Fatigue Strength of Shaft with Diameter Enlarged Partially by Cyclic Bending and Axial Compressive Loading

2012 ◽  
Vol 217-219 ◽  
pp. 2346-2350 ◽  
Author(s):  
Xia Zhu ◽  
Nagatoshi Okabe ◽  
Keiji Ogi ◽  
Manabu Takahashi
Keyword(s):  
Finite Element ◽  
Fatigue Strength ◽  
Notch Root ◽  
Compressive Loading ◽  
Mechanical Damage ◽  
Fatigue Tests ◽  
Stress And Strain ◽  
Plastic Working ◽  
Bending Fatigue ◽  
Hardness Values

This paper experimentally and analytically investigates the fatigue strength and of mechanical damage of the processed shafts. First, we carry out rotary bending fatigue tests and investigate the fatigue strength for smooth specimens, specimen made only using cutting work, and specimens processed using a new plastic working developed originally. Secondly, we measure the Vickers hardness values to investigate strain hardening near the processed part. Finally, we simulate stress and strain distributions of the shaft during the processing using finite element method (FEM) and calculate the stress concentration rate at the notch root of the processed part. Based on the processing experiments and the finite element analyses (FEA), we clarify that the plastic work mechanically does not reduce the fatigue strength of shafts in the processing range.

Influence of backing materials towards the fatigue strength of butt-welded joints

2011 ◽  
Vol 225 (8) ◽  
pp. 1798-1807 ◽  
Author(s):  
M H Kim ◽  
H J Kim ◽  
J H Han ◽  
J M Lee ◽  
Y D Kim ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Strength ◽  
Welded Joints ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Finite Element Analyses ◽  
Cold Metal Transfer ◽  
Notch Stress ◽  
Effective Notch Stress ◽  
Cold Metal

The purpose of this study is to investigate the fatigue strength of butt-welded joints with special attention paid to employing different kinds of backing plates. The effect of the under-matched weld was also considered. Four different cases of backing scenarios for butt-welded specimens such as steel backing, ceramic backing, CMT (no backing by cold metal transfer) and UM (under-matched welded specimen) were investigated. A series of fatigue tests was performed to compare the fatigue strength of butt-welded joints with respect to different backing scenarios. Effective notch stress was used for the interpretation of fatigue strength of butt-welded specimens with backing plates based on finite element analyses for calculating fatigue notch factors. When results were presented from the effective notch stress, all backing scenarios considered in this study exhibited the fatigue strengths corresponding to the FAT 225 curve. From the experimental results of this study, it was determined that the fatigue strengths of butt-welded joints were found to be in the order of CMT, ceramic backing, UM, and steel backing. No significant decrease in fatigue strength, however, was observed when backing plates were steel backing and ceramic backing types.

Fatigue Strength of Thick-Walled Cylinders Containing Cross Bores with Blending Features

1992 ◽  
Vol 206 (5) ◽  
pp. 299-309 ◽  
Author(s):  
L M Masu ◽  
G Craggs
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Tests ◽  
Cylinder Wall ◽  
Cylinder Bore

This paper reports on an investigation into the fatigue strength of thick-walled cylinders that contain a small transverse hole or cross bore in the cylinder wall having either a chamfer or a blending radius at its intersection with the main cylinder bore. Fatigue tests surprisingly show that plain cross-bore cylinders having thickness ratios K = 1.4 and 2.0 have a fatigue life that is marginally greater than comparable cylinders with blending features. A finite element investigation shows that local high stresses are produced on the surface of blending features and these stresses are considerably greater in magnitude than those found in plain cross-bore cylinders. These stress findings are used to explain the experimental fatigue life results obtained.

Effects of Overload on Fatigue Strength of SUS316 Having a Crack-Like Surface Defect

2010 ◽  
Author(s):  
Hiroko Oosedo ◽  
Koji Takahashi ◽  
Kotoji Ando
Keyword(s):  
Fatigue Strength ◽  
Fatigue Test ◽  
Surface Defect ◽  
Compact Tension ◽  
Crack Size ◽  
Fatigue Tests ◽  
Stress Intensity Factor Range ◽  
Bending Fatigue ◽  
Bending Fatigue Test ◽  
Key Factor

The effects of overload on the fatigue strength and threshold stress intensity factor range (ΔKth) in SUS316 were studied. Tensile overload was applied to compact tension (CT) specimens with a large crack and fatigue tests were carried out to determine the ΔKth. Tensile or compressive overload was applied to bending fatigue test specimens with a small crack-like surface defect and fatigue tests were carried out to determine the fatigue limit and ΔKth. It was found that the ΔKth increased by tensile overloading. The increasing rate of ΔKth in the CT specimen is larger than that in the bending fatigue test specimen. Thus, the crack size effects on the improvement of ΔKth after overloading were observed. The results are discussed from the viewpoint of fracture mechanics. The size of compressive residual stress is the key factor of the increasing rate.

