Fatigue Life Prediction for Overlap Friction Stir Linear Welds of Magnesium Alloys

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Ruijie Wang ◽  
Hong-Tae Kang ◽  
Chonghua (Cindy) Jiang
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Magnesium Alloys ◽  
Life Prediction ◽  
Low Cycle Fatigue ◽  
Fatigue Life Prediction ◽  
Structural Stress ◽  
Stress Strain ◽  
Friction Stir ◽  
Damage Equation

This work was undertaken to analyze the stress/strain state at the critical sites in friction stir welded specimens and, further, to assess the fatigue strength of friction stir welded specimens with conventional fatigue life prediction approaches. Elastoplastic and elastic finite-element stress/strain analyses were carried out for friction-stir-linear-welded (FSLW) specimens made of magnesium alloys. The calculated stress/strain at the periphery of the weld nugget was used to evaluate the fatigue life with local life prediction approaches. First, elastoplastic finite-element models were built according to experimental specimen profiles. Fatigue life prediction was conducted with Morrow's modified Manson–Coffin (MC) damage equation and the Smith–Watson–Topper (SWT) damage equation, respectively, for different specimens under different loading cases. Life prediction results showed that both equations can to some extent give reasonable results, especially within a low-cycle fatigue life regime, with the SWT damage equation giving more conservative results. As for high-cycle life, predicted results were much longer and scattered for both methods. Shell element elastic models were then used to calculate the structural stress at the periphery of the weld nuggets. The correlation between structural stress amplitude and experimental life showed the appropriateness of the structural stress fatigue evaluation for friction stir welds. The effect of the notches at the periphery of the faying surface on life prediction was further discussed.

Fatigue Life Prediction of Friction Stir Linear Welds for Magnesium Alloys

2016 ◽  
Author(s):  
HongTae Kang ◽  
Abolhassan Khosrovaneh ◽  
Xuming Su ◽  
Mingchao Guo ◽  
Yung-Li Lee ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Magnesium Alloys ◽  
Life Prediction ◽  
Fatigue Life Prediction ◽  
Friction Stir

Fatigue Life Prediction of Gear Based on Simulation Technology

2006 ◽  
Vol 324-325 ◽  
pp. 431-434
Author(s):  
Qing Bin Cui ◽  
Jing Zhu Zhang ◽  
Guan Hai Xue ◽  
Shi Chun Chen ◽  
Lei Lei
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Dynamic Load ◽  
Life Prediction ◽  
Strain State ◽  
The Self ◽  
Fatigue Life Prediction ◽  
Load Spectrum ◽  
Stress Strain ◽  
Transmission Gear

Dynamic analysis, finite element analysis and fatigue life analysis of transmission gear of Self-Propelled Gun is achieved in this paper according to the theory of multi-body dynamics, finite element and cumulative fatigue damage, and the well-known software Pro/E, ADAMS, PATRAN and FE-Fatigue are integrated in the research. The virtual prototyping model of self-propelled gun’s transmission box is built by ADAMS software. The dynamic load spectrum of transmission gear is achieved by virtual driving of Self-Propelled Gun. The finite element model of the gear is built by using PATRAN software, after defining reasonable boundary conditions, material and element properties, according to the load and the fatigue failure criterion of the gear, the stress-strain state of gear on load is studied. The dynamic load spectrum and the stress-strain state of the gear are considered as basic input data, the fatigue life of the gear is calculated by using FE-fatigue software. The road haul of gear without fault is predicted when the self-propelled gun drives on the second-class load surface at low speed. This method offers a new idea to the fatigue life prediction. It can predict fatigue life without experiments, and save cost and time. It has the great significance to the optimization design of the self-propelled gun.

scholarly journals High-Temperature Low Cycle Fatigue Life Prediction and Experimental Research of Pre-Tightened Bolts

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 828 ◽  
Author(s):  
Qingmin Yu ◽  
Honglei Zhou ◽  
Xudong Yu ◽  
Xiangjin Yang
Keyword(s):  
High Temperature ◽  
Fatigue Life ◽  
Life Prediction ◽  
Low Cycle Fatigue ◽  
Equivalent Stress ◽  
Fatigue Tests ◽  
Fatigue Life Prediction ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Fatigue Model

Bolted connections are widely used in various mechanical structures due to their superior fastening properties. However, vibration and fatigue loads in the structure are likely to cause fatigue failure of the bolted joints, especially those under high temperature, such as in aero-engines. This paper mainly studies the low-cycle fatigue life of the pre-tightened bolts working at a high temperature. A novel test fixture is designed for fatigue tests, and low cycle fatigue tests of pre-tightened bolts are conducted at the temperatures of 550 °C and 650 °C, respectively. Furthermore, a new low cycle fatigue model that is based on the Von Mises equivalent stress/strain criterion is proposed. Meanwhile, the proposed model is used to predict the high-temperature low cycle fatigue life of pre-tightened bolts according to the stress/strain results obtained by finite element analysis. There is good agreement between the experimental results and those obtained by theoretical prediction, which validates the accuracy of the proposed fatigue model. Research results will provide a theoretical basis for the low cycle fatigue life prediction of pre-tightened bolts.

A weight function method for multiaxial low-cycle fatigue life prediction under variable amplitude loading

2018 ◽  
Vol 53 (4) ◽  
pp. 197-209 ◽  
Author(s):  
Xiao-Wei Wang ◽  
De-Guang Shang ◽  
Yu-Juan Sun
Keyword(s):  
Fatigue Life ◽  
Weight Function ◽  
Life Prediction ◽  
Function Method ◽  
Low Cycle Fatigue ◽  
Fatigue Life Prediction ◽  
Cycle Fatigue ◽  
Critical Plane ◽  
Variable Amplitude ◽  
Weight Function Method

A weight function method based on strain parameters is proposed to determine the critical plane in low-cycle fatigue region under both constant and variable amplitude tension–torsion loadings. The critical plane is defined by the weighted mean maximum absolute shear strain plane. Combined with the critical plane determined by the proposed method, strain-based fatigue life prediction models and Wang-Brown’s multiaxial cycle counting method are employed to predict the fatigue life. The experimental critical plane orientation and fatigue life data under constant and variable amplitude tension–torsion loadings are used to verify the proposed method. The results show that the proposed method is appropriate to determine the critical plane under both constant and variable amplitude loadings.

An Application of Incremental Plasticity Theory to Fatigue Life Prediction of Steels

1991 ◽  
Vol 113 (4) ◽  
pp. 404-410 ◽  
Author(s):  
W. R. Chen ◽  
L. M. Keer
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Kinematic Hardening ◽  
Yield Condition ◽  
Strain Curve ◽  
Fatigue Life Prediction ◽  
304 Stainless Steel ◽  
Flow Rule ◽  
Stress Strain ◽  
Von Mises

An incremental plasticity model is proposed based on the von-Mises yield condition, associated flow rule, and nonlinear kinematic hardening rule. In the present model, fatigue life prediction requires only the uniaxial cycle stress-strain curve and the uniaxial fatigue test results on smooth specimens. Experimental data of 304 stainless steel and 1045 carbon steel were used to validate this analytical model. It is shown that a reasonable description of steady-state hysteresis stress-strain loops and prediction of fatigue lives under various combined axial-torsional loadings are given by this model

Sign in / Sign up

Export Citation Format

Share Document