Fatigue Life Prediction of Spring Buffer in GCD-1500 Cable Drill

2010 ◽  
Vol 118-120 ◽  
pp. 820-824
Author(s):  
Chang Gen Bu ◽  
Bo Long ◽  
J.W. Li ◽  
L. Wang
Keyword(s):  
Fatigue Life ◽  
Dynamic Response ◽  
Dynamic Simulation ◽  
Fatigue Damage ◽  
Hybrid Model ◽  
Life Prediction ◽  
Fatigue Life Prediction ◽  
Dynamic Responses ◽  
Load Spectrum ◽  
Impact Mechanism

Conventionally designed with quasi-static algorithm, buffer springs of impact mechanism eventually have a short fatigue life. By building a rigid-flexible hybrid model of GCD-1500 cable drill, the main fatigue causes of buffer springs are investigated so as to optimize the design of springs attached to impact mechanism. Dynamic simulation is used to export load spectrum of dynamic responses of springs in conditions of “idle impact” and different bore depths. Nominal stress method is employed in nSoft Software to analyze the fatigue of springs. Some crucial conclusions are drawn: the fatigue damage brought by load spectrum of dynamic response is more severe than that brought by quasi-static mono-pulse circulation; as the bore depth is prolonged, the damage of one impact will increase; the damage of “idle impact” is 25 times as serious as that of one impact when bore depth is 70m.

scholarly journals Strain energy-based rubber fatigue life prediction under the influence of temperature

2018 ◽  
Vol 5 (10) ◽  
pp. 180951 ◽  
Author(s):  
Jingnan Zhang ◽  
Fengxian Xue ◽  
Yue Wang ◽  
Xin Zhang ◽  
Shanling Han
Keyword(s):  
Fatigue Life ◽  
Prediction Model ◽  
Fatigue Damage ◽  
Strain Energy ◽  
Life Prediction ◽  
Least Square ◽  
Fatigue Life Prediction ◽  
Uniaxial Tensile ◽  
Influence Of Temperature ◽  
Different Temperatures

Aiming at the problem of the fatigue life prediction of rubber under the influence of temperature, the effects of thermal ageing and fatigue damage on the fatigue life of rubber under the influence of temperature are analysed and a fatigue life prediction model is established by selecting strain energy as a fatigue damage parameter based on the uniaxial tensile data of dumbbell rubber specimens at different temperatures. Firstly, the strain energy of rubber specimens at different temperatures is obtained by the Yeoh model, and the relationship between it and rubber fatigue life at different temperatures is fitted by the least-square method. Secondly, the function formula of temperature and model parameters is obtained by the least-square polynomial fitting. Finally, another group of rubber specimens is tested at different temperatures and the fatigue characteristics are predicted by using the proposed prediction model under the influence of temperature, and the results are compared with the measured results. The results show that the predicted value of the model is consistent with the measured value and the average relative error is less than 22.26%, which indicates that the model can predict the fatigue life of this kind of rubber specimen at different temperatures. What's more, the model proposed in this study has a high practical value in engineering practice of rubber fatigue life prediction at different temperatures.

Determination Method of a Proper Small-Load-Omitting Criterion Based on the Extreme Load

2013 ◽  
Vol 694-697 ◽  
pp. 278-283
Author(s):  
Zhi Qiang Xu
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
High Frequency ◽  
Life Prediction ◽  
Time History ◽  
Fatigue Life Prediction ◽  
Threshold Theory ◽  
Small Load ◽  
Extreme Load ◽  
Peak Over Threshold

A crucial step to obtain a reliable fatigue life prediction is to determine a proper small load threshold below which the cycles at small loads or stresses with high frequency causing little fatigue damage are truncated from the original load time history. By taking both the peak over threshold theory and the endurance limit threshold into account, a proper small load threshold is proposed in this paper. The optimal threshold should be high enough to remove the high-frequency small cycles and low enough to minimize the loss of the fatigue damage which maybe be truncated by the empirical small-load omitting threshold. Based on this proper threshold, the fatigue life prediction will be more reliable.

Fatigue Life Prediction of Composite Laminate

2012 ◽  
Vol 472-475 ◽  
pp. 591-595 ◽  
Author(s):  
Jun Liu ◽  
Feng Peng Zhang
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Composite Laminates ◽  
Life Prediction ◽  
Plate Theory ◽  
Damage Model ◽  
Prediction Method ◽  
Fatigue Life Prediction ◽  
Fatigue Properties ◽  
Adjacent Layer

Abstract. based on the accumulating fatigue damage model, with single ply plate theory and experiment data as the foundation, consider the interaction between adjacent layer and material degradation, a kind of fatigue life prediction method of fiber reinforced composite laminates is developed. The stiffness decline of each ply during cyclic loading is determined by the fatigue damage variable and the load amplitude and the fatigue life of any laminates can be predicted using the fatigue properties of single ply plate. Using this method a 3D Finite element model is established by ABAQUS software and the fatigue life and the fatigue damage evolution of a T300 / QY8911 laminats are analyzed, the results are more closer to the experimental results.

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