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Copyright of Journal of Southeast University / Dongnan Daxue Xuebao is the property of Journal of Southeast University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The vibration isolation and absorption technologies for ship mechanical systems were reviewed, such as the concept, the application background, and the research status of floating raft vibration isolation systems and dynamic vibration absorbers. Meanwhile, the concept and development of passive control and active control were also analyzed. The smart materials and new structural forms were summarized. The concept, the working condition and the development of control components such as the quasi-zero stiffness vibration isolator, the acoustic black hole structure, the intelligent material actuator, and the active and semi-active dynamic vibration absorbers, were considered, and the control strategies of the active control were discussed. Besides, the theoretical and numerical methods for modelling, calculating and testing mechanical damping systems were also surveyed. At last, the development trend of the ship mechanical vibration reduction and isolation system was envisioned and portrayed. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A hammering test is an experimental modal analysis method widely used in academia and industry. The spectral estimation method is usually used to calculate the frequency response function (FRF), which is extremely susceptible to length and quality of the measurement data. In recent years, the Bayesian learning technology has provided a new exploration approach for the system and the control field. Inspired by this, the prior information of the FRF is statistically described by a complex Gaussian process, and a Bayesian inference method is developed for estimating the FRF under impact loads. The maximum posteriori estimation of the FRF is obtained, and the variance of the FRF estimation is also given. Furthermore, the numerical positive definiteness for optimizing the hyper-parameters is improved by applying QR decomposition. Finally, the effectiveness and reliability of the proposed method are verified by numerical examples and vibration experiments. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Computational Mechanics / Jisuan Lixue Xuebao is the property of Chinese Journal of Computational Mechanics Editorial Office, Dalian University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Computational Mechanics / Jisuan Lixue Xuebao is the property of Chinese Journal of Computational Mechanics Editorial Office, Dalian University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Vibration Engineering is the property of Nanjing University of Aeronautics & Astronautics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Vibration Engineering is the property of Nanjing University of Aeronautics & Astronautics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Vibration Engineering is the property of Nanjing University of Aeronautics & Astronautics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The accumulation of damage in a structure during an earthquake leads to changes in frequency response function (FRF) of the structure, and it can be used as the basis for evaluating the seismic damage condition of this structure. The finite element software ABAQUS was adopted to simulate a series of pseudo-dynamic test for a one-bay, two-story plane recycled aggregate concrete (RAC) frame. It is found that the analytical results agree well with the experimental results. Analysis of the FRFs of the RAC fame indicates that the natural frequencies for the 1st and 2nd mode are around 2.5 Hz and 6.0 Hz, respectively. The natural frequency of the tested frame decreases continuously as peak ground acceleration (PGA) increases, which indicates the accumulated damages in the frame lead to a decrease of stiffness. A damage index based on FRF was proposed for assessing the damage condition of the frame. Analytical results indicate that the damage index performs well in evaluating damage conditions for the frame subjected to different PGAs. [ABSTRACT FROM AUTHOR]

The solution of dynamic characteristics for endmills is a part of obtaining dynamic characteristics of the whole machinery by using substructure method. In order to rapidly predict the frequency response function (FRF), endmills are divided into two parts, tool shank and fluted portion. Three equivalent models based on the principle of equal mass, equal area of cross-section and equal stiffness are proposed as a uniform beam for the fluted portion, and the receptances can be easily obtained by using Timoshenko beam element for both tool shank and fluted portion. Endmill's FRF is shaped by coupling the FRF of individual part. The variation of relative errors from the three equivalent models is analyzed on these four factors: area moment of inertia of the cross-section, helix angle, percent of fluted portion lengh to tool length and ratio of tool length to diameter. The results also explain the fact that the equal stiffness method can achieve the best prediction accuracy for endmill A, B, C while the equal mass method is best for endmill D. Compared with three-dimensional harmonic analysis, the equivalent model method of endmills is computationally cheap while has an acceptable accuracy. [ABSTRACT FROM AUTHOR]

The frequency response functions (FRFs) are frequently used to identify dynamic properties of the mechanical joints. However, the ill-conditioning problems of the system are caused by the contamination of measurement noise even if it is processed by reduction technique. In order to solve this problem and make the identified results represent real properties of the joints, an improved FRFs method was developed based on condition number, in which the measured data were processed before parameter identification. The average values of the condition numbers could be found to ensure that condition number is small enough. Moreover, the frequencies corresponding to those condition numbers which are larger than average one are picked out, and comparing those retained ones the intersection frequencies are found under which the parameters are identified , thus the ill - conditioning problem can be avoided. The results of simulation and experiment show that the proposed method can solve the ill-conditioning problems, thus significantly improve the accuracy of identification. [ABSTRACT FROM AUTHOR]

Joint often have a significant effect on the dynamical behavior of assembled mechanical structures. The dynamical characteristic of joint is complex, and many researches focus on the identification of it. A new method to identify the joint pa- rameters is proposed based on the incomplete input information in this paper. Firstly, the unmeasured frequency response functions (FRFs) are identified by experimental and finite element method, and completely FRFs are constructed. Then, the dynamic parameters of joint are identified by iterative algorithms based on the completely FRFs. The loss function is estab- lished in this paper, which can be identified the parameters of joint by minimizing the loss function. Since this method does not need modal parameters, it can be used effectively to identify joint characteristics when the system has heavy damping or closely coupled modes. Furthermore, the proposed method makes use of only a few FRFs which are not necessarily related to the joint but related to easily accessible points. Thus, this method can be applied to real structures usually having rotational and inaccessible degree of freedoms. Finally, the validity and feasibility of the proposed method are demonatrated an example. The results show that joint structural parameters can be identified accurately. [ABSTRACT FROM AUTHOR]

A method for truss damage detection is proposed based on measured frequency response function (FRF) and principal component analysis (PCA). Damage detection matrix is formed using FRF obtained from truss dynamic test, and its variable space dimensions can be reduced using PCA method, thus truss damages can be detected using multi-variable control chart of first several principal components which contain the most information of all original data. In the process modal parameters are unnecessary, so the mistakes of damage detection, which arise from the errors of modal fitting in the modal analysis, can be avoided. In order to validate reliability of the proposed method, a whole size truss was tested under different damage cases. The experimental results show that the proposed method is straightforward and reliable to detect truss damages. Especially, the method has a good applicability for the truss under the noise environment and non-linear cases. [ABSTRACT FROM AUTHOR]

In order to determine the model matching index of switching control, a multiple models switching control algorithm based on effective model matching was presented. Considering that frequency response function can entirely present the essential character of underlying system, when the operating condition is varied, the change in frequency response can be utilized to realize the effective model matching and proper switching for multi-model system, which provides a novel strategy to solve switching control problem. The algorithm can effectively recognize the normal change of operating condition, and avoid the abnormal switching of models because it is not affected by disturbance. It is further demonstrated with a simulation example that the algorithm is effective on accurately recognizing the normal change of system, proper switching and following the operating condition of system. [ABSTRACT FROM AUTHOR]