Vibration Fatigue Behavior of 2024-T62 Aluminum Alloy Cantilever Beam under Different Vibration State

The vibration fatigue experiments of cantilever beam structures were performed to investigate the fatigue behavior of 2024-T62 aluminum alloy. Two types of cantilever beams with various natural frequencies under the sinusoidal excitation were investigated. The initial stress of two types of specimens were set in the same amplitude by adjusting the acceleration of electrodynamic shaker. Based on the stress history recorded by the strain gauge in fatigue test and the Miners liner cumulative damage rule, the fatigue damage of the cantilever beam was calculated. The effect of vibration state on the vibration fatigue behavior of the cantilever beam was discussed. The experiment results show that the fatigue life of the cantilever beam, of which the initial vibration state is resonance, is longer than that of non-resonance. The calculated damage results were in accord with the reduction of the natural frequency measured in experiment. The reduction of natural frequency could be used to evaluate the fatigue damage of structures.

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Nonlinear Cumulative Fatigue Damage Model

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.328-330.1440 ◽

2011 ◽

Vol 328-330 ◽

pp. 1440-1444

Author(s):

Hua Zou ◽

Qiang Li ◽

Shou Guang Sun

Keyword(s):

Mathematical Model ◽

Aluminum Alloy ◽

Fatigue Life ◽

Fatigue Damage ◽

Welded Joint ◽

Damage Model ◽

Reasonable Explanation ◽

Curve Method ◽

Cumulative Fatigue Damage ◽

Damage Rule

Cumulative fatigue damage is an important consideration in determining the fatigue life of structures. A cumulative linear damage rule cannot provide a reasonable explanation for cumulative fatigue damage, but a damage curve method based on nonlinear cumulative fatigue damage model can give a reasonable explanation. In this paper, a specific mathematical model is put forward, which is based on the damage curve method. In the model, miner formula is modified properly and an exponent formula is give out to fit the damage accumulate. According to a two-step fatigue test of aluminum–alloy welded joint, the comparison between the calculated results and the testing results is less than 5%. It shows that the model is reasonable and accuracy.

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Corrosion mechanism and fatigue behavior of 2A70-T6 aluminum alloy under alternating corrosion and fatigue

Anti-Corrosion Methods and Materials ◽

10.1108/acmm-02-2020-2265 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Lei Fu ◽

Hui Li ◽

Li Lin ◽

Qingyuan Wang ◽

Qi Fan ◽

...

Keyword(s):

Aluminum Alloy ◽

Fatigue Life ◽

Corrosion Fatigue ◽

Intergranular Corrosion ◽

Fatigue Behavior ◽

Cumulative Damage ◽

Corrosion Mechanism ◽

Corrosive Environment ◽

Content Type ◽

Damage Rule

Purpose Most supersonic aircraft were manufactured using 2A70 aluminum alloy. The purpose of this paper is to study the corrosion mechanism and fatigue behavior of an aircraft in a semi-industrial atmospheric corrosive environment, alternating effects of corrosion and fatigue were used to simulate the aircraft’s ground parking corrosion and air flight fatigue. Design/methodology/approach For this purpose, the aluminum alloy samples were subjected to pre-corrosion and alternating corrosion-fatigue experiments. The failure mechanisms of corrosion and corrosion fatigue were analyzed using microscopic characterization methods of electrochemical testing, X-ray diffraction and scanning electron microscopy. Miner’s linear cumulative damage rule was used to predict the fatigue life of aluminum alloy and to obtain its safe fatigue life. Findings The results showed that the corrosion damage caused by the corrosive environment was gradually connected by pitting pits to form denudation pits along grain boundaries. The deep excavation of chloride ions and the presence of intergranular copper-rich phases result in severe intergranular corrosion morphology. During cyclic loading, alternating hardening and softening occurred. The stress concentration caused by surface pitting pits and denudation pits initiated fatigue cracks at intergranular corrosion products. At the same time, the initiation of multiple fatigue crack sources was caused by the corrosion environment and the morphology of the transient fracture zone was also changed, but the crack propagation rate was not basically affected. The polarization curve and impedance analysis results showed that the corrosion rate increases first, decreases and then increases. Fatigue failure behavior was directly related to micro characteristics such as corrosion pits and microcracks. Originality/value In this research, alternating effects of corrosion and fatigue were used to simulate the aircraft’s ground parking corrosion and air flight fatigue. To study the corrosion mechanism and fatigue behavior of an aircraft in a semi-industrial atmospheric corrosive environment, the Miner’s linear cumulative damage rule was used to predict the fatigue life of aluminum alloy and to obtain its safe fatigue life.