Influence of Strength Level of Steels on Fatigue Strength and Fracture Morphology of Spot Welded Joints

2011 ◽  
Vol 462-463 ◽  
pp. 94-99
Author(s):  
Keiichiro Tohgo ◽  
Tomoya Ohguma ◽  
Yoshinobu Shimamura ◽  
Yoshifumi Ojima
Keyword(s):  
Finite Element ◽  
Fatigue Strength ◽  
Mild Steel ◽  
Welded Joints ◽  
High Strength ◽  
Fracture Morphology ◽  
Fatigue Tests ◽  
Finite Element Analyses ◽  
Ultra High Strength Steel ◽  
Spot Welded

In this paper, fatigue tests and finite element analyses are carried out on spot welded joints of mild steel (270MPa class) and ultra-high strength steel (980MPa class) in order to investigate the influence of strength level of base steels on fatigue strength and fracture morphology of spot welded joints. From the fatigue tests the following results are obtained: (1) Fatigue limit of spot welded joints is almost the same in both steels. (2) Fatigue fracture morphology of spot welded joints depends on the load level in the ultra-high strength steel, but not in the mild steel. From discussion based on the finite element analyses the following results are obtained: (3) The fatigue limit of spot welded joints can be predicted by stress intensity factors for a nugget edge, fracture criterion for a mixed mode crack and threshold value for fatigue crack growth in base steel. (4) Plastic deformation around a nugget in spot welded joints strongly affects the fatigue fracture morphology.

scholarly journals Experiment and Finite Analysis on Resonant Bending Fatigue of Marine Risers

2015 ◽  
Vol 9 (1) ◽  
pp. 205-212 ◽  
Author(s):  
Fang Xiaoming ◽  
Yan Zhichao ◽  
Wang Liquan ◽  
Huang Yuxuan
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Fatigue Test ◽  
Element Model ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Oil And Gas Development ◽  
Bending Fatigue ◽  
Bending Fatigue Test ◽  
The Finite Element Model

Riser system is a key equipment for offshore oil and gas development. When conducting riser design, fatigue failure mode is the chief one among the many failure modes which should be taken into account. To assess the fatigue performance of riser accurately, it is necessary to conduct fatigue tests. Resonant bending fatigue test is one effective method for fatigue tests of risers. In this paper, the principle of resonant bending fatigue test and test procedures are presented firstly, and then a finite element model using ABAQUS is created to simulate the resonant bending fatigue test, and the results from the finite element model are compared with the experimental results. The good agreements between the FEM results and experimental results verify the accuracy of the finite element model in this paper.

Stiffness and Fatigue Study for Surface Mounted Module/Lead/Card Systems

1991 ◽  
Vol 113 (2) ◽  
pp. 129-137 ◽  
Author(s):  
P. A. Engel ◽  
D. V. Caletka ◽  
M. R. Palmer
Keyword(s):  
Finite Element ◽  
Fatigue Strength ◽  
Analytical Modeling ◽  
Analytical Procedure ◽  
Fatigue Tests ◽  
Test Results ◽  
Element Computation ◽  
Card Test ◽  
Elastoplastic Range ◽  
Finite Element Computation

Modules attached to circuit cards by peripheral J- and gullwing leads were studied for their behavior under flexure. Three aspects of mechanical behavior were focused upon: the stiffness of the system, the forces arising in the leads, and the fatigue strength of the latter. The effective stiffness of a module-reinforced circuit card was measured experimentally in several configurations (load on card and load-on-module, double-sided and stacked). The leaded attachments were in two parallel rows. Analytical modeling of these tests were performed considering the leads as a continuous elastic foundation connecting the module and the card; test results were corroborated. Experiments were also conducted to establish the elastic and elastoplastic range of lead stiffness in three perpendicular directions: in two shearing planes and axially. The latter was the stiffest and most significant direction, motivating much of the present analysis. For lead force, the analytical procedure yielded values which were confirmed by finite element computation methods described previously by Engel (1990). Fatigue tests were performed on both J- and gullwing leads. Solder joints failed in the former, while lead failures occurred in the latter.

