The feasibility of longer spans relies on the successful implementation of new high-strength light weight materials such as carbon fiber reinforced polymer(CFRP). First, a dimensionless equilibrium equation and the co...The feasibility of longer spans relies on the successful implementation of new high-strength light weight materials such as carbon fiber reinforced polymer(CFRP). First, a dimensionless equilibrium equation and the corresponding compatibility equation are established to develop the cable force equation and cable displacement governing equation for suspension cables, respectively. Subsequently, the inextensible cable case is introduced. The formula of the Irvine parameter is considered and its physical interpretation as well as its relationship with the chord gravity stiffness is presented. The influences on the increment of cable force and displacement by λ2 and load ratio p′ are analyzed, respectively. Based on these assumptions and the analytical formulations, a 2000 m span suspension cable is utilized as an example to verify the proposed formulation and the responses of the relative increment of cable force and cable displacement under symmetrical and asymmetrical loads are studied and presented. In each case, the deflections resulting from elastic elongation or solely due to geometrical displacement are analyzed for the lower elastic modulus CFRP. Finally, in comparison with steel cables, the influences on the cable force equation and the governing displacement equation by span and rise span ratio are analyzed. Moreover, the influences on the static performance of suspension bridge by span and sag ratios are also analyzed. The substantive characteristics of the static performance of super span CFRP suspension bridges are clarified and the superiority and the characteristics of CFRP cable structure are demonstrated analytically.展开更多
Carbon fiber reinforced polymer(CFRP)has many remarkable merits.It is lightweight and has great rigidity and high intensity. High-durability cable produced from CFRP as reinforcement material is widely used in bridge ...Carbon fiber reinforced polymer(CFRP)has many remarkable merits.It is lightweight and has great rigidity and high intensity. High-durability cable produced from CFRP as reinforcement material is widely used in bridge construction projects.However, there is a dearth of studies regarding damage types and mechanism under fatigue load of CFRP bridge cables.In this paper,we adopt acoustic emission(AE)technology to monitor fatigue damage and failure of the CFRP bridge cables,specifically by monitoring the bridge cable’s fatigue test process and using wavelet transformation to analyze data.Results show that damage on the CFRP cable is divided into three stages.Based on wavelet singularity theory,in each stage of AE,the burst signal is obtained and its time-frequency distribution is achieved through wavelet analysis.According to the analysis results,failure modes in each phase and type of acoustic emission source are easy to determine.The characteristics of waveform,types of damages, and frequency distribution of CFRP bridge cable in different damage phases are collected.Research shows that the method used to determine the types of fatigue damage on the CFRP cable is feasible according to the range of distribution characteristic parameters for acoustic emission signal and type of waveform.展开更多
基金Project(2010-K2-8)supported by Science and Technology Program of the Ministry of Housing and Urban Rural Development,ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘The feasibility of longer spans relies on the successful implementation of new high-strength light weight materials such as carbon fiber reinforced polymer(CFRP). First, a dimensionless equilibrium equation and the corresponding compatibility equation are established to develop the cable force equation and cable displacement governing equation for suspension cables, respectively. Subsequently, the inextensible cable case is introduced. The formula of the Irvine parameter is considered and its physical interpretation as well as its relationship with the chord gravity stiffness is presented. The influences on the increment of cable force and displacement by λ2 and load ratio p′ are analyzed, respectively. Based on these assumptions and the analytical formulations, a 2000 m span suspension cable is utilized as an example to verify the proposed formulation and the responses of the relative increment of cable force and cable displacement under symmetrical and asymmetrical loads are studied and presented. In each case, the deflections resulting from elastic elongation or solely due to geometrical displacement are analyzed for the lower elastic modulus CFRP. Finally, in comparison with steel cables, the influences on the cable force equation and the governing displacement equation by span and rise span ratio are analyzed. Moreover, the influences on the static performance of suspension bridge by span and sag ratios are also analyzed. The substantive characteristics of the static performance of super span CFRP suspension bridges are clarified and the superiority and the characteristics of CFRP cable structure are demonstrated analytically.
基金supported by the National Natural Science Foundation of China(Grant No.50808030)the Doctoral Fund of Ministry of Education of China(Grant No.200801411102)
文摘Carbon fiber reinforced polymer(CFRP)has many remarkable merits.It is lightweight and has great rigidity and high intensity. High-durability cable produced from CFRP as reinforcement material is widely used in bridge construction projects.However, there is a dearth of studies regarding damage types and mechanism under fatigue load of CFRP bridge cables.In this paper,we adopt acoustic emission(AE)technology to monitor fatigue damage and failure of the CFRP bridge cables,specifically by monitoring the bridge cable’s fatigue test process and using wavelet transformation to analyze data.Results show that damage on the CFRP cable is divided into three stages.Based on wavelet singularity theory,in each stage of AE,the burst signal is obtained and its time-frequency distribution is achieved through wavelet analysis.According to the analysis results,failure modes in each phase and type of acoustic emission source are easy to determine.The characteristics of waveform,types of damages, and frequency distribution of CFRP bridge cable in different damage phases are collected.Research shows that the method used to determine the types of fatigue damage on the CFRP cable is feasible according to the range of distribution characteristic parameters for acoustic emission signal and type of waveform.
