Changes in fatigue strength due to cyclic prestress: II. Fatigue tests of aluminium alloy specimens and evaluation by means of the sequential Wohler curve conceptPusche, A.C. IfL-Mitt. Mar.–Apr. 1989 28, (2), 43–49 (in German)

1990 ◽  
Vol 12 (4) ◽  
pp. 299-299
Keyword(s):  
Fatigue Strength ◽  
Aluminium Alloy ◽  
Fatigue Tests

scholarly journals Investigation on Influence of Ultrasonic Impact Treatment (UIT) on Fatigue Life for Aluminium Alloy 2017-T4

2018 ◽  
Vol 21 (1) ◽  
pp. 141 ◽  
Author(s):  
Hussain J. M. Alalkawi ◽  
Aseel A. Alhamdany ◽  
Marib R. Abdul Hassan
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Ambient Temperature ◽  
Aluminium Alloy ◽  
Mechanical Design ◽  
Fatigue Tests ◽  
Strong Tendency ◽  
Ultrasonic Impact Treatment ◽  
Variable Amplitude

Improving fatigue life is one of the most important issues in mechanical design; an investigation has been conducted on Al 2017-T4. Group of samples have been machined and prepared, some of specimens have been treated using the ultrasonic impact treatment (UIT) with one line peening. The fatigue tests were carried out under constant and variable amplitude (R=-1) at ambient temperature, in order to find out the fatigue life S-N curve and strength after treatment. It has been found significant increasing in strength after it was treated by (UIT).  The fatigue strength is improved after treatment up to 4.16% at 107 cycles, enhancement are present with 24% and 18.78% for the cumulative fatigue lives low-high and high–low respectively.  These results also show a strong tendency of increasing of fatigue strength after application of (UIT) with increase in mechanical properties of material used.

Design Analysis and Fatigue Testing of the Typical Structural Details of Aluminium Ships

2018 ◽  
Author(s):  
Huilong Ren ◽  
Kaikai Ma ◽  
Chenfeng Li ◽  
Zhichao Zhang ◽  
Weijun Xu ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Aluminium Alloy ◽  
Fatigue Testing ◽  
Hot Spot ◽  
Fatigue Tests ◽  
Material Strength ◽  
Original Design ◽  
Hot Spot Stress ◽  
Strength Assessment ◽  
Structural Details

Aluminium alloy is widely used structural design in light-weighting design. Due to the material strength loss in welding, fatigue strength of typical joints fabricated by aluminium alloy is more sensitive than steel joints. The aim of this study is to investigate one aluminium detail of the longitudinal through the transverse, with high-performance of fatigue strength compared to the original design. The alloy of longitudinal is AA6082-T6 and the other components (including plate and transverse) is AA5083-H2. Firstly, eight schemes of structural details with various configurations of bracket and / or stiffener are designed. Based on the finite element analyses, the stress distribution of panels with eight designed details is obtained under typical loading condition respectively. According to the principle of hot spot stress being minimum, the optimal detail is determined, which using stiffener reinforced on both sides of transverse. Secondly, the fatigue tests of the optimal detail were designed and carried out. The testing panels consist of 2-span and 3 longitudinal stiffeners, and the frame with optimal joints is located in the middle of the panels. The test panels were simply supported at two ends with applied cyclic loading in the middle panel. According to the designed loading scheme (loading level, frequency, etc.), the fatigue tests of the panels with typical detail were carried out. The hot stress and the cycle times of the typical detail under different load levels were obtained. Based on the test data, the S-N curve of the typical detail in aluminium alloy is established. Finally, the fatigue strength assessment of the typical detail in target ship is performed based on the Miner’s linear cumulative damage theory and established S-N curve. The results show that the fatigue life of proposed optimal detail meets the design requirements of the target ship. The S-N curve of the typical detail made of AA6082-T6 obtained in this study can be also used for other aluminium ships with similar structural details.

Thermal Ageing Effects on the Residual Fatigue Strength of AA2618-T6511 Aluminium Alloy

2006 ◽  
Vol 324-325 ◽  
pp. 1095-1098 ◽  
Author(s):  
Pier Gabriele Molari ◽  
Piero Morelli ◽  
Sergio Maldotti ◽  
Tito Poli
Keyword(s):  
Fatigue Strength ◽  
Aluminium Alloy ◽  
Thermal Ageing ◽  
Fatigue Tests ◽  
Design Tool ◽  
Artificial Ageing ◽  
Thermal Cycles ◽  
Practical Applications ◽  
Rotating Machine ◽  
Residual Fatigue

This work presents the results of an experimental investigation on the effects of thermal ageing over the residual fatigue strength of AA2618-T6511 aluminium alloy. Among others, this kind of light alloy finds practical applications in highly stressed engine components, such as pistons, that are typically subjected to both thermal and fatigue loads. Thermal cycles are responsible for ageing phenomena, that involve the precipitation of silicates, with a corresponding progressive damage of the microstructure and weakening of the mechanical characteristics of the material. Artificial ageing has been reproduced in laboratory by means of thermal cycles controlled in time and temperature. These variables have been correlated to the hardness values measured on the surface of specimens. Bending fatigue tests have been performed on a rotating machine in a temperature controlled environment. The experimental S-N diagram is finally presented, as a function of the tested temperature, in order to provide a design tool for the fatigue life estimation of AA2618 components.

