 2024 aluminium in gaseous hydrogen and humid air, and they found that hydrogen charging significantly increased the number of fatigue crack initiation sites compared with uncharged specimens tested in argon as mentioned in this paper.

TL;DR: In this paper, the fatigue crack initiation and propagation in plain and notched specimens of titanium IMI 550 alloy with different percentages of transformed β-phase has been investigated, and the results showed that the S/N curves for plain specimens having a two-phase α/β microstructure were superior to those having a 100% transformed β micro-structure.

TL;DR: In this article, it was found that when the specimen life exceeds 106 cycles, the temperature of the specimen stabilizes, however, if the temperature does not reach equilibrium with the testing temperature, the sample life is short (4 cycles).

TL;DR: In this paper, a three-step model of fatigue crack formation at holes is proposed and it is concluded that a crack detected at a hole has a high probability of taking longer to grow to failure than predicted by fracture mechanics analysis.

TL;DR: In this article, a method to estimate the strength reduction factors (K f ) of notched fatigue specimens is presented, where the influence of the notch geometry on fatigue life can be assessed by photoelastic analysis.