A timely and accurate damage identification for bridge structures is essential to prevent sudden failures/collapses and other catastrophic accidents.Based on response surface model(RSM)updating and element modal strai...A timely and accurate damage identification for bridge structures is essential to prevent sudden failures/collapses and other catastrophic accidents.Based on response surface model(RSM)updating and element modal strain energy(EMSE)damage index,this paper proposes a novel damage identification method for girder bridge structures.The effectiveness of the proposed damage identification method is investigated using experiments on four simply supported steel beams.With Xiabaishi Bridge,a prestressed continuous rigid frame bridge with large span,as the engineering background,the proposed damage identification method is validated by using numerical simulation to generate different bearing damage scenarios.Finally,the efficiency of the method is justified by considering its application to identifying cracking damage for a real continuous beam bridge called Xinyihe Bridge.It is concluded that the EMSE damage index is sensitive to the cracking damage and the bearing damage.The locations and levels of multiple cracking damages and bearing damages can be also identified.The results illuminate a great potential of the proposed method in identifying damages of real bridge structures.展开更多
HfO2 and SiO2 single layer is deposited on glass substrate with plasma ion assistance provided by Leybold advanced plasma source （APS）. The deposition is performed with a bias voltage in the range of 70-130 V for Hf...HfO2 and SiO2 single layer is deposited on glass substrate with plasma ion assistance provided by Leybold advanced plasma source （APS）. The deposition is performed with a bias voltage in the range of 70-130 V for HfO2, and 70-170 V for SiO2. Optical, structural, mechanical properties, as well as absorption and laser induced damage threshold at 1064 nm of HfO2 and SiO2 single layer deposited with the plasma ion assistance are systematically investigated. With the increase of APS bias voltage, coatings with higher refractive index, reduced surface roughness, and higher laser-induced damage threshold （LIDT） are obtained, and no significant change of the absorption at 1064 nm is observed. For HfO2, a bias voltage can be identified to achieve coatings without any stress. However, too-high bias voltage can cause the increase of surface roughness and stress, and decrease the LIDT. The bias voltage can be properly identified to achieve coatings with desired properties.展开更多
There are several fatigue-based approaches that estimate the evolution of rolling contact fatigue(RCF) on rails over time and built to be used in tandem with multibody simulations of vehicle dynamics. However, most of...There are several fatigue-based approaches that estimate the evolution of rolling contact fatigue(RCF) on rails over time and built to be used in tandem with multibody simulations of vehicle dynamics. However, most of the models are not directly comparable with each other since they are based on different physical models even though they shall predict the same RCF damage at the end.This article studies different approaches to quantifying RCF and puts forward a measure for the degree of agreement between them. The methodological framework studies various steps in the RCF quantification procedure within the context of one another, identifies the ‘primary quantification step’ in each approach and compares results of the fatigue analyses. In addition to this, two quantities—‘similarity’ and ‘correlation’—have been put forward to give an indication of mutual agreement between models.Four widely used surface-based and sub-surface-based fatigue quantification approaches with varying complexities have been studied. Different operational cases corresponding to a metro vehicle operation in Austria have been considered for this study. Results showed that the best possible quantity to compare is the normalized damage increment per loading cycle coming from different approaches. Amongst the methods studied, approaches that included the load distribution step on the contact patch showed higher similarity and correlation in their results.While the different approaches might qualitatively agree on whether contact cases are ‘damaging’ due to RCF, they might not quantitatively correlate with the trends observed for damage increment values.展开更多
The severity of an initial burn injury is critical for determining the treatment plan and prognosis of burn patients. Here, we measured serum neutrophil gelatinase-associated lipocalin (NGAL) levels to determine wheth...The severity of an initial burn injury is critical for determining the treatment plan and prognosis of burn patients. Here, we measured serum neutrophil gelatinase-associated lipocalin (NGAL) levels to determine whether NGAL can be used as a biomarker for severity of burn injuries. A study of the demographic, clinical, and laboratory markers for various organ damage was performed at Bestian Burn Center (n = 10 healthy people, n = 31 patients). NGAL and organ damage marker levels were measured in 31 patients with severe burns within 2 - 3 days following their admission to the intensive care unit. Serum NGAL level of the expired patients was 788.5 (685.0 - 998.0) pg/mL, whereas that of the discharged patients was 421.2 (356.2 - 480.6) pg/mL, showing that the initial serum NGAL level can be used to estimate mortality. We also determined the correlation between serum NGAL level and the currently used severity markers (total body surface area burned and abbreviated burn severity index) and confirmed that serum NGAL level could be used as a severity marker. We also found that serum NGAL level was correlated with damage of organs such as the liver, kidney, heart, and respiratory organs in patients with severe burns.展开更多
基金The National Natural Science Foundation of China(Grant Nos.51178101 and 51378112)The University Graduate Student Scientific Research Innovation Plan of Jiangsu Province(Grant No.CXZZ13_0109)China Scholarship Council under Program for Graduate Student Overseas Study Scholarship
文摘A timely and accurate damage identification for bridge structures is essential to prevent sudden failures/collapses and other catastrophic accidents.Based on response surface model(RSM)updating and element modal strain energy(EMSE)damage index,this paper proposes a novel damage identification method for girder bridge structures.The effectiveness of the proposed damage identification method is investigated using experiments on four simply supported steel beams.With Xiabaishi Bridge,a prestressed continuous rigid frame bridge with large span,as the engineering background,the proposed damage identification method is validated by using numerical simulation to generate different bearing damage scenarios.Finally,the efficiency of the method is justified by considering its application to identifying cracking damage for a real continuous beam bridge called Xinyihe Bridge.It is concluded that the EMSE damage index is sensitive to the cracking damage and the bearing damage.The locations and levels of multiple cracking damages and bearing damages can be also identified.The results illuminate a great potential of the proposed method in identifying damages of real bridge structures.
