Fatigue cracking is one of the principal failure modes of asphalt pavement. The chief factors affecting the fatiguefailure of asphalt pavement are load, environment, pavement structure and the fatigue resistance of as...Fatigue cracking is one of the principal failure modes of asphalt pavement. The chief factors affecting the fatiguefailure of asphalt pavement are load, environment, pavement structure and the fatigue resistance of asphaltmixture itself. Among them, the most important part is the research on the fatigue resistance of asphalt mixture,which has been studied deeply at home and abroad. This paper summarized some important research results andfatigue characterization parameters of the four-point bending fatigue test method in recent years, and suggestedthe future research direction of the four-point bending test. In the analysis and comparison of loading modes offour-point bending test, further research on various analysis methods is required. Researchers can appropriatelyrefine the test method to account for nonlinear viscoelastic energy dissipation, as well as plastic and permanentdeformation per cycle. The fatigue evaluation index of asphalt mixture can be comprehensively evaluated by fourindicators, and can be combined with new fatigue characterization parameters in the future. It is suggested todevelop a complete set of four-point bending fatigue test methods under various stress states consistent with theservice state of asphalt pavement. This method can be used to eliminate the influences of environment, testcondition and specimen size on the fatigue test results of asphalt mixture to improve the effectiveness andcompleteness of asphalt mixture fatigue performance characterization.展开更多
The four-level active neutral point clamped(ANPC)inverter has become increasingly widely used in the renewable energy indus-try since it offers one more voltage level without increasing the total number of active swit...The four-level active neutral point clamped(ANPC)inverter has become increasingly widely used in the renewable energy indus-try since it offers one more voltage level without increasing the total number of active switches compared to the three-level ANPC inverter.The model predictive current control(MPCC)is a promising control method for multi-level inverters.However,the conven-tional MPCC suffers from high computational complexity and tedious weighting factor tuning in multi-level inverter applications.A low-complexity MPCC without weighting factors for a four-level ANPC inverter is proposed in this paper.The computational burden and voltage vector candidate set are reduced according to the relationship between voltage vector and neutral point voltage balance.The proposed MPCC shows excellent steady-state and dynamics performances while ensuring the neutral point voltage balancing.The efficacy of the proposed MPCC is verified by simulation and experimental results.展开更多
基金financial supported by Natural Science Foundation of Guangxi Province(award number:2021JJA160140).
文摘Fatigue cracking is one of the principal failure modes of asphalt pavement. The chief factors affecting the fatiguefailure of asphalt pavement are load, environment, pavement structure and the fatigue resistance of asphaltmixture itself. Among them, the most important part is the research on the fatigue resistance of asphalt mixture,which has been studied deeply at home and abroad. This paper summarized some important research results andfatigue characterization parameters of the four-point bending fatigue test method in recent years, and suggestedthe future research direction of the four-point bending test. In the analysis and comparison of loading modes offour-point bending test, further research on various analysis methods is required. Researchers can appropriatelyrefine the test method to account for nonlinear viscoelastic energy dissipation, as well as plastic and permanentdeformation per cycle. The fatigue evaluation index of asphalt mixture can be comprehensively evaluated by fourindicators, and can be combined with new fatigue characterization parameters in the future. It is suggested todevelop a complete set of four-point bending fatigue test methods under various stress states consistent with theservice state of asphalt pavement. This method can be used to eliminate the influences of environment, testcondition and specimen size on the fatigue test results of asphalt mixture to improve the effectiveness andcompleteness of asphalt mixture fatigue performance characterization.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB4201602)the National Natural Science Foundation of China(Grant No.52002409).
文摘The four-level active neutral point clamped(ANPC)inverter has become increasingly widely used in the renewable energy indus-try since it offers one more voltage level without increasing the total number of active switches compared to the three-level ANPC inverter.The model predictive current control(MPCC)is a promising control method for multi-level inverters.However,the conven-tional MPCC suffers from high computational complexity and tedious weighting factor tuning in multi-level inverter applications.A low-complexity MPCC without weighting factors for a four-level ANPC inverter is proposed in this paper.The computational burden and voltage vector candidate set are reduced according to the relationship between voltage vector and neutral point voltage balance.The proposed MPCC shows excellent steady-state and dynamics performances while ensuring the neutral point voltage balancing.The efficacy of the proposed MPCC is verified by simulation and experimental results.
