scholarly journals Effects of chamfering, cold expansion, bolt clamping, and their combinations on fatigue life of aluminum–lithium alloy single plate

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401775068
Author(s):  
Yongjie Huang ◽  
Zhidong Guan ◽  
Haitao Li ◽  
Xu Yang ◽  
Zengshan Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Three Dimensional ◽  
Fatigue Tests ◽  
Cold Expansion ◽  
Lithium Alloy ◽  
Single Plate ◽  
Aluminum Lithium Alloy ◽  
Aluminum Lithium ◽  
Three Dimensional Finite Element

The objective of this study was to establish the effects of cold expansion, chamfering, bolt clamping, and their combinations on the fatigue life of an aluminum–lithium alloy single plate. Fatigue tests were conducted to quantify the anti-fatigue effects of the different techniques. A scanning electron microscope was used to perform fracture analyses of the used specimens, and the residual stresses were measured using an X-ray diffraction device. In addition, three-dimensional finite element models of the specimens were established and used to characterize their stress states, and the Smith–Watson–Topper method was used to predict the fatigue lives of the specimens. The fatigue test results showed that all the considered processes improved the fatigue life of the pristine specimen. The most effective was a combination of 3.2% cold expansion, 1-mm chamfering, and bolt clamping using a 6.4-N m torque, which improved the fatigue life of the pristine specimen by a factor of 15.5. The finite element method results also revealed that this combination decreased the maximum stress and confirmed its superiority in relation to the other fatigue-life enhancement techniques in terms of the anti-fatigue effect. The Smith–Watson–Topper method underestimated the specimen fatigue life, but the accuracy satisfied engineering requirements.

Progressive fatigue behavior of single-lap bolted laminates under different tightening torque magnitudes

2020 ◽  
Vol 234 (10) ◽  
pp. 1303-1312
Author(s):  
M Feyzi ◽  
S Hassanifard ◽  
A Varvani-Farahani
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Fatigue Behavior ◽  
Damage Model ◽  
Three Dimensional ◽  
Bolted Joints ◽  
Element Analysis ◽  
Damage And Failure ◽  
Experienced Fatigue ◽  
Three Dimensional Finite Element

The present paper studies fatigue damage and life of single-lap bolted joints tightened with different torque magnitudes subjected to uniaxial load cycles. The adherends were constructed from E-glass/epoxy layers using a hand layup technique and assembled by 1.5, 3, and 8 N m of applied torques. Increasing the torque magnitude benefitted the final fatigue life of the joints so that the high-cycle fatigue life of the joint sample tightened with 8 N m was as high as 10 times that of the joint tightened with 1.5 N m. In the numerical section of this study, a three-dimensional finite element analysis was employed, and the impacts of applied torques were included in the progressive damage model to assess damage and failure in the bolted joints. For the joints tightened with higher torque levels, numerical results revealed higher fatigue lives but at the cost of more delamination at the vicinity of the hole. Laminate fracture surface was investigated through scanning electron microscopy and more cracking/damage progress was evidenced in matrix, fiber, and matrix–fiber interface as composite joints experienced fatigue cycles. Experimental life data of tested joints agreed with those anticipated through the use of finite element analyses indicating the developed model as an appropriate tool in evaluating the effects of applied torques on the fatigue fracture behavior of bolted laminates.

Fatigue Life Evaluation of Vehicle Wheel Bolts under Random Loading

2005 ◽  
Vol 297-300 ◽  
pp. 1770-1775 ◽  
Author(s):  
Young Woo Choi ◽  
Byeong Wook Noh ◽  
Kyung Chun Ham ◽  
Sung In Bae
Keyword(s):  
Fatigue Life ◽  
Residual Life ◽  
Three Dimensional ◽  
Real Life ◽  
Local Stress ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Random Loading ◽  
Element Analysis ◽  
Three Dimensional Finite Element

The fatigue life of hexagon head and socket head bolts, attached to vehicle a wheel, is assessed and the estimation of the residual life of existing bolts in vehicle wheel is investigated. Field- measured load histories were applied in this test. Tensile tests and fatigue tests were performed to evaluate the effect of tightening torque and to obtain the basic experimental data. A three-dimensional finite element analysis was also performed to evaluate the local stress fields. Miner’s rule was used to predict the fatigue life of bolts. The results indicate the prediction of fatigue life of the bolts was in good agreement with the real life of vehicle wheel bolts in this test.

Three Dimensional Finite Element Analysis of a Split-Sleeve Cold Expansion Process

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
S. Ismonov ◽  
S. R. Daniewicz ◽  
J. C. Newman ◽  
M. R. Hill ◽  
M. R. Urban
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Residual Stress Field ◽  
Expansion Process ◽  
Element Analysis ◽  
Cold Expansion ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

A cold expansion process is used to prolong the fatigue life of a structure under cyclic loadings. The process produces a beneficial compressive residual stress zone in the hole vicinity, which retards the initiation and propagation of the crack at the hole edge. In this study, a three-dimensional finite element model of the split-sleeve cold expansion process was developed to predict the resulting residual stress field. A thin rectangular aluminum sheet with a centrally located hole was considered. A rigid mandrel and an elastic steel split sleeve were explicitly modeled with the appropriate contact elements at the interfaces between the mandrel, the sleeve, and the hole. Geometrical and material nonlinearities were included. The simulation results were compared with experimental measurements of the residual stress. The influence of friction and the prescribed boundary conditions for the sheet were studied. Differences between the split-sleeve- and the non-split-sleeve model solutions are discussed.