Some Fatigue Tests on Aluminium-alloy and Mild-steel Sheet, with and without Drilled Holes

1951 ◽  
Vol 165 (1) ◽  
pp. 125-140 ◽  
Author(s):  
C. E. Phillips ◽  
A. J. Fenner
Keyword(s):  
Fatigue Strength ◽  
Mild Steel ◽  
Aluminium Alloy ◽  
Marked Reduction ◽  
Steel Sheet ◽  
Fatigue Tests ◽  
Slight Reduction ◽  
Maximum Width ◽  
Steel Panels ◽  
Comparison Of The Results

This paper describes fatigue tests, under pulsating direct stress, of aluminium-alloy and mild-steel panels, with and without central holes, approximately 0·1 inch in thickness and up to 12 inches in maximum width. Comparison of the results of tests on panels of similar shapes but of different sizes shows that larger panels are relatively weaker. The influence on the fatigue strength of varying the size of a drilled hole in a wide panel has been explored over a range of hole-diameters from to of the net width. While, in general, the presence of a hole causes a marked reduction in fatigue strength, the smallest holes result in only a slight reduction.

scholarly journals Effect of micro-notches on fatigue strength of electrodeposited nanocrystalline nickel thin films

2018 ◽  
Vol 165 ◽  
pp. 04011
Author(s):  
Keisuke Tanaka ◽  
Yuta Murase ◽  
Hirohisa Kimachi
Keyword(s):  
Thin Films ◽  
Fatigue Strength ◽  
Fatigue Limit ◽  
Stress Ratio ◽  
Fatigue Crack Initiation ◽  
Fatigue Tests ◽  
Fine Grained ◽  
Nickel Thin Films ◽  
Nano Crystalline ◽  
Fictitious Crack

The effect of micro-notches on the fatigue strength of nickel thin films was studied. Two types of thin films with 10 μm thickness were produced by electrodeposition using sulfamate solution without and with brightener: ultra-fine grained film (UFG) with the grain size of 384 nm and nano-crystalline grained film (NCG) with that of 17 nm. Micro-sized notches introduced by FIB had the width of 2 μm and various depths from 8 to 150μm. Fatigue tests were conducted under the stress ratio of 0.1. The fatigue strength decreased with increasing depth of notches. NCG had much higher strength than UFG compared at the same notch depth. Notches as small as 8μm did reduce the fatigue strength of both UFG and NCG. The fatigue limit was controlled by the initiation of cracks and no non-propagating crack was observed in specimens fatigued below the fatigue limit. A model of fictitious crack successfully predicted the reduction of the fatigue limit due to micro-notches. The characteristic crack length of NCG was much smaller than the UFG, while the fatigue strength of defect-free NCG was larger than that of UFG. SEM observation of fracture surfaces was conducted to reveal micromechanisms of fatigue crack initiation.

Influence of Inner Surface Defects on the Fatigue Strength of Pipe Subjected to Cyclic Internal Pressure

1978 ◽  
Vol 100 (4) ◽  
pp. 360-368
Author(s):  
Y. Yazaki ◽  
S. Hashirizaki ◽  
S. Nishida ◽  
C. Urashima
Keyword(s):  
Fatigue Strength ◽  
Internal Pressure ◽  
Test Specimen ◽  
Surface Defects ◽  
Fatigue Crack Initiation ◽  
Internal Surface ◽  
Fatigue Tests ◽  
Inner Surface ◽  
Surface Notch ◽  
Medium Diameter

Cyclic internal oil pressure fatigue tests were carried out on medium-diameter ERW pipes of API 5LX - X60 in an attempt to determine the influence of surface defects on the fatigue strength. Experimental factors investigated were the depth and location of internal surface notch in relation to the axis of pipe. The specimen was subjected to cyclic internal pressure, the cyclic rate being 0.3–0.5 Hz. During the test, Acoustic Emission (AE) techniques were applied to detect the fatigue crack initiation. Along with the aforementioned fatigue tests, pulsating tension fatigue tests were carried out on specimens with the same surface notches as the cyclic internal pressure fatigue test specimen.

