Cyclic behaviour of materials

Miller, K. J.

doi:10.1243/03093247v053185

Cited by 27 publications

(8 citation statements)

References 15 publications

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“…According to [7,82,86,88], one can judge belonging of a given metal or alloy to cyclically hardening, softening, or stable ones from the ratio of the ultimate strength σ u to the yield stress σ 0 2 . .…”

Section: Results Of Studying Inelasticitymentioning

confidence: 99%

Nonlocalized Fatigue Damage of Metals and Alloys. Part 1. Inelasticity, Investigation Methods, and Results

Troshchenko

2005

Strength Mater

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Analysis of data presented in the literature and results of unique studies revealed that nonlocalized fatigue damage of metals and alloys, which manifests itself in the initiation and propagation of a large number of microcracks distributed arbitrarily in the bulk of the material, can be considered with the use of the characteristics of inelastic deformation such as inelastic strain and inelastic strain energy per cycle. The author studied the nature of the material inelasticity and methods of its investigation. Analysis has been made of the hysteresis loop shape, width, and area, as well as of the main regularities of inelastic deformation of metals and alloys.Keywords: nonlocalized fatigue damage, inelastic strain, inelastic strain energy.Introduction. The process of fatigue of metals and alloys can be divided into two stages: the stage of nonlocalized fatigue damage and that of localized fatigue damage where the process of fatigue is defined by the propagation of the dominant crack that leads to final fracture.As numerous investigations showed, the stage of the fatigue crack initiation is longer lasting than the stage of its propagation. Figure 1 shows the results of generalization of some of those investigations performed in [1], which are presented in the form of the relation between the ratio of the number of cycles to the initiation of a fatigue crack of length about 0.05 mm under axial loading of smooth specimens from various materials to the number of cycles to fracture and the number of cycles to fracture.It is seen that under high-cycle fatigue, which corresponds to the number of cycles to fracture equal to 10 5 and more, the stage of the fatigue crack initiation accounts for more than 90% of the total number of cycles to fracture.In the case of the fatigue fracture in the presence of stress concentration, fretting, etc., the stage of crack initiation is of shorter duration, yet it remains dominating.The size of a fatigue crack corresponding to the transition from the stage of nonlocalized to the stage of localized fatigue damage depends on the material structure, the level of acting stresses, loading regime, stress state type, and other factors. The size of such a crack generally decreases with increasing strength of the alloy and increases in torsion as compared with tension-compression [2,3].Thus, in [3] for steel 45 (σ u = 516 MPa) it is shown that, at stresses equal to the fatigue limit for the test duration 10 7 cycles, the size of the maximum crack in tension-compression and in torsion is 0.05 and 0.17 mm, respectively, and for 12KhN3A steel of higher strength (σ u = 950 MPa), it is 0.03 and 0.08, respectively. These crack dimensions are close to those used for plotting the relation in Fig. 1.

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Section: Results Of Studying Inelasticitymentioning

confidence: 99%

Nonlocalized Fatigue Damage of Metals and Alloys. Part 1. Inelasticity, Investigation Methods, and Results

Troshchenko

2005

Strength Mater

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“…In a later study, Topper and Biggs [33] used the strain-based LDR to correlate their experimental results. However, due to the inherent deficiencies of the LDR, no matter which version is used, life prediction based on this rule is oflen found to he unsatisfactory [34]. Experimental evidence under completely reversed loading condition often indicates that D > I for a low-to-high (L-H) loading sequence, and D < 1 for a high-to-low (H-L) loading sequence for metals.…”

Section: -Pomentioning

confidence: 99%

Modeling fatigue behavior of electronically conductive adhesive joints under elevated temperature and humidity conditions

Gomatam¹,

Sancaktar²

4th IEEE International Conference on Polymers and Adhesives in Microelectronics and Photonics, 2004. POLYTRONIC 2004.

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This paper describes a novel fatiguelife prediction methodology aimed at providing the design engineer an easy fatigue life predictive tool using experimental data, for both cumulative fatigue damage, as well as constant loading fatigue conditions. This encompasses an integrated approach to joint testing, analysis, and modeling. Utilizing the proposed methodologies, we aim to predict the changes in fatigue life of the adhesive, based on the whole spectrum of test variables including temperature, humidity, stress ratio, preconditioning (variable stress ratios), and frequency. This modeling approach is expected to give the design engineer an initial assessment tool for the effects of detrimental fatigue conditions, eventually leading to a much improved fatigue life, improved fail-safe capability, and reduced manufacturing costs.

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“…Miller [25] and Landgraf [26] review much that is relevant. Under repeated loading, cyclic softening or hardening prevents the derivation of a unique stress/strain curve.…”

Section: E F F K T Of Stress Hiaxiality Oti Cyclic Stresslstrain Hehamentioning

confidence: 99%

“…In the last 20 years or so much work has been published on the cyclic stress/strain behaviour of materials subject to high strain uniaxial loading. Miller [25] and Landgraf [26] review much that is relevant. Under repeated loading, cyclic softening or hardening prevents the derivation of a unique stress/strain curve.…”

Section: E F F K T Of Stress Hiaxiality Oti Cyclic Stresslstrain Hehamentioning

confidence: 99%

The Behaviour of Fatigue Cracks Subject to Applied Biaxial Stress: A Review of Experimental Evidence

Smith

Pascoe

1983

Fatigue Fract Eng Mat Struct

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Experimental studies aimed at understanding the fatigue process in metals and polymers have usually been performed under uniaxial stress. Only in the last two decades or so has much experimentation been carried out on fatigue crack propagation under biaxial stress. This paper reviews the available published data. Crack propagation behaviour under biaxial stress is dictated by 3 parameters: stress biaxiality itself, which is defined here as the ratio of the in-plane principal stresses, crack angle with respect to the applied principal stress directions and stress intensity factor range. Depending on the first two parameters. cracks may grow in Mode I, Mode 11 or Mixed-Mode. Crack growth data have been presented using these three divisions. Two short sections have been included on initiation and cyclic stress/strain behaviour under biaxial stress to emphasise the fact that crack growth cannot be fully understood without knowing something of them. The accumulated data do not lead to adequate conclusions on either the qualitative or quantitative behaviour of cracks subject to cyclic in-plane biaxial stress. Reasons for the confusion and even contradiction of independent results are put forward and some discussion given to the possible directions of future experimental work.

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Cyclic behaviour of materials

Cited by 27 publications

References 15 publications

Nonlocalized Fatigue Damage of Metals and Alloys. Part 1. Inelasticity, Investigation Methods, and Results

Nonlocalized Fatigue Damage of Metals and Alloys. Part 1. Inelasticity, Investigation Methods, and Results

Modeling fatigue behavior of electronically conductive adhesive joints under elevated temperature and humidity conditions

The Behaviour of Fatigue Cracks Subject to Applied Biaxial Stress: A Review of Experimental Evidence

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