Estimation of Cyclic Strain Hardening Exponent and Cyclic Strength Coefficient of Steels by Artificial Neural Networks

Author(s):  
R. Ghajar ◽  
J. Alizadeh K. ◽  
N. Naserifar

The objective of this paper is to demonstrate the applicability of artificial neural networks on estimation of the cyclic strain hardening exponent and cyclic strength coefficient of steels on the basis of monotonic tensile tests properties. In order to demonstrate this applicability, steels tensile data was extracted from the literatures and two separate neural networks was conducted. One set of data was used for training networks and remaining of data for testing them. The regression analysis was used to check the system accuracy for training and test data at the end of learning. Comparing results of neural networks with values obtained from direct fitting of experimental data was indicated that cyclic strain hardening exponent and cyclic strength coefficient, which characterize the stable curves of true stress amplitude versus true plastic strain amplitude, were predicted reasonable. It was concluded that predicted stable cyclic true stress-strain curve properties by trained neural network are more accurate compared to approximate relations based on low-cycle fatigue properties.

2014 ◽  
Vol 664 ◽  
pp. 28-33
Author(s):  
Ying Lan ◽  
Li Jia Chen ◽  
Xin Che ◽  
Feng Li

The low-cycle fatigue behaviors of as-extruded and T6 treated Al-6Zn-2.5Mg-2Cu-0.1Zr-0.1Sc alloys at room temperature have been investigated under those total-strain amplitudes ranged from 0.3% to 1.0%, and the influence of T6 treatment on the low-cycle fatigue properties of Al-6Zn-2.5Mg-2Cu-0.1Zr-0.1Sc alloy was clarified. The experimental results show that during fatigue deformation, the significant cyclic strain hardening and stable cyclic stress response can be noted for both as-extruded and T6 treated Al-6Zn-2.5Mg-2Cu-0.1Zr-0.1Sc alloys. The fatigue life of as-extruded Al-6Zn-2.5Mg-2Cu-0.1Zr-0.1Sc alloy at all strain amplitudes is longer than that of the alloy subjected to T6 aging treatment. The relationship between both elastic and plastic strain amplitudes with reversals to failure shows a monotonic linear behavior, and can be described by the Basquin and Coffin-Manson equations, respectively. The T6 treatment can significantly increase the cyclic strain hardening exponent and cyclic strength coefficient of extruded Al-6Zn-2.5Mg-2Cu-0.1Zr-0.1Sc alloy.


2016 ◽  
Vol 250 ◽  
pp. 175-181 ◽  
Author(s):  
Tomasz Slezak ◽  
Lucjan Sniezek ◽  
Janusz Torzewski ◽  
Volodymyr Hutsaylyuk

The article presents the results of research on low cycle fatigue strength of high-strength structural steel S960QL. During the tests, controlled force was applied using the different total strain amplitude εac and strain ratio Rε = 0.1. The obtained results allowed to determine the value of the cyclic strain hardening exponent n' and the cyclic strength coefficient K' and to draw the cyclic stress-strain curve. Analysis was also carried out of fatigue life based on the Manson-Coffin-Basquin equation. Fatigue values were also determined. Fractographic tests of fatigue fractures allowed to identify the causes of crack initiation and the course of their propagation.


Author(s):  
Kobiljon Kh. Zoidov ◽  
◽  
Svetlana V. Ponomareva ◽  
Daniel I. Serebryansky ◽  
◽  
...  

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