The practical difficulties presented by forced vibration testing of large steel structures, such as tall buildings, transmission lines or bridges, led to an increased interest in structural monitoring through ambient ...The practical difficulties presented by forced vibration testing of large steel structures, such as tall buildings, transmission lines or bridges, led to an increased interest in structural monitoring through ambient vibrations, which usually allows the proper identification of modal properties, natural frequencies, damping and modes of vibration. Changes in these modal properties constitute an indication of structural damage, which may then be assessed on the basis of experimental evidence. The authors proposed an approach to determine the so-called damage damping and stiffness matrices, which are essential to identify the location and intensity of damage. No restrictions were introduced on the damping matrix of the system. The approach requires ambient vibration data of all relevant coordinates used in the structural model, which are processed employing the SSI method. In practice, the identification method is seriously hampered by ambient factors such as temperature or humidity. In general those effects must be filtered out in other to obtain a reliable diagnosis of damage, approach that demands long term monitoring. In this paper, an alternative approach is explored, based on the introduction of error damping and stiffness matrices. Data on both matrices is generated on the basis of observed variations of structural member stiffness and damping caused by ambient factors. The influence of this uncertainty on the identified spectral properties is assessed by simulation.展开更多
Beethoven is a famous German pianist, composer, and conductor, and he set the culmination of Western classical, created a romantic music camp precedent. The size of his music in general is very ambitious, mostly conce...Beethoven is a famous German pianist, composer, and conductor, and he set the culmination of Western classical, created a romantic music camp precedent. The size of his music in general is very ambitious, mostly concertos, symphonies, operas and other large works, technical approach and structure used is quite complex, people are left with a deep impression. But it works, while small piano pieces, also has music research value, ＂dedicated to Alice＂ is one of the few Beethoven piano pieces. This paper focuses on creative background ＂dedicated to Alice,＂ this elaborate piano works by the complexity of the analysis of the structure of this work is that it reflects the author＇ s ideological soul to explore their musical value.展开更多
文摘The practical difficulties presented by forced vibration testing of large steel structures, such as tall buildings, transmission lines or bridges, led to an increased interest in structural monitoring through ambient vibrations, which usually allows the proper identification of modal properties, natural frequencies, damping and modes of vibration. Changes in these modal properties constitute an indication of structural damage, which may then be assessed on the basis of experimental evidence. The authors proposed an approach to determine the so-called damage damping and stiffness matrices, which are essential to identify the location and intensity of damage. No restrictions were introduced on the damping matrix of the system. The approach requires ambient vibration data of all relevant coordinates used in the structural model, which are processed employing the SSI method. In practice, the identification method is seriously hampered by ambient factors such as temperature or humidity. In general those effects must be filtered out in other to obtain a reliable diagnosis of damage, approach that demands long term monitoring. In this paper, an alternative approach is explored, based on the introduction of error damping and stiffness matrices. Data on both matrices is generated on the basis of observed variations of structural member stiffness and damping caused by ambient factors. The influence of this uncertainty on the identified spectral properties is assessed by simulation.
文摘Beethoven is a famous German pianist, composer, and conductor, and he set the culmination of Western classical, created a romantic music camp precedent. The size of his music in general is very ambitious, mostly concertos, symphonies, operas and other large works, technical approach and structure used is quite complex, people are left with a deep impression. But it works, while small piano pieces, also has music research value, ＂dedicated to Alice＂ is one of the few Beethoven piano pieces. This paper focuses on creative background ＂dedicated to Alice,＂ this elaborate piano works by the complexity of the analysis of the structure of this work is that it reflects the author＇ s ideological soul to explore their musical value.
