Finite Fatigue Life Distributions of SAE 1008 Subjected to Various Load-Time Histories

1980 ◽  
Vol 102 (1) ◽  
pp. 135-140 ◽  
Author(s):  
H. A. ElMaraghy ◽  
J. N. Siddall
Keyword(s):  
Fatigue Life ◽  
Fatigue Testing ◽  
Narrow Band ◽  
Fatigue Properties ◽  
Load History ◽  
Random Load ◽  
Bending Fatigue ◽  
Theoretical Predictions ◽  
Time Histories ◽  
Life Distributions

The probabilistic fatigue properties of SAE 1008 steel were determined experimentally. A flexural bending fatigue testing program was carried out consisting of: (a) constant strain amplitude, (b) blocks of Hi-Lo and Lo-Hi-Lo strain amplitudes, and (c) narrow band random load history. Fatigue life of 30-45 specimens in each program were recorded and used to construct distributions of fatigue life. A computer simulation technique was used to predict these distributions. Experimental results and theoretical predictions are both presented for comparison.

Study on the Bending Fatigue Properties of Nomex Fiber

2014 ◽  
Vol 1048 ◽  
pp. 62-65
Author(s):  
Guang Ming Cai ◽  
Xin Wang
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Testing ◽  
Ccd Camera ◽  
Fracture Morphology ◽  
Fatigue Properties ◽  
Bending Angle ◽  
Bending Fatigue ◽  
Different Temperatures ◽  
Bending Fatigue Strength

In this paper, we reported a bending fatigue testing apparatus which can test the bending fatigue properties of single Nomex fiber by setting the pretension, bending angle and temperature. The S-N and θ-N curves indicated that the pre-tension and bending angle had great influences on the bending fatigue life of Nomex fiber. A CCD camera was utilized to allow observation of the bending fatigue fracture morphology of fiber. It showed the fracture mechanism of Nomex fibers. The bending fatigue life of Nomex fiber was tested at different temperatures to show that its bending fatigue strength is strongly influenced by the temperature.

Bending fatigue testing of gear teeth under random loading

2001 ◽  
Vol 215 (7) ◽  
pp. 773-784 ◽  
Author(s):  
D Hanumanna ◽  
S Narayanan ◽  
S Krishnamurthy
Keyword(s):  
Fatigue Life ◽  
Power Transmission ◽  
Fatigue Testing ◽  
Cumulative Damage ◽  
Loading Conditions ◽  
Test Rig ◽  
Random Loading ◽  
Random Load ◽  
Bending Fatigue ◽  
Modes Of Failure

The gears in a gear box fitted in an armoured tracked vehicle for the purpose of power transmission and positioning of rotating heavy mass to the desired angle with high accuracy are subjected to fluctuating loads that are random in nature. One of the important modes of failure in cyclic loading conditions including random loads is fatigue failure. It is thus important from the design point of view to estimate the life of the gears under these conditions. The fatigue life of components subjected to sinusoidal loading can be estimated by using cumulative damage theories. Their extension to random load fatigue, though straightforward, may not be very accurate owing to inherent scatter exhibited by the fatigue phenomenon. It is therefore necessary experimentally to determine the fatigue life of randomly loaded components and establish the validity of the theoretical model. An electrohydraulic test rig has been designed and fabricated that is capable of generating different types of load pattern by adopting a suitable electronic circuit in the test rig. This paper presents the details of the test rig for random load generation, the test fixture for mounting the gear and the technique for testing the gear for bending fatigue life under random loading. A gear has been tested in the test rig under random loading conditions and also under constant amplitude conditions for bending fatigue, and the life of the gear has been obtained experimentally. Fatigue lives of the gear have also been estimated theoretically by employing linear cumulative damage theory using the peak count method.

Fatigue of Metal Free Reed due to Self-Excited Oscillation

2008 ◽  
Vol 33-37 ◽  
pp. 267-272
Author(s):  
Yoshinobu Shimamura ◽  
Keiichiro Tohgo ◽  
Hiroyasu Araki ◽  
Yosuke Mizuno ◽  
Shoji Kawaguchi ◽  
...  
Keyword(s):  
Fatigue Testing ◽  
The Self ◽  
Fatigue Properties ◽  
Bending Fatigue ◽  
Metal Free ◽  
Mass Damper ◽  
Excited Oscillation ◽  
Analytical Research ◽  
Fatigue Characteristics ◽  
Good Agreement

Metal free reeds are used for musical instruments like harmonica. Free reeds are small, thin cantilevers, and oscillate by blowing air. It is reported that free reeds break due to fatigue during play. In order to elongate the life of free reeds, the fatigue properties should be investigated and a motion analysis method should be developed. The experimental and analytical research on metal free reed, however, has been rarely reported. In this study, two types of fatigue testing machines were developed to obtain basic fatigue characteristics. The fatigue testing machines are designed for bending fatigue of actual free reeds whose thickness is less than 400 μm. An S-N diagram is successfully obtained up to 107 cycles by using the developed fatigue testing machines. The fracture surfaces of fatigued specimens are in good agreement with those of free reeds failed in use. Then, an analytical method for the self-excited oscillation of free reeds was developed based on a mass-damper-spring model. The proposed method can take account for the shape of free reed. The self-excited oscillation of free reeds with different shape are analyzed and in good agreement with experimental results.

