DESIGNING OF A TESTING MACHINE FOR SHEAR-MODE FATIGUE CRACK GROWTH

2012 ◽  
Vol 06 ◽  
pp. 318-323
Author(s):  
A. KUSABA ◽  
S. OKAZAKI ◽  
M. ENDO ◽  
K. YANASE
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
High Performance ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Shear Mode ◽  
Mode Iii ◽  
Research Activity ◽  
Testing Speed

As recognized, flaking-type failure is one of the serious problems for railroad tracks and bearings. In essence, flaking-type failure is closely related to the growth of the shear-mode (Mode-II and Mode-III) fatigue crack. In our research group, it is demonstrated that a shear-mode fatigue crack can be reproduced for cylindrical specimens by applying the cyclic torsion in the presence of the static axial compressive stress. However, a biaxial servo-hydraulic fatigue testing machine is quite expensive to purchase and costly to maintain. The low testing speed (about 10Hz) of the testing machine further aggravates the situation. As a result, study on shear-mode fatigue crack growth is still in the nascent stage. To overcome the difficulties mentioned above, in this research activity, we developed a high-performance and cost-effective testing machine to reproduce the shear-mode fatigue crack growth by improving the available resonance-type torsion fatigue testing machine. The primary advantage of using the resonance-type torsion fatigue testing machine is cost-efficiency. In addition, the testing speed effectively can be improved, in comparison with that of a biaxial servo-hydraulic fatigue testing machine. By utilizing the newly-designed testing machine, we have demonstrated that we can successfully reproduce the shear-mode fatigue crack.

Study on Fatigue Crack Growth Rate of Welded Joint of Duplex Stainless Steel

2011 ◽  
Vol 291-294 ◽  
pp. 941-944
Author(s):  
Zheng Lun Wang ◽  
Zhi Xiang Wang
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Duplex Stainless Steel ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Fatigue Testing ◽  
Testing Machine

The fatigue crack growth behavior of weld metal (WM), heat affected zone(HAZ) and base metal(BM) of Duplex Stainless Steel 2205(DSS) has been determined at high-frequency fatigue testing machine. The results show that the fatigue crack growth rate of WM is slowest and the ability to resist fatigue crack growth is highest in the three parts. Secondly, the sensitivity caused by the stress change of WM is the highest, followed by HAZ, and the BM is the weakest.

Study on Fatigue Crack Behavior in Welded Structure of DSS 2205

2012 ◽  
Vol 503-504 ◽  
pp. 991-994
Author(s):  
Zhi Xiang Wang ◽  
Zheng Lun Wang ◽  
Xin Zhang
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Regression Equations ◽  
Welded Structure

The fatigue crack growth behavior of weld metal (WM), heat affected zone (HAZ) and base metal(BM) of Duplex Stainless Steel (DSS) 2205 standard sample was tested in different stress ratios at HF fatigue testing machine. ANSYS analysis software was used to simulate the fatigue crack growth rate of the steel under different stress ratio. Regression equations and da / dK-ΔK curves of experiment and simulation are compared and analyzed. The results show that the fatigue crack growth rate of WM is slowest and the ability to resist fatigue crack growth is highest among the three parts, the lowest is BM. Secondly, the sensitivity of the rate caused by the stress change of WM is the highest, and the lowest is BM. The simulation of fatigue crack growth rate of DSS 2205 is completely correct and feasible by the experiment.

scholarly journals SVR Prediction Algorithm for Crack Propagation of Aviation Aluminum Alloy

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jincai Chang ◽  
Zhihang Wang ◽  
Qingyu Zhu ◽  
Zhao Wang
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Length ◽  
Crack Growth ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Prediction Algorithm ◽  
Support Vector ◽  
Alloy Plate

Aluminum alloy material is an important component material in the safe flight of aircraft. It is very important and necessary to predict the fatigue crack growth between holes of aviation aluminum alloy materials. At present, the investigation on the prediction of the cracks between two holes and multiholes is a key problem to be solved. Due to the fact that the fatigue crack growth test of aluminum alloy plate with two or three holes was carried out by the MTS fatigue testing machine, the crack length growth data under different test conditions were obtained. In this paper, support vector regression (SVR) was used to fit the crack data, and the parameters of SVR are optimized by the grid search algorithm at the same time. And then the model of SVR to predict the crack length was established. Discussion on the results shows that the prediction model is effective. Furthermore, the crack growth between three holes was predicted accurately through the model of the crack law between two holes under the same load form.

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