scholarly journals Modeling of fatigue damage accumulation in multiple contact of pre-stressed bodies in the presence of wear

2020 ◽  
pp. 78-88
Author(s):  
Ирина Георгиевна Горячева ◽  
Елена Владимировна Торская
Keyword(s):  
Shear Stress ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Residual Stresses ◽  
Fatigue Damage ◽  
Damage Accumulation ◽  
Rolling Contact ◽  
Surface Wear ◽  
Fatigue Damage Accumulation ◽  
Relative Slippage

Рассматривается влияние остаточных напряжений, формирующихся при различных видах поверхностной обработки элементов пар трения, на скорость накопления контактно-усталостных повреждений, возникающих при циклическом нагружении поверхностей взаимодействующих тел в условиях трения качения при наличии поверхностного изнашивания. Исследовано влияние относительного проскальзывания, коэффициента трения скольжения, величины остаточных напряжений на распределение амплитудных значений максимальных касательных напряжений. Полученные результаты использованы для анализа влияния поля остаточных напряжений и скорости поверхностного изнашивания на процесс накопления контактно-усталостных повреждений. Residual stresses are formed during various types of surface treatment of elements of friction pairs. The effect of the residual stresses on the rate of fatigue damage accumulation is considered for the case of cyclic rolling contact in the presence of surface wear. The effect of relative slippage, friction coefficient, and residual stresses on the distribution of the amplitude values of the principal shear stress is studied. The results are used to analyze the effect of the residual stresses and the surface wear rate on the fatigue damage accumulation.

Research on the Approach for the Assessment of Subsurface Rolling Contact Fatigue Damage

2013 ◽  
Vol 395-396 ◽  
pp. 845-851
Author(s):  
Xiao Feng Qin ◽  
Da Le Sun ◽  
Li Yang Xie
Keyword(s):  
Shear Stress ◽  
Friction Coefficient ◽  
Fatigue Damage ◽  
Stress Ratio ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Critical Stresses ◽  
Orthogonal Shear Stress

In this paper, the distribution of different critical stresses, which were used in previous correlation articles for the assessment of subsurface rolling contact fatigue damage, was analyzed. The rationality of orthogonal shear stress was selected as the key stress controlling the subsurface rolling contact fatigue damage was clarified. Base on the linear fatigue damage accumulative theory and the modification equation for the range of asymmetrical stress, the influence of friction on subsurface rolling contact fatigue damage was studied. The results show that the subsurface orthogonal shear stress is a completely symmetrical stress when the friction coefficient is zero, while it is an asymmetrical stress with considering the friction. The stress ratio of subsurface orthogonal shear stress and subsurface rolling contact fatigue damage is increased with the increasing of friction.

scholarly journals Numerical Study on Vibration Response and Fatigue Damage of Axial Compressor Blade Considering Aerodynamic Excitation

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1835
Author(s):  
Xi Fu ◽  
Chao Ma ◽  
Jiewei Lin ◽  
Junhong Zhang
Keyword(s):  
Shear Stress ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
Damage Accumulation ◽  
Equivalent Stress ◽  
Axial Compressor ◽  
Compressor Blade ◽  
Torsional Shear ◽  
Fatigue Damage Accumulation ◽  
Fatigue Model

Axial compressor blades with a deformed initial torsion angle caused by aerodynamic excitation resonated at the working speed and changed the rule of fatigue damage accumulation. The fatigue life of a blade has a prediction error, even causing serious flight accidents if the effect of torque causing damage deterioration of the blade fatigue life is neglected. Therefore, in this paper, a uniaxial non-linear fatigue damage model was modified using the equivalent stress with torsional shear stress, and the proposed fatigue model including the torsional moment was used to study the compressor blade fatigue life. Then, the blade numerical simulation model was established to calculate the vibration characteristics under complex loads of airflow excitation and a rotating centrifugal force. Finally, the blade fatigue life under actual working conditions was predicted using the modified fatigue model. The results show that the interaction between centrifugal and aerodynamic loads affects the natural frequency, as the frequencies in modes dominated by bending deformation decreased whereas those dominated by torsional deformation increased. Furthermore, the blade root of the suction surface showed stress concentration, but there is an obvious difference of stress distribution and amplitude between the normal stress and the equivalent stress including torsional shear stress. The additional consideration of the torsional shear stress decreased the predicted fatigue life by 4.5%. The damage accumulation rate changes with the loading cycle, and it accelerates fast for the last 25% of the cycle, when the blade fracture may occur at any time. Thus, the aerodynamic excitation increased the safety factor of blade fatigue life prediction.

Fatigue damage accumulation around notches

2004 ◽  
Vol 46 (6) ◽  
pp. 309-313
Author(s):  
Yutaka Iino ◽  
Hideo Yano
Keyword(s):  
Fatigue Damage ◽  
Damage Accumulation ◽  
Fatigue Damage Accumulation

Different Fatigue Dynamics Under Statistically and Spectrally Similar Deterministic and Stochastic Excitations

2013 ◽  
Vol 81 (4) ◽  
Author(s):  
Son Hai Nguyen ◽  
Mike Falco ◽  
Ming Liu ◽  
David Chelidze
Keyword(s):  
Crack Growth ◽  
Fatigue Damage ◽  
Damage Accumulation ◽  
Growth Dynamics ◽  
Experimental System ◽  
Counting Method ◽  
Random Loading ◽  
Stochastic Excitations ◽  
Fatigue Damage Accumulation ◽  
System Coupling

Estimating and tracking crack growth dynamics is essential for fatigue failure prediction. A new experimental system—coupling structural and crack growth dynamics—was used to show fatigue damage accumulation is different under chaotic (i.e., deterministic) and stochastic (i.e., random) loading, even when both excitations possess the same spectral and statistical signatures. Furthermore, the conventional rain-flow counting method considerably overestimates damage in case of chaotic forcing. Important nonlinear loading characteristics, which can explain the observed discrepancies, are identified and suggested to be included as loading parameters in new macroscopic fatigue models.

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