Due to traffic and wave actions, cast steel joints are subjected to variable-amplitude fatigue loading, which may cause fatigue problems. The ratio of the minimum strain to the maximum strain(strain ratio)can be emplo...Due to traffic and wave actions, cast steel joints are subjected to variable-amplitude fatigue loading, which may cause fatigue problems. The ratio of the minimum strain to the maximum strain(strain ratio)can be employed to analyze the influence of variable-amplitude fatigue both in the elastic and plastic ranges. To evaluate the effect of the strain ratio on G20Mn5 QT cast steel, the fatigue tests of smooth specimens were carried out at the strain ratio of 0.1. The cyclic deformation and the relationships between the strain amplitude, the stress amplitude, the Smith, Watson and Topper(SWT)parameter and fatigue life were studied and compared with those at the strain ratio of-1. Compared with other methods, Basquin formula and Solonberg formula provide reliable and appropriate ranges of S-N curve and fatigue limit at different strain ratios respectively. The SWT parameter can be used to predict the fatigue life at other strain ratios accurately.展开更多
Owing to the remarkable advantages in mechanical behavior,cast steel nodes have been widely used in static structures.Nowadays,cast steel nodes also gain increasing popularity due to the superior fatigue performance i...Owing to the remarkable advantages in mechanical behavior,cast steel nodes have been widely used in static structures.Nowadays,cast steel nodes also gain increasing popularity due to the superior fatigue performance in dynamic structures,but they are not yet widely used because the fatigue properties of cast steel are not well understood.In this paper,the fatigue test of cast steel GS20Mn5V commonly used in steel castings is carried out.The strength of medium and low cycle fatigue and the fatigue limit are obtained.The feasibility of the estimated S-N(fatigue stress versus life)curve is tested.The double logarithmic linear model(DLLM)and the reversed generalized Pareto model(RGPM)are used to fit the experimental data,and the comparison is made.The P-S-N(the relationship between fatigue stress and life at different survival rates)curve obtained by the RGPM is proposed.The results show that the estimated S-N curve is not suitable for low cycle fatigue life,fitting the experimental data with the RGPM is the best,and obtaining the P-S-N curve from the RGPM is feasible.展开更多
基金Supported by the National Natural Science Foundation of China(No.51178307 and No.51525803)
文摘Due to traffic and wave actions, cast steel joints are subjected to variable-amplitude fatigue loading, which may cause fatigue problems. The ratio of the minimum strain to the maximum strain(strain ratio)can be employed to analyze the influence of variable-amplitude fatigue both in the elastic and plastic ranges. To evaluate the effect of the strain ratio on G20Mn5 QT cast steel, the fatigue tests of smooth specimens were carried out at the strain ratio of 0.1. The cyclic deformation and the relationships between the strain amplitude, the stress amplitude, the Smith, Watson and Topper(SWT)parameter and fatigue life were studied and compared with those at the strain ratio of-1. Compared with other methods, Basquin formula and Solonberg formula provide reliable and appropriate ranges of S-N curve and fatigue limit at different strain ratios respectively. The SWT parameter can be used to predict the fatigue life at other strain ratios accurately.
基金the National Key Research and Development Program of China(No.2017YFC0805100)the National Natural Science Foundation of China(No.51578137)+1 种基金the Priority Academic Program Development of the Jiangsu Higher Education Institutionsthe Open Research Fund Program of Jiangsu Key Laboratory of Engineering Mechanics。
文摘Owing to the remarkable advantages in mechanical behavior,cast steel nodes have been widely used in static structures.Nowadays,cast steel nodes also gain increasing popularity due to the superior fatigue performance in dynamic structures,but they are not yet widely used because the fatigue properties of cast steel are not well understood.In this paper,the fatigue test of cast steel GS20Mn5V commonly used in steel castings is carried out.The strength of medium and low cycle fatigue and the fatigue limit are obtained.The feasibility of the estimated S-N(fatigue stress versus life)curve is tested.The double logarithmic linear model(DLLM)and the reversed generalized Pareto model(RGPM)are used to fit the experimental data,and the comparison is made.The P-S-N(the relationship between fatigue stress and life at different survival rates)curve obtained by the RGPM is proposed.The results show that the estimated S-N curve is not suitable for low cycle fatigue life,fitting the experimental data with the RGPM is the best,and obtaining the P-S-N curve from the RGPM is feasible.
