Journal ArticleDOI
Material damping in 6061-T6511 aluminium to assess fatigue damage
Mehmet Colakoglu,K. L. Jerina +1 more
TLDR
In this article, the effects of fatigue on damping factor were studied for 6061-T6511 aluminium alloy and the experiments showed that the damping energy changes with the number of fatigue cycles.Abstract:
Studies in fatigue can be summarized into two stages, fatigue crack initiation and crack propagation. Fatigue damage may increase the risk of failure under cyclic load. Energy dissipation, termed damping, occurs in engineering metals and is a function of the cyclic loading history. Damping behaviour of materials has been estimated using many different experimental techniques, and parameters i.e. the loss factor vs. strain amplitude, frequency range, etc. However, micro-structural changes in the form of fatigue damage are also contributors to damping in engineering materials. In order to measure energy dissipation, a damping monitoring method has been used. Under a constant cyclic load up to the point of fatigue crack initiation, the effects of fatigue on damping factor were studied for 6061-T6511 aluminium alloy. In the experiments, the stress levels were below yield point, 50% and 70% of ultimate strength. Experimental results showed that the damping factor changes with the number of fatigue cycles. Percentage increase in damping energy was calculated using experimental data.read more
Citations
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Journal ArticleDOI
Nonlinear ultrasonics for in situ damage detection during high frequency fatigue
TL;DR: In this article, the authors reported the use of the feedback signal of an ultrasonic fatigue system to dynamically deduce fatigue damage accumulation via changes in the nonlinear ultrasonic parameter.
Journal ArticleDOI
Uninterrupted and accelerated vibrational fatigue testing with simultaneous monitoring of the natural frequency and damping
TL;DR: In this paper, an improved fatigue-testing methodology based on the dynamic response of the test specimen to the harmonic excitation in the near-resonant area with simultaneous monitoring of the modal parameters is presented.
Journal ArticleDOI
An Unifying Approach to assess the structural strength
TL;DR: In this paper, the authors define a new approach unifying the different failure modes of a structure and define a measure of damping, a material property able to correlate vibration parameters with high cycle fatigue and related to the damage of materials and structures.
Journal Article
Factors effecting internal damping in aluminum
TL;DR: In this article, seven different environmental factors and their effects on the damping are analyzed in the case of 6061 aluminum alloy, and the relationship between the external damping and every single effective factor is complex and vary depending on the aluminum type.
Journal ArticleDOI
Fatigue damage model based on the natural frequency changes for spot-welded joints
TL;DR: In this article, the variation of natural frequency during crack propagation process was investigated for single-spot and double-spots tensile-shear spot-welded specimens.
References
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Journal ArticleDOI
The effect of pitting corrosion on fatigue life
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Journal ArticleDOI
The effect of porosity on the microstructural damping response of 6061 aluminium alloy
TL;DR: In this article, the effects of micrometre-sized pores on the damping response of 6061 aluminium alloy were investigated using free vibration decay and resonant vibration techniques.
Journal ArticleDOI
The stress–life fatigue behaviour of aluminium alloy foams
McCullough,Fleck +1 more
TL;DR: In this article, the tension-tension and compression-compression nominal stress versus fatigue life responses of Alulight closed cell aluminium alloy foams have been measured for the compositions Al−1Mg-0.6Si and Al− 1Mg−10Si, and for relative densities in the range 0.1−0.4.
Journal ArticleDOI
Internal friction of foamed aluminium in the range of acoustic frequencies
TL;DR: In this paper, the internal friction of aluminium foams with various porosities was measured in the range of acoustic frequencies over a wide strain-amplitude range by the bending-vibration method.
Journal ArticleDOI
Estimation of damping from response spectra
TL;DR: In this article, the bias errors of the damping ratio estimates are a function of the true damping of the system and the ratio of analysis bandwidth to resonant frequency, and the bias error for the half-power bandwidth method is three times that for the peak response method.