Through the static tensile test of Q690 high-strength steel, the relevant mechanical parameters are obtained and the maximum fatigue load is determined. The fatigue life is measured by the fatigue test under the load....Through the static tensile test of Q690 high-strength steel, the relevant mechanical parameters are obtained and the maximum fatigue load is determined. The fatigue life is measured by the fatigue test under the load. According to the fatigue cumulative damage method, the number of fatigue pre-damage vibration is designed in proportion. Then the fatigue pre-damage test is carried out on the high-strength steel, the stress-strain curve and the variation of residual mechanical property reduction coefficient with fatigue damage were drawn. The results show that: compared with the undamaged specimens, the yield strength and tensile strength of Q690 steel are less affected by fatigue damage, but the elongation changes more significantly, and the elastic modulus is not significantly affected. Finally, through the change of mechanical properties of Q690 high-strength steel with different fatigue damage, it provides a scientific basis for the performance evaluation of existing Q690 high-strength steel structure after fatigue damage.展开更多
The cast aluminum beam is a key structure for carrying the body-hung traction motor of a high-speed train;its fatigue property is fundamental for predicting the residual life and service mileage of the structure.To ch...The cast aluminum beam is a key structure for carrying the body-hung traction motor of a high-speed train;its fatigue property is fundamental for predicting the residual life and service mileage of the structure.To characterize the structural fatigue property,a finite element-based method is developed to compute the stress concentration factor,which is used to obtain the structural fatigue strength reduction factors.A full-scale fatigue test on the cast aluminum beam is designed and implemented for up to ten million cycles,and the corresponding finite element model of the beam is validated using the measured data of the gauges.The results show that the maximum stress concentration occurs at the fillet of the supporting seat,where the structural fatigue strength reduction factor is 2.45 and the calculated fatigue limit is 35.4 MPa.Moreover,no surface cracks are detected using the liquid penetrant test.Both the experimental and simulation results indicate that the cast aluminum beam can satisfy the service life requirements under the designed loading conditions.展开更多
文摘Through the static tensile test of Q690 high-strength steel, the relevant mechanical parameters are obtained and the maximum fatigue load is determined. The fatigue life is measured by the fatigue test under the load. According to the fatigue cumulative damage method, the number of fatigue pre-damage vibration is designed in proportion. Then the fatigue pre-damage test is carried out on the high-strength steel, the stress-strain curve and the variation of residual mechanical property reduction coefficient with fatigue damage were drawn. The results show that: compared with the undamaged specimens, the yield strength and tensile strength of Q690 steel are less affected by fatigue damage, but the elongation changes more significantly, and the elastic modulus is not significantly affected. Finally, through the change of mechanical properties of Q690 high-strength steel with different fatigue damage, it provides a scientific basis for the performance evaluation of existing Q690 high-strength steel structure after fatigue damage.
基金Supported by the National Natural Science Foundation of China(Grant No.51475036)the International Cooperation and Exchange of the National Natural Science Foundation of China(Grant No.51711530034).
文摘The cast aluminum beam is a key structure for carrying the body-hung traction motor of a high-speed train;its fatigue property is fundamental for predicting the residual life and service mileage of the structure.To characterize the structural fatigue property,a finite element-based method is developed to compute the stress concentration factor,which is used to obtain the structural fatigue strength reduction factors.A full-scale fatigue test on the cast aluminum beam is designed and implemented for up to ten million cycles,and the corresponding finite element model of the beam is validated using the measured data of the gauges.The results show that the maximum stress concentration occurs at the fillet of the supporting seat,where the structural fatigue strength reduction factor is 2.45 and the calculated fatigue limit is 35.4 MPa.Moreover,no surface cracks are detected using the liquid penetrant test.Both the experimental and simulation results indicate that the cast aluminum beam can satisfy the service life requirements under the designed loading conditions.
