Topic
Vibration fatigue
About: Vibration fatigue is a research topic. Over the lifetime, 3460 publications have been published within this topic receiving 46297 citations.
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TL;DR: In this paper, the influence of modal parameter changes that occur during the experimental fatigue test, on the correctness of the numerical fatigue life prediction was determined, and a validated numerical model of the specimen was obtained for the case of the random-vibration base excitation.
Abstract: The presented study experimentally and theoretically researches vibrational fatigue of an aluminum-alloy specimen for harmonic and random loads. The main aim of this study is to determine the influence of modal parameter changes that occur during the experimental fatigue test, on the correctness of the numerical fatigue life prediction. Firstly, the material’s fatigue parameters were obtained with harmonic base excitation of the specimen near its natural frequency. During the harmonic fatigue testing the changes in the specimen’s natural frequency and damping loss factor were monitored as the fatigue damage was accumulated at the fatigue zone. Secondly, with a validated numerical model of the specimen the stress transmissibility was obtained for the case of the random-vibration base excitation. Finally, by respecting the stress response along with the experimentally obtained material fatigue parameters the vibration fatigue life was estimated for the case of the random vibration load. The numerically predicted fatigue life was compared to the experimental results, obtained with the electro-dynamic shaker. From this comparison the influence of the damping-loss-factor changes on the calculated fatigue life was clearly shown. For the case of the observed specimen, the damping loss factor included in the fatigue life estimation should be increased by more than 100 percent to give reliable prediction of the fatigue life. The presented research shows new possibilities and critical aspects in the area of accurate high-cycle vibration fatigue life-estimation of dynamic structures.
20 citations
TL;DR: In this paper, a vibrational fatigue bench composed of an electrodynamic shaker and a closed loop vibration control system is used to measure the strain versus cycle number to failure of low carbon steel under vibratory testing.
20 citations
TL;DR: In this paper, a non-contacting measurement method was proposed that is based on optical displacement sensors using light emission diodes (LEDs) to measure the vibration stress.
20 citations
01 Jan 2010
TL;DR: In this article, a nonlinear cyclic cyclic riser-soil interaction behavior was used to determine the contribution of different loading parameters on fatigue damage of steel catenary risers in the TDA in deep water soft sediments, where the main loading parameters considered are: different motions of floating vessels, wave heights, wave periods and wave packs ordering.
Abstract: Steel catenary risers (SCRs) are often the preferred option for subsea tie-back to floating platforms in deep water due to their conceptual simplicity, ease of construction and installation and simple interface with the flowlines Fatigue design of SCRs, particularly in the touch down area (TDA), has always been one of the major engineering challenges Traditionally, fatigue assessment of SCRs has usually been highly conservative, because of lack of precise understanding of the non-linear soil-riser-interaction in the TDA Most fatigue studies are based on assumed linear stiffness for the seabed, partly because of the lack of robust non-linear riser-seabed interaction models and partly because the linear response simplifies the fatigue study The recent availability of non-linear seabed response models provides an opportunity to improve fatigue assessment, but it is first necessary to evaluate how best to conduct fatigue studies for such nonlinear systems which can be sensitive to wide range of input parameters This paper outlines a new advanced numerical model, considering nonlinear cyclic riser-soil interaction behavior, used to determine the contribution of different loading parameters on fatigue damage of SCRs in the TDA in deep water soft sediments The main loading parameters considered are: different motions of floating vessels, wave heights, wave periods and wave packs ordering Numerical modeling has shown that over 95% of the fatigue damage corresponds to floating vessel motion parallel to the riser axis at the connection point to the vessel It is also shown that riser response at TDA is highly influenced with amplitude and period of the environmental loadingsCopyright © 2010 by ASME
20 citations
TL;DR: In this article, the difference in predicting fatigue failure between sequentially applied uniaxial and simultaneous triaxial tests is explored, with the goal of more closely approximating real-world operating conditions.
Abstract: Validating the design and reliability of equipment prior to fielding is a critical step in the materiel development and manufacturing process. Success requires that the new equipment undergo and survive testing. Stress screen vibration testing determines the equipment's design capability. Traditionally, stress screen vibration tests have been conducted by sequentially applying uniaxial excitation to test articles along three orthogonal axes. Simultaneous multiaxial excitation is an advanced method of vibration testing with the goal of more closely approximating real-world operating conditions. Multiaxial testing achieves the synergistic effect of exciting all modes simultaneously and induces a more realistic vibrational stress loading condition. This research begins an effort to explore the difference in predicting fatigue failure between sequentially applied uniaxial and simultaneous triaxial tests. The research plan starts with simple cantilever beam structures. Once initial results are complete, more c...
20 citations