The effect on the fatigue strength of bone cement of adding sodium fluoride

2001 ◽  
Vol 215 (2) ◽  
pp. 251-253 ◽  
Author(s):  
C Minari ◽  
M Baleanil ◽  
L Cristofolini ◽  
F Baruffaldi
Keyword(s):  
Fatigue Strength ◽  
Bone Cement ◽  
Sodium Fluoride ◽  
Biomedical Applications ◽  
Cement Mantle ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Bone Cements ◽  
The Novel ◽  
Pmma Bone Cement

New bone cements that include several additives are currently being investigated and tested. One such additive is sodium fluoride (NaF), which promotes bone formation, facilitating implant integration and success. The influence of NaF on the fatigue performance of the cement as used in biomedical applications was tested in this paper. In fact fatigue failure of the cement mantle is a major factor limiting the longevity of a cemented implant. An experimental bone cement with added NaF (12wt%) was investigated. The fatigue strength of the novel bone cement was evaluated in comparison with the cement without additives; fatigue tests were conducted according to current standards. The load levels were arranged based on a validated, statistically based optimization algorithm. The curve of stress against number of load cycles and the endurance limit were obtained and compared for both formulations. The results showed that the addition of NaF (12 wt %) to polymethylmethacrylate (PMMA) bone cement does not affect the fatigue resistance of the material. Sodium fluoride can safely be added to the bone cement without altering the fatigue performance of the PMMA bone cement.

Effect of Processing Layer on Fatigue Strength of Extruded AZ61 Magnesium Alloy

2013 ◽  
Vol 577-578 ◽  
pp. 429-432 ◽  
Author(s):  
Yukio Miyashita ◽  
Kyohei Kushihata ◽  
Toshifumi Kakiuchi ◽  
Mitsuhiro Kiyohara
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Magnesium Alloy ◽  
Crack Initiation ◽  
Crack Growth ◽  
Fatigue Crack Initiation ◽  
Fatigue Tests ◽  
Crack Growth Resistance ◽  
Az61 Magnesium Alloy

Fatigue Property of an Extruded AZ61 Magnesium Alloy with the Processing Layer Introduced by Machining was Investigated. Rotating Bending Fatigue Tests were Carried out with the Specimen with and without the Processing Layer. According to Results of the Fatigue Tests, Fatigue Life Significantly Increased by Introducing the Processing Layer to the Specimen Surface. Fatigue Crack Initiation and Propagation Behaviors were Observed by Replication Technique during the Fatigue Test. Fatigue Crack Initiation Life of the Specimen with the Processing Layer was Slightly Longer than that of the Specimen without the Processing Layer. Higher Fatigue Crack Growth Resistance was also Observed when the Fatigue Crack was Growing in the Processing Layer in the Specimen with the Processing Layer. the Longer Fatigue Life Observed in the Fatigue Test in the Specimen with the Processing Layer could be Mainly due to the Higher Crack Growth Resistance. it is Speculated that the Fatigue Strength can be Controlled by Change in Condition of Machining Process. it could be Effective way in Industry to Improved Fatigue Strength only by the Cutting Process without Additional Surface Treatment Process.

Fatigue of Autofrettaged Thick Tubes: Closed and Open Ended; As-Received and Honed

1983 ◽  
Vol 105 (3) ◽  
pp. 195-201 ◽  
Author(s):  
W. N. Findley ◽  
R. M. Reed
Keyword(s):  
Fatigue Strength ◽  
Fatigue Tests ◽  
Steel Tubes

Results of fatigue tests are presented for thick tubes of 32.3 mm (1.27 in) ID and wall ratio of 2.5 of SAE 4333 steel. Tubes having both as-received and honed bores were autofrettaged to three different degrees. Results are given for both open-ended and closed-ended autofrettage. Autofrettage increased the fatigue strength as much as 107 percent. Over autofrettage and open-ended autofrettage produced results not much different from closed-ended normal autofrettage. Under autofrettage causing half the change in diameter of normal autofrettage produced 21 percent less fatigue strength than normal autofrettage.

scholarly journals Influence Of Large Non-Metallic Inclusions On Bending Fatigue Strength Hardened And Tempered Steels

2015 ◽  
Vol 15 (3) ◽  
pp. 33-40
Author(s):  
T. Lipiński ◽  
A. Wach ◽  
E. Detyna
Keyword(s):  
Fatigue Strength ◽  
Structural Steel ◽  
Treatment Options ◽  
Fatigue Tests ◽  
Relative Volume ◽  
Heat Processing ◽  
Industrial Plant ◽  
Boron Steel ◽  
Metallic Inclusions ◽  
Steel Sections

Abstract The article discusses the effect of large oxide impurities (a diameter larger than 10 μm in size) on the fatigue resistance of structural steel of high purity during rotary bending. The study was performed on 7 heats produced in an industrial plant. The heats were produced in 140 ton electric furnaces. All heats were desulfurized. The experimental material consisted of semi-finished products of high-grade, carbon structural steel with: manganese, chromium, nickel, molybdenum and boron. Steel sections with a diameter of 18 mm were hardened from austenitizing by 30 minutes in temperature 880°C and tempered at a temperature of 200, 300, 400, 500 and 600°C for 120 minutes and air-cooled. The experimental variants were compared in view of the heat treatment options. Fatigue tests were performed with the use of a rotary bending machine at a frequency of 6000 cpm. The results were statistical processed and presented in graphic form. This paper discusses the results of the relative volume of large impurities, the fatigue strength for various heat processing options.

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