Effect of Friction on Residual Stress Distribution Induced by Split Sleeve Cold Expansion Process

2020 ◽  
Author(s):  
Mithun K. Dey ◽  
Dave Kim ◽  
Hua Tan
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Compressive Residual Stress ◽  
Three Dimensional ◽  
Element Model ◽  
Residual Stress Distribution ◽  
Expansion Process ◽  
Cold Expansion ◽  
Three Dimensional Finite Element

Abstract Residual Stress distribution and parametric influence of friction are studied for the split sleeve cold expanded holes in Al 2024 T351 alloy, by developing a three-dimensional finite element model of the process. Fastener holes in the alloy are necessary for the manufacturing process, but they create a potential area for stress concentration, which eventually leads to fatigue under cyclic loading. Beneficial compressive residual stress distribution as a result of the split sleeve cold expansion process provides retardation against crack initiation and propagation at the critical zones near hole edges. In this parametric study, the influence of friction between contact surfaces of the split sleeve and mandrel is numerically investigated. Hole reaming process after split sleeve cold expansion is often not discussed. Without this post-processing procedure, split sleeve cold expansion is incomplete in practice, and its purpose of providing better fatigue performance is invalidated. This study presents results and an overview of the significance of friction with the consideration of the postprocessing of split sleeve cold expansion. The numerical results show that with increasing friction coefficient, compressive residual stress reduces significantly at the mandrel entry side, which makes the hole edge more vulnerable to fatigue. The different aspects of finite element modeling approaches are also discussed to present the accuracy of the prediction. Experimental residual stress observation or visual validation is expensive and time-consuming. So better numerical prediction with the transparency of the analysis design can provide critical information on the process.

Mechanics Research with Prediction on the Fatigue Life of the Five-Cylinder Emulsion Pump Crankshaft

2013 ◽  
Vol 738 ◽  
pp. 163-166 ◽  
Author(s):  
Li Ran
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Working Conditions ◽  
Maximum Stress ◽  
Fatigue Crack Initiation ◽  
Three Dimensional ◽  
Finite Element Analyses ◽  
Mechanics Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In this paper, dynamic mechanics analysis was performed, in order to investigate the maximum forces acting on the crankshaft under working conditions. Then, three dimensional, finite element analyses have been conducted, in an attempt to predict the fatigue crack-initiation locations and lives. The maximum loadings, used in finite element analyses, were analytical obtained, which correspond to the five critical rotational angles of the first crankpin, i.e. = 40 º, 110º, 185 º, 255 º, 325 º. The maximum stress site was found to be approximately on the fillet of the first main journal of the crankshaft. The predicted fatigue life of the crankshafts was obtained by use of a stress-life (S-N) approach.

Effect of different temperatures on the fatigue behavior of interference fitted plates of Al-alloy 7075-T6

2017 ◽  
Vol 233 (7) ◽  
pp. 1324-1335
Author(s):  
H Taghizadeh ◽  
TN Chakherlou
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Thermal Cycle ◽  
Fatigue Behavior ◽  
Three Dimensional ◽  
Fatigue Tests ◽  
Al Alloy ◽  
Interference Fit ◽  
Short Period ◽  
Different Temperatures

The effect of short time exposure to thermal cycle on the fatigue life of interference fitted fastener holes was evaluated by experimental and numerical method in Al-alloy 7075-T6. When interference fitted holes are subjected to temperature, the pre-stresses produced by interference fit may be considerably redistributed. To investigate the pre-stresses redistribution and its effect on the fatigue life of interference fitted specimens, two different temperatures (i.e. 60 ℃ and 120 ℃), apart from room temperature, were selected. The fatigue tests were performed to obtain S–N curves. Tangential pre-stress distribution was analyzed by the finite element method. Three-dimensional stress distributions of interference fit process have been determined around the hole at three temperatures: 25 ℃, 60 ℃, and 120 ℃. The finite element analyses justify the experimentally observed fatigue test behavior. The results show that the short period thermal cycle could improve the fatigue life of the prepared samples.

Fatigue Behavior and Deformation of Aluminum and Steel HVOF Sprayed with WC-Co Coatings

1997 ◽  
Author(s):  
A. Ibrahim ◽  
C.C. Berndt
Keyword(s):  
Fatigue Life ◽  
Room Temperature ◽  
Fatigue Behavior ◽  
Three Dimensional ◽  
Element Model ◽  
Fatigue Tests ◽  
Dimensional Finite Element ◽  
Life Distributions ◽  
Three Dimensional Finite Element ◽  
Good Agreement

Abstract The effect of WC-Co coating on the high cycle fatigue (HCF) behavior of SAE 12L14 steel and 2024-T4 aluminum was investigated. The fatigue tests were performed at room temperature and 370°C. The fatigue life distributions of specimens in the polished, grit blasted, peened, and coated conditions are presented as a function of the probability of failure. HVOF sprayed WC-Co coating has influenced the fatigue life of aluminum and steel. Factors contributing to this influence, which include grit blasting, elastic modulus, and residual stress, are discussed. A three-dimensional finite-element model (FEM) of the coated specimen was used to calculate the stress distribution across the coating and the substrate. The results of the analytical model are in good agreement with fatigue lives observed experimentally.

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