Fatigue Properties of Nitride Cr-Mo Steel with CrN Thin Film Deposited by Aip Method

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1554-1559 ◽  
Author(s):  
Daisuke Yonekura ◽  
Atsushi Tsukuda ◽  
Ri Ichi Murakami ◽  
Koji Hanaguri
Keyword(s):  
Thin Film ◽  
Residual Stress ◽  
Fatigue Strength ◽  
Film Thickness ◽  
Compressive Residual Stress ◽  
Optical Microscope ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Bending Fatigue ◽  
Three Point Bending

In this study, we selected the nitride Cr-Mo Steel SCM435 as the substrate. Attention was focussed on the effect of film thickness. The Arc Ion Plating was performed using Cr cathode and N2 gas. The specimens were prepared for the film thickness 6, 12 and 18μm The three point bending fatigue tests were performed at room temperature in a laboratory environment. After the fatigue test, crack initiation sites were examined by using an optical microscope and a scanning electron microscope. The results obtained were as follows: (1) A high compressive residual stress generated in the film, and the compressive residual stress of 12μm film thickness was the greatest. (2) The fatigue strength of coated specimens for thin film was slightly lower than for substrate. (3) The film thickness hardly affected the fatigue strength of coated specimens.

Research of Fatigue Limit and Stress Concentration on Structural Steel with Double-Notches

2009 ◽  
Vol 419-420 ◽  
pp. 849-852
Author(s):  
Sheng Wu Wang ◽  
Shu Juan Sun ◽  
Ai Ling Wen ◽  
Wei Da Wang ◽  
Shinichi Nishida
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fatigue Strength ◽  
Stress Concentration ◽  
Fatigue Limit ◽  
Three Dimensional ◽  
Fatigue Tests ◽  
Notched Specimen ◽  
Blind Hole ◽  
Element Method

The fatigue limit of parts and components that have the multi-notches is important data for the design and manufacture of machinery and traffic equipment which are operated under the high speed or pressure. In this paper the rotating bending fatigue tests have been carried out to investigate the fatigue limit of specimen with double-notch that is constructed of step and blind hole, and analyzed the effect of stress concentrations at the double-notched bottoms on the fatigue limits, using three-dimensional elastic finite element method. Firstly, the fatigue tests of 8 group specimens have been performed for examining the of fatigue limits of the single-notched specimen and double-notched specimen, respectively. Additionally, the stress field interactions between two stress fields by the blind hole notch and step are discussed using three-dimensional elastic finite element method. The main results obtained in this study are as follows: The fatigue limit of the double-notched specimen are down comparison with the fatigue limit of the single-notched specimen; the fatigue limit of the double-notch specimen is insensitive to distance between the blind hole and step for the low carbon structure steel with better ductility; for the high-strength steel, superposition and intensification of the stress concentration by the blind hole and step mutually may be avoided so that their adverse effects on the fatigue strength may be become to minimize, as take appropriate distance between the blind hole and step. The results are significant for the design of engineering design of the multi-notched parts, and the study of fatigue strength.

Effect of Radical Nitriding on Fatigue Strength of Ni-Base Superalloy

2009 ◽  
Vol 417-418 ◽  
pp. 205-208 ◽  
Author(s):  
Kazuhiro Morino ◽  
Norio Kawagoishi ◽  
K. Yamane ◽  
K. Fukada
Keyword(s):  
Fatigue Strength ◽  
Base Alloy ◽  
Compound Layer ◽  
Fatigue Tests ◽  
Bending Fatigue ◽  
Propagation Behavior ◽  
Initiation And Propagation ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Base Superalloy

In order to investigate the effect of nitriding on the crack initiation and propagation behavior of Ni-base super alloy, Alloy 718, rotating bending fatigue tests were carried out until 108 cycles at room temperature. By nitriding at 500°C for 12h, compound layer of about 5μm in thickness was formed and the initiation of a fatigue crack was strongly suppressed causing the increase in fatigue strength. A crack initiated in brittle manner at the compound layer in all of fractures. However the crack propagated in ductile manner controlled by the property of the base alloy. That is, there is no or little influence of nitriding on the crack growth rate of the alloy.

Effects of Heating Conditions on Residual Stresses, Hardened Layers and Bending Fatigue Strength of Induction Hardened Gears

2003 ◽  
Author(s):  
Kouitsu Miyachika ◽  
Hidefumi Mada ◽  
Satoshi Oda ◽  
Hiroshige Fujio ◽  
Hajime Tsuboi
Keyword(s):  
Fatigue Strength ◽  
Residual Stresses ◽  
Induction Hardening ◽  
Fatigue Tests ◽  
Heating Condition ◽  
Bending Fatigue ◽  
Optimum Heating ◽  
Bending Fatigue Strength

This paper presents a study on effects of heating conditions on residual stresses, hardened layers and bending fatigue strengths of induction hardened gears. Residual stresses and hardened layers of gears induction hardened under various heating conditions were calculated by means of the induction-hardening simulator, which had been developed by authors. Measurements of hardened layers and bending fatigue tests of gears induction hardened under various heating conditions were carried out. Calculated hardened layers were compared with measured ones. The optimum heating condition for the bending fatigue strength of induction-hardened gears was examined.

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