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Some Investigations on Effect of Notch on Dynamics Characteristics of Cantilever Beams

10.20855/ijav.2019.24.11121 ◽

2019 ◽

Vol 24 (No 1) ◽

pp. 20-27

Author(s):

S. H. Gawande ◽

R. R. More

Keyword(s):

Finite Element Method ◽

Natural Frequency ◽

Cantilever Beam ◽

Vibration Analysis ◽

Dynamic Properties ◽

Comprehensive Analysis ◽

Cantilever Beams ◽

Notch Depth ◽

Paper Work ◽

Set Up

Beams are very important as per engineering applications is concern and it undergoes different type of loading. Because of different type of loadings there may be chance of failure of structures due to generation of notch.Therefore notch depth and its location are the main parameters for the vibration analysis of beams.The notch depth and its position may affect the natural frequency. Hence, it is essential to study the effect of notch depth and its position on modal natural frequency of the beam for the good performance and its safety. This paper work focus on the examination of these changes, which are useful for identification of notch place.The material of the beam is seleced as mild steel. In this work the comprehensive analysis of cantilever beam with and without notch has been done using analytical analysis and finite element method (FEM) with the help of ANSYS and experimentally using modern National Instruments (NI) Lab-view technique. An experimental set up was developed in which a cantilever beam was excited by a hammer and the response was obtained using an accelerometer.This method describes the relation between the various dynamics characteristics as modal natural frequency and notch depth, modal natural frequency with notch location. This paper focus on the study of dynamic properties of cantilever beams subjected to free vibration under the influence of notch at different points along the length.

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Fundamental Frequencies of Cantilever Beams

Volume 7A: 17th Biennial Conference on Mechanical Vibration and Noise ◽

10.1115/detc99/vib-8136 ◽

1999 ◽

Author(s):

Jon A. Hoffmann ◽

Todd Wertheimer

Keyword(s):

Natural Frequency ◽

Cantilever Beam ◽

Mass Distribution ◽

Distribution Parameter ◽

Simple Relationship ◽

Cantilever Beams ◽

Mass Ratio ◽

Fundamental Frequencies ◽

Tapered Cantilever Beam

Abstract A simple relationship which predicts the first mode natural frequency of a tapered cantilever beam is presented as a function of the stiffness to mass ratio and a mass distribution parameter for the beam. In this study the mass distribution parameter, obtained using referenced results, is presented as a function of the taper ratio of the beam for the case of beams with linear tapers. Conical truncated beams, truncated wedges with vibration perpendicular to the parallel sides of the taper, and truncated wedges with vibration parallel to the parallel sides of the taper have been investigated.

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Vibrations of Tapered Cantilever Beams and Shafts

Aeronautical Quarterly ◽

10.1017/s0001925900004972 ◽

1969 ◽

Vol 20 (2) ◽

pp. 171-177 ◽

Cited By ~ 2

Author(s):

A. V. Krishna Murty ◽

K. R. Prabhakaran

Keyword(s):

Natural Frequency ◽

Cantilever Beam ◽

Mode Shape ◽

Linear Displacement ◽

Inertia Force ◽

Cantilever Beams ◽

Displacement Distribution ◽

Force Method ◽

Reasonable Degree ◽

Tapered Cantilever Beam

SummaryVibration characteristics of a linearly tapered cantilever beam and a shaft have been studied by using the lumped inertia force method; a linear displacement distribution is considered over each element. The results are compared with some of those in the literature and with experimental observations. These comparisons indicate that, even using a few elements, a reasonable degree of accuracy can be obtained in the natural frequency, although it is essential to consider more elements in order to determine mode shape accurately.

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Fatigue Test Research for SPR Aluminum Alloy Sheet

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.44-47.2557 ◽

2010 ◽

Vol 44-47 ◽

pp. 2557-2561 ◽

Cited By ~ 1

Author(s):

Jing Hua Zhao ◽

Shu Min Wan ◽

Shuang Yi Li ◽

Feng Liu

Keyword(s):

Aluminum Alloy ◽

Fatigue Test ◽

Spot Welding ◽

Fatigue Behavior ◽

Testing Machine ◽

Alloy Sheet ◽

Regression Analyses ◽

Factor Analyses ◽

Test Parameters ◽

Damage Rule

In this paper, the fatigue behavior of self-piercing riveting (SPR) joints is compared with resistance spot welding (RSW) joints for the same A6063 aluminum alloy sheets. The fatigue test, where every specimen is tested under different load, is conducted on MTS810.23M testing machine, and the results show that SPR joints have superior fatigue performances. Next S-N curve of every specimen is deduced after regression analyses of test data and the fatigue damage rule of SPR aluminum alloy sheets is summarized. Finally the effect of test parameters and errors on fatigue life of RSW and SPR joints is evaluated with two-factor and multiple factor analyses of variance.

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