Fatigue Damage Analysis of Double-Lap Bolted Joints Considering the Effects of Hole Cold Expansion and Bolt Clamping Force

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Ying Sun ◽  
George Z. Voyiadjis ◽  
Weiping Hu ◽  
Qingchun Meng ◽  
Yuanming Xu
Keyword(s):  
Fatigue Damage ◽  
Damage Mechanics ◽  
Fatigue Behavior ◽  
Continuum Damage Mechanics ◽  
Material Behavior ◽  
Bolted Joints ◽  
Clamping Force ◽  
Bolted Joint ◽  
Cold Expansion ◽  
Two Factors

Hole cold expansion and bolt clamping force are usually applied to improve the fatigue performance of bolted joints. In order to investigate the effects of hole cold expansion and bolt clamping force and reveal the mechanism of these two factors on the fatigue damage of bolted joint, a continuum damage mechanics (CDM) based approach in conjunction with the finite element method is used. The damage-coupled Voyiadjis plasticity constitutive model is used to represent the material behavior, which is implemented by user material subroutine in abaqus. The elasticity and plasticity damage evolutions of the material are described by the stress-based and plastic-strain-based equations, respectively. The fatigue damage of joint is calculated using abaqus cycle by cycle. The fatigue lives of double-lap bolted joints with and without clamping force at different levels of hole cold expansion are all obtained. The characteristics of fatigue damage corresponding to the different conditions are presented to unfold the influencing mechanism of these two factors. The predicted fatigue lives and crack initiation locations are in good agreement with the experimental results available in the literature. The beneficial effects of hole cold expansion and bolt clamping force on the fatigue behavior of bolted joint are presented in this work.

Fatigue and fretting fatigue life prediction of double-lap bolted joints using continuum damage mechanics-based approach

2016 ◽  
Vol 26 (1) ◽  
pp. 162-188 ◽  
Author(s):  
Ying Sun ◽  
George Z Voyiadjis ◽  
Weiping Hu ◽  
Fei Shen ◽  
Qingchun Meng
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Damage Mechanics ◽  
Failure Modes ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Fretting Fatigue ◽  
Bolted Joints ◽  
Continuum Damage ◽  
Bolted Joint

Fatigue and fretting fatigue are the main failure mode in bolted joints when subjected to cyclic load. Based on continuum damage mechanics, an elastic–plastic fatigue damage model and a fretting fatigue damage model are combined to evaluate the fatigue property of bolted joints to cover the two different failure modes arisen at two possible critical sites. The predicted fatigue lives agree well with the experimental results available in the literature. The beneficial effects of clamping force on fatigue life improvement of the bolted joint are revealed: part of the load is transmitted by friction force in the contact interface, and the stress amplitude at the critical position is decreased due to the reduction in the force transmitted by the bolt. The negative effect of fretting damage on the bolted joint is also captured in the simulation.

Analysis of Multi-Axial Creep–Fatigue Damage on an Outer Cylinder of a 1000 MW Supercritical Steam Turbine

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Weizhe Wang
Keyword(s):  
Steam Turbine ◽  
Fatigue Damage ◽  
Damage Mechanics ◽  
Hydrostatic Stress ◽  
Fatigue Behavior ◽  
Axial Stress ◽  
Outer Cylinder ◽  
Continuum Damage Mechanics ◽  
Transfer Coefficients ◽  
Creep Fatigue

A multi-axial continuum damage mechanics (CDM) model was proposed to calculate the multi-axial creep–fatigue damage of a high temperature component. A specific outer cylinder of a 1000 MW supercritical steam turbine was used in this study, and the interaction of the creep and fatigue behavior of the outer cylinder was numerically investigated under a startup–running–shutdown process. To this end, the multi-axial stress–strain behavior of the outer cylinder was numerically studied using Abaqus. The in-site measured temperatures were provided to validate the heat transfer coefficients, which were used to calculate the temperature field of the outer cylinder. The multi-axial mechanics behavior of the outer cylinder was investigated in detail, with regard to the temperature, Mises stress, hydrostatic stress, multi-axial toughness factor, multi-axial creep strain, and damage. The results demonstrated that multi-axial mechanics behavior reduced the total damage.

A Continuum Damage Mechanics-Based Viscoplastic Model of Adapted Complexity for High-Temperature Creep–Fatigue Loading

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Weizhe Wang ◽  
Patrick Buhl ◽  
Andreas Klenk ◽  
Yingzheng Liu
Keyword(s):  
Damage Mechanics ◽  
Fatigue Behavior ◽  
Continuum Damage Mechanics ◽  
Fatigue Loading ◽  
Material Model ◽  
Material Behavior ◽  
Continuum Damage ◽  
Loading Test ◽  
Constitutive Material Model ◽  
Creep Fatigue

A continuum damage mechanics (CDM) based viscoplastic constitutive model is established in this study to describe the fully coupling of creep and fatigue behavior. The most significant improvement is the introduction of a continuum damage variable into the constitutive equations, instead of considering creep damage and fatigue damage separately. The CDM-based viscoplastic constitutive material model is implemented using a user-defined subroutine (UMAT). A standard specimen is used for carrying out uniaxial creep, fatigue, and creep–fatigue interaction tests to validate the material model. In addition, to further demonstrate the capability of the material model to predict the complex material behavior, a complex strain-control loading test is performed to validate the material model. The simulated and measured results are in good agreement at different temperatures and loadings, in particular for rapid cyclic softening behavior following crack initiation and propagation.

Modeling of the Strain Rate Dependent Material Behavior of 3D-Textile Composites with Production and Operational Defects

2011 ◽  
Vol 403-408 ◽  
pp. 651-655
Author(s):  
W. Hufenbach ◽  
M. Gude ◽  
R. Protz
Keyword(s):  
Strain Rate ◽  
Damage Mechanics ◽  
Additive Model ◽  
Experimental Tests ◽  
Continuum Damage Mechanics ◽  
Textile Composites ◽  
Material Behavior ◽  
Rate Dependent ◽  
Dynamic Tensile Loading ◽  
Good Coincidence

This paper concerned with modeling of the strain rate dependent material behavior of 3D-textile composites with simultaneous consideration of production and operational (e.g. pores or fatigue damage) defects. Therefore an additive model in the sense of continuum damage mechanics was introduced. For the model validation extensive experimental tests on glass non-crimp fabrics reinforced epoxy (GF-NCF/EP) composites are performed. The focus is put on the influence of production and fatigue related pre-damage under subsequent highly-dynamic tensile loading. The theoretical studies shows a good coincidence with the experimentally results

scholarly journals Life analysis of the bolted joint

2019 ◽  
Vol 254 ◽  
pp. 02004
Author(s):  
Milan Sapieta ◽  
Peter Sulka
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Analysis ◽  
Fatigue Damage ◽  
Computational Models ◽  
Bolted Joints ◽  
Bolted Joint ◽  
Computation Model ◽  
Life Analysis ◽  
Element Method

The paper deals with the fatigue damage calculation of 2 types of computation model of bolted joints. The study is performed via a numerical analysis with support of finite element method (FEM) software ANSYS. One model was created with a thread on the bolt, another was only bolt with cylindrical surfaces, the second model was greatly simplified. It will be evaluated the fatigue damage for both types of models. Subsequently both types of computational models will be compared in dependence on the accuracy of the results and the speed of the calculation. There are also the theoretical backgrounds for preloaded bolted joint, which was used for calculation of preload load prescribed on body of screws.

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