Improvement of Fatigue Behaviour of High Strength Aluminium Alloys by Fluidized Bed Peening (FBP)

2007 ◽  
Vol 344 ◽  
pp. 87-96 ◽  
Author(s):  
M. Barletta ◽  
F. Lambiase ◽  
Vincenzo Tagliaferri
Keyword(s):  
Fatigue Life ◽  
Fluidized Bed ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Maximum Amplitude ◽  
High Strength ◽  
Operational Parameters ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

This paper deals with a definition of a relatively novel technique to improve the fatigue behavior of high strength aluminum alloys, namely, Fluidized Bed Peening (FBP). Fatigue samples made from AA 6082 T6 alloy were chosen according to ASTM regulation about rotating bending fatigue test and, subsequently, treated by varying FBP operational parameters and fatigue testing conditions. First, a full factorial experimental plan was performed to assess the trend of number of cycles to rupture of fatigue samples varying among several experimental levels the factors peening time and maximum amplitude of alternating stress applied to fatigue samples during rotating bending fatigue tests. Second, design of experiment (DOE) technique was used to analyze the influence of FBP operational parameters on fatigue life of AA 6082 T6 alloy. Finally, ruptures of FB treated samples and untreated samples were discussed in order to evaluate the influence of operational parameters on the effectiveness of FBP process and to understand the leading process mechanisms. At any rate, the fatigue behavior of processed components was found to be significantly improved, thereby proving the suitability of FBP process as alternative mechanical technique to enhance fatigue life of components made from high strength aluminum alloy.

scholarly journals Study on Fatigue Test and Life Prediction of Polyurethane Cement Composite (PUC) under High or Low Temperature Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Hongshuai Gao ◽  
Quansheng Sun
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Asphalt Mixture ◽  
Cement Composite ◽  
Control Mode ◽  
Fatigue Properties ◽  
Coupling Condition ◽  
Bending Fatigue ◽  
Bending Fatigue Test ◽  
Steel Deck

There are many diseases in the deck pavement of long-span steel bridges under the action of vehicles, rainwater, and freezing. It is necessary to study a new type of pavement material with high waterproof property, light weight, and high bonding performance for steel deck pavement. Polyurethane cement composite (PUC) can be used for steel deck pavement. In order to find out the temperature effect on fatigue properties of PUC, the four-point bending fatigue test was carried out at different temperatures. In this paper, the optimum mix ratio of PUC was selected by compressive and flexural tests, and then the bending fatigue test was conducted under strain control mode. Under temperature and external force coupling condition, a method for predicting fatigue life of PUC is proposed by the combination of theoretical deduction and experimental research. The results show that the proposed formula can effectively describe the fatigue life and fatigue limit of PUC. Finally, compared with three different asphalt mixtures for steel deck pavement, it is found that the fatigue performance of polyurethane cement is better than that of asphalt mixture.

Study on Fatigue Properties of Double-Wall-Brazed-Tube

2011 ◽  
Vol 105-107 ◽  
pp. 1644-1647
Author(s):  
Qi Rong Zhu ◽  
Ming Ru Xie ◽  
Xiao Hua Li
Keyword(s):  
Experimental Data ◽  
Fatigue Life ◽  
Fatigue Testing ◽  
Shaking Table ◽  
Fatigue Properties ◽  
Metal Fatigue ◽  
Cross Sectional ◽  
Data Analysis Procedure ◽  
Cross Sectional Size ◽  
Double Wall

This paper is referred to other literature on properties of metal fatigue testing methods and data analysis procedure methods. According to high cycle fatigue testing, double-wall-brazed-tube is loaded with different stimulated vibration force by shaking table and is forced to vibrate. In the experience, strain of key parts is measured with Electrical resistance Strain measurement Methods. By curve fitting of experimental data, we gain the fitting function of the specimen’s fatigue life and draw its S-N curve. In accordance with the analysis of experimental data and S-N curves, it is concluded that fatigue properties of metallic materials can not fully reflect fatigue properties of a specimen and that the cross-sectional size of a specimen has much effects on its fatigue life.

