风险评估技术对保障长输管道的安全运行具有重要作用,场站管道由于结构的复杂及与设备联系密切,对它进行风险评估尤为关键。通过对所研究的场站管道评估数据的分析,依据国内的相关标准和国外DNV软件,研究开发了针对场站管道的RBI(Risk B...风险评估技术对保障长输管道的安全运行具有重要作用,场站管道由于结构的复杂及与设备联系密切,对它进行风险评估尤为关键。通过对所研究的场站管道评估数据的分析,依据国内的相关标准和国外DNV软件,研究开发了针对场站管道的RBI(Risk Based Inspection)评估系统。主要研究内容包括:研究确定了场站管道RBI评估方法;建立场站管道基于检测的风险评估模型,采用Labview和Matlab软件开发了场站管道的RBI评估系统软件;利用此软件可进行场站管道的失效可能性和失效后果两方面的分析,并综合得到场站管道的风险评估结论,由此可有针对性地提出提高场站管道安全可靠性的措施。通过对白沙湾输油站管道的风险评估实例验证了所开发的系统的可行性和正确性。展开更多
Results of the Ocean General Circulation Model for the Earth Simulator（OFES） from January 1977 to December2006 are used to investigate mesoscale eddies near the Ryukyu Islands. The results show that：（1） Larger ed...Results of the Ocean General Circulation Model for the Earth Simulator（OFES） from January 1977 to December2006 are used to investigate mesoscale eddies near the Ryukyu Islands. The results show that：（1） Larger eddies are mainly east of Taiwan, above the Ryukyu Trench and south of the Shikoku Island. These three sea areas are all in the vicinity of the Ryukyu Current.（2） Eddies in the area of the Ryukyu Current are mainly anticyclonic, and conducive to that current. The transport of water east of the Ryukyu Islands is mainly toward the northeast.（3）The Ryukyu Current is significantly affected by the eddies. The lower the latitude, the greater these effects.However, the Kuroshio is relatively stable, and the effect of mesoscale eddies is not significant.（4） A warm eddy south of the Shikoku Island break away from the Kuroshio and move southwest, and is clearly affected by the Ryukyu Current and Kuroshio. Relationships between the mesoscale eddies, Kuroshio meanders, and Ryukyu Current are discussed.展开更多
Changes(degradations) in the mechanical properties of solid plates induced by cyclic fatigue loading will influence the features of ultrasonic Lamb wave propagation,such as dispersion and attenuation.This paper has qu...Changes(degradations) in the mechanical properties of solid plates induced by cyclic fatigue loading will influence the features of ultrasonic Lamb wave propagation,such as dispersion and attenuation.This paper has qualitatively analyzed the feasibility of using the amplitude-frequency characteristics and the stress wave factors(SWFs) of ultrasonic Lamb wave propagation to assess fatigue damage in solid plates.Liquid wedge transducers located on the surface of solid plates tested are used to generate and detect the Lamb wave signals.Based on the Ritec-SNAP ultrasonic measurement system,the experimental setup for assessing the degree of fatigue damage in solid plates using ultrasonic Lamb wave approach has been established.For several rolled aluminum sheets subjected to tension-tension cyclic loading,the experimental examinations have been performed for the relationships between the amplitude-frequency characteristics of ultrasonic Lamb wave propagation and the numbers of loading cycles(denoted by N),as well as the correlations between the Lamb wave SWFs and N.The experimental results show that the Lamb wave SWFs decrease monotonously and sensitively with the increment of cycles of fatigue loading.Based on the correlations between the Lamb wave SWFs and N,it is further verified that ultrasonic Lamb wave propagation combined with the Lamb wave SWFs can be used to effectively assess early fatigue damage in solid plates.展开更多
This paper studies the mode selection of Lamb waves for evaluating solid plates with liquid loading. For this purpose, the Lamb wave selected should have the features such as zero normal displacement components at the...This paper studies the mode selection of Lamb waves for evaluating solid plates with liquid loading. For this purpose, the Lamb wave selected should have the features such as zero normal displacement components at the plate surface in contact with liquid, small dispersion, and maximum group velocity. It is found that when the phase velocity of Lamb wave is equal to the longitudinal wave velocity of the plate material, its normal displacement at the plate surface is always zero. Through the numerical analyses, the specific S2 Lamb wave that has zero normal displacement component at the plate surface, small dispersion and maximum group velocity compared with the other Lamb waves has been found. With respect to the specific S2 Lamb wave, some experimental examinations have been carried out. It is found that the liquid loading on the plate surface has less influence on the specific S2 Lamb wave signal but it can effectively eliminate the other signals. Moreover, the specific S2 Lamb wave selected exhibits the capability of detecting multiple defects in the solid plate with the liquid loading. It can be concluded that the specific S2 Lamb wave selected is suitable for the evaluation of solid plates with liquid loading.展开更多