文摘HfO2 and SiO2 single layer is deposited on glass substrate with plasma ion assistance provided by Leybold advanced plasma source （APS）. The deposition is performed with a bias voltage in the range of 70-130 V for HfO2, and 70-170 V for SiO2. Optical, structural, mechanical properties, as well as absorption and laser induced damage threshold at 1064 nm of HfO2 and SiO2 single layer deposited with the plasma ion assistance are systematically investigated. With the increase of APS bias voltage, coatings with higher refractive index, reduced surface roughness, and higher laser-induced damage threshold （LIDT） are obtained, and no significant change of the absorption at 1064 nm is observed. For HfO2, a bias voltage can be identified to achieve coatings without any stress. However, too-high bias voltage can cause the increase of surface roughness and stress, and decrease the LIDT. The bias voltage can be properly identified to achieve coatings with desired properties.
基金funding from the Shift2Rail Joint Undertaking (JU) under the European Union’s Horizon 2020 research and innovation programme under grant agreement (No. 826206)。
文摘There are several fatigue-based approaches that estimate the evolution of rolling contact fatigue(RCF) on rails over time and built to be used in tandem with multibody simulations of vehicle dynamics. However, most of the models are not directly comparable with each other since they are based on different physical models even though they shall predict the same RCF damage at the end.This article studies different approaches to quantifying RCF and puts forward a measure for the degree of agreement between them. The methodological framework studies various steps in the RCF quantification procedure within the context of one another, identifies the ‘primary quantification step’ in each approach and compares results of the fatigue analyses. In addition to this, two quantities—‘similarity’ and ‘correlation’—have been put forward to give an indication of mutual agreement between models.Four widely used surface-based and sub-surface-based fatigue quantification approaches with varying complexities have been studied. Different operational cases corresponding to a metro vehicle operation in Austria have been considered for this study. Results showed that the best possible quantity to compare is the normalized damage increment per loading cycle coming from different approaches. Amongst the methods studied, approaches that included the load distribution step on the contact patch showed higher similarity and correlation in their results.While the different approaches might qualitatively agree on whether contact cases are ‘damaging’ due to RCF, they might not quantitatively correlate with the trends observed for damage increment values.
文摘The severity of an initial burn injury is critical for determining the treatment plan and prognosis of burn patients. Here, we measured serum neutrophil gelatinase-associated lipocalin (NGAL) levels to determine whether NGAL can be used as a biomarker for severity of burn injuries. A study of the demographic, clinical, and laboratory markers for various organ damage was performed at Bestian Burn Center (n = 10 healthy people, n = 31 patients). NGAL and organ damage marker levels were measured in 31 patients with severe burns within 2 - 3 days following their admission to the intensive care unit. Serum NGAL level of the expired patients was 788.5 (685.0 - 998.0) pg/mL, whereas that of the discharged patients was 421.2 (356.2 - 480.6) pg/mL, showing that the initial serum NGAL level can be used to estimate mortality. We also determined the correlation between serum NGAL level and the currently used severity markers (total body surface area burned and abbreviated burn severity index) and confirmed that serum NGAL level could be used as a severity marker. We also found that serum NGAL level was correlated with damage of organs such as the liver, kidney, heart, and respiratory organs in patients with severe burns.