Mechanical Properties of Cast Shape Memory Alloy for Brain Spatula

2011 ◽  
Vol 674 ◽  
pp. 213-218 ◽  
Author(s):  
Hisaaki Tobushi ◽  
K. Kitamura ◽  
Yukiharu Yoshimi ◽  
K. Miyamoto ◽  
K. Mitsui
Keyword(s):  
Fatigue Life ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Power Function ◽  
Tensile Deformation ◽  
Low Cycle Fatigue ◽  
Fatigue Properties ◽  
Bending Fatigue ◽  
Deformation Properties ◽  
Plane Bending

In order to develop a brain spatula or a brain retractor made of a shape memory alloy (SMA), the bending characteristics of the brain spatula of TiNi SMA made by the precision casting were discussed based on the tensile deformation properties of the existing copper and the TiNi rolled-SMA. The fatigue properties of both materials were also investigated by the plane-bending fatigue test. The results obtained can be summarized as follows. (1) The modulus of elasticity and the yield stress for the cast and rolled SMAs are lower than those for the copper. Therefore, the conventional rolled-SMA spatula and the new cast-SMA spatula can be bent easily compared to the existing copper-brain spatula. (2) With respect to the alternating- and pulsating-plane bending fatigue, the fatigue life of both the copper and the SMAs in the region of low-cycle fatigue is expressed by a power function of the maximum bending strain. The fatigue life of the conventional rolled SMA and the new cast SMA is longer than that of the existing copper. The fatigue life of the new cast and rolled SMAs in the pulsating-plane bending is longer than that in the alternating-plane bending. (3) The fatigue life of the rolled-SMA and the cast SMA for alternating- and pulsating-plane bendings can be expressed by the unified relationship with a power function of the dissipated work.

The Effect of Morphology and Distribution of Sulfides on Mechanical Properties and Fatigue Life of Non-Quenched and Tempered Steel

2008 ◽  
Vol 51 ◽  
pp. 11-20
Author(s):  
Ming Tu Ma ◽  
Guo Zhong Li ◽  
Zhi Gang Li ◽  
Hong Zhou Lu
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Fracture ◽  
Rolling Direction ◽  
Impact Fracture ◽  
Fatigue Properties ◽  
Bending Fatigue ◽  
Quenched And Tempered Steel ◽  
The Impact ◽  
Tempered Steel

The effect of morphology and distribution of sulfides on tensile, impact and bending fatigue properties of non-quenched and tempered steel 49MnVS3 has been investigated in this paper. Microscopic structure and morphology of sulfides are observed, and impact fracture and fatigue fracture have been analyzed by SEM. The results show that the morphology of sulfides is mostly strip and distributes in ferrite, which affects mechanical properties and fatigue life. The length direction of sulfide strip is parallel to the rolling direction of steel. When the length of sulfide is short relatively and is approximate to the shape of particles. The impact properties and bending fatigue performance of 49MnVS3 are higher. Under those conditions, there are more ductile characteristics in their impact fracture and the fatigue fracture. The reasons for the effect of sulfide morphology on the mechanical and fatigue properties are explained.

Fatigue Properties of a Ck45 Steel Coated with a Post-Heat Treated Ni-Cu-P Electroless Deposit

2006 ◽  
Vol 514-516 ◽  
pp. 574-578
Author(s):  
Sasan Yazdani ◽  
N. Parvini-Ahmadi ◽  
Tohid Saeid
Keyword(s):  
Fatigue Life ◽  
Fatigue Testing ◽  
Crack Nucleation ◽  
Fatigue Cracks ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Interfacial Cracks ◽  
Heat Treated ◽  
Base Steel ◽  
Surface Notch

The Fatigue tests under rotating bending conditions have been conducted on samples of a quenched and tempered Ck45 steel in two different conditions: (a) uncoated, (b) coated with an electroless Ni-Cu-P deposit, followed by a post-heat treatment (PHT) at 673 K for 1 h. Such a deposit had a thickness of approximately 10µm, with Cu and P contents of 6wt.% and 13.7wt.% respectively. The results indicate that plating the base steel with this kind of deposit leads to a reduction of the fatigue life of the material. The reduction in fatigue life has been quantified in terms of the Basquin parameters of the materials tested under different conditions. The microscopic observation of the fracture surfaces of the samples indicates that the reduction in fatigue life is associated with the nucleation of fatigue cracks on the coating-substrate interface and the deposit remains well adhered to substrate during fatigue testing since interfacial cracks have been very rarely observed. It is therefore concluded that, in the present case, the interface acts as a surface crack source or surface notch, which decreases the fatigue life of the coated material by reducing the crack nucleation stage.

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