文摘风险评估技术对保障长输管道的安全运行具有重要作用,场站管道由于结构的复杂及与设备联系密切,对它进行风险评估尤为关键。通过对所研究的场站管道评估数据的分析,依据国内的相关标准和国外DNV软件,研究开发了针对场站管道的RBI(Risk Based Inspection)评估系统。主要研究内容包括:研究确定了场站管道RBI评估方法;建立场站管道基于检测的风险评估模型,采用Labview和Matlab软件开发了场站管道的RBI评估系统软件;利用此软件可进行场站管道的失效可能性和失效后果两方面的分析,并综合得到场站管道的风险评估结论,由此可有针对性地提出提高场站管道安全可靠性的措施。通过对白沙湾输油站管道的风险评估实例验证了所开发的系统的可行性和正确性。
基金The National Natural Science Foundation of China under contract No.41076003the Youth Science and Technology Foundation of East China Sea Branch,SOA under contract Nos 201314 and 201203the open fund of State Key Laboratory of Satellite Ocean Environment Dynamics under Contract No.SOED1402
文摘Results of the Ocean General Circulation Model for the Earth Simulator（OFES） from January 1977 to December2006 are used to investigate mesoscale eddies near the Ryukyu Islands. The results show that：（1） Larger eddies are mainly east of Taiwan, above the Ryukyu Trench and south of the Shikoku Island. These three sea areas are all in the vicinity of the Ryukyu Current.（2） Eddies in the area of the Ryukyu Current are mainly anticyclonic, and conducive to that current. The transport of water east of the Ryukyu Islands is mainly toward the northeast.（3）The Ryukyu Current is significantly affected by the eddies. The lower the latitude, the greater these effects.However, the Kuroshio is relatively stable, and the effect of mesoscale eddies is not significant.（4） A warm eddy south of the Shikoku Island break away from the Kuroshio and move southwest, and is clearly affected by the Ryukyu Current and Kuroshio. Relationships between the mesoscale eddies, Kuroshio meanders, and Ryukyu Current are discussed.
基金supported by the National Natural Science Foundation of China (Grant No. 10674180)the National Science Foundation Project of Chongqing Science and Technology Commission (Grant No. 2008BB0140)
文摘Changes(degradations) in the mechanical properties of solid plates induced by cyclic fatigue loading will influence the features of ultrasonic Lamb wave propagation,such as dispersion and attenuation.This paper has qualitatively analyzed the feasibility of using the amplitude-frequency characteristics and the stress wave factors(SWFs) of ultrasonic Lamb wave propagation to assess fatigue damage in solid plates.Liquid wedge transducers located on the surface of solid plates tested are used to generate and detect the Lamb wave signals.Based on the Ritec-SNAP ultrasonic measurement system,the experimental setup for assessing the degree of fatigue damage in solid plates using ultrasonic Lamb wave approach has been established.For several rolled aluminum sheets subjected to tension-tension cyclic loading,the experimental examinations have been performed for the relationships between the amplitude-frequency characteristics of ultrasonic Lamb wave propagation and the numbers of loading cycles(denoted by N),as well as the correlations between the Lamb wave SWFs and N.The experimental results show that the Lamb wave SWFs decrease monotonously and sensitively with the increment of cycles of fatigue loading.Based on the correlations between the Lamb wave SWFs and N,it is further verified that ultrasonic Lamb wave propagation combined with the Lamb wave SWFs can be used to effectively assess early fatigue damage in solid plates.
基金supported by the National Natural Science Foundation of China(Grant No.11274388)
文摘This paper studies the mode selection of Lamb waves for evaluating solid plates with liquid loading. For this purpose, the Lamb wave selected should have the features such as zero normal displacement components at the plate surface in contact with liquid, small dispersion, and maximum group velocity. It is found that when the phase velocity of Lamb wave is equal to the longitudinal wave velocity of the plate material, its normal displacement at the plate surface is always zero. Through the numerical analyses, the specific S2 Lamb wave that has zero normal displacement component at the plate surface, small dispersion and maximum group velocity compared with the other Lamb waves has been found. With respect to the specific S2 Lamb wave, some experimental examinations have been carried out. It is found that the liquid loading on the plate surface has less influence on the specific S2 Lamb wave signal but it can effectively eliminate the other signals. Moreover, the specific S2 Lamb wave selected exhibits the capability of detecting multiple defects in the solid plate with the liquid loading. It can be concluded that the specific S2 Lamb wave selected is suitable for the evaluation of solid plates with liquid loading.
