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Cable modal parameter identification. I / Wei-Xin Ren in Journal of engineering mechanics, Vol. 135 N°1 (Janvier 2009) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 135 N°1 (Janvier 2009) . - pp. 41-50 Titre : Cable modal parameter identification. I : theory Type de document : texte imprimé Auteurs : Wei-Xin Ren, Auteur ; Wei-Hua Hu, Auteur Année de publication : 2009 Article en page(s) : pp. 41-50 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Construction  equipment  Cables  Stiffness  Vibration  Parameters  Least  squares  method  Theories. Résumé : Cable modal parameters (natural frequencies and damping ratios) that represent the cable inherent dynamic characteristics play an important role in the construction, vibration control, condition assessment, and long-term health monitoring of cable-supported structures. The existing options to identify cable modal parameters through vibration measurements are somewhat limited. For this purpose, a cable dynamic stiffness based method is presented to effectively identify the cable modal parameters. In the first part of this two-part paper, the cable dynamic stiffness is analytically discussed for a viscously damped, uniform, inclined sagging cable supported at the lower end and subjected to a harmonically varying arbitrary angle displacement excitation in an arbitrary angle at the upper end when the cable is assumed to have a parabolic profile at its position of static equilibrium. Special attention is paid to the physical meaning and significance of every part of the frequency-dependent closed-form cable dynamic stiffness. Comprehensive numerical analyses have been carried out and a simplified cable dynamic stiffness is proposed for the purpose of identifying the cable modal parameters with a good accuracy over a wide range of frequencies. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...] [article] Cable modal parameter identification. I : theory [texte imprimé] / Wei-Xin Ren, Auteur ; Wei-Hua Hu, Auteur . - 2009 . - pp. 41-50. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 135 N°1 (Janvier 2009) . - pp. 41-50 Mots-clés : Construction  equipment  Cables  Stiffness  Vibration  Parameters  Least  squares  method  Theories. Résumé : Cable modal parameters (natural frequencies and damping ratios) that represent the cable inherent dynamic characteristics play an important role in the construction, vibration control, condition assessment, and long-term health monitoring of cable-supported structures. The existing options to identify cable modal parameters through vibration measurements are somewhat limited. For this purpose, a cable dynamic stiffness based method is presented to effectively identify the cable modal parameters. In the first part of this two-part paper, the cable dynamic stiffness is analytically discussed for a viscously damped, uniform, inclined sagging cable supported at the lower end and subjected to a harmonically varying arbitrary angle displacement excitation in an arbitrary angle at the upper end when the cable is assumed to have a parabolic profile at its position of static equilibrium. Special attention is paid to the physical meaning and significance of every part of the frequency-dependent closed-form cable dynamic stiffness. Comprehensive numerical analyses have been carried out and a simplified cable dynamic stiffness is proposed for the purpose of identifying the cable modal parameters with a good accuracy over a wide range of frequencies. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...]

Cable modal parameter identification. II / Wei-Xin Ren in Journal of engineering mechanics, Vol. 135 N°1 (Janvier 2009) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 135 N°1 (Janvier 2009) . - pp. 51-61 Titre : Cable modal parameter identification. II : modal tests Type de document : texte imprimé Auteurs : Wei-Xin Ren, Auteur ; Wei-Hua Hu, Auteur Année de publication : 2009 Article en page(s) : pp. 51-61 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Cables  Stiffness  Vibration  Parameters  Least  squares  method. Résumé : The cable dynamic stiffness describes the load–deformation behavior that reflects the cable intrinsic dynamic characteristics. It is defined as a ratio of response to excitation and represents a very similar frequency response property to the frequency response function (FRF). Therefore, by fitting both analytical cable dynamic stiffness and measured frequency response function, the modal parameters of cables can be identified. Based on the simplified cable dynamic stiffness proposed in the first part of the two-part paper, this paper presents a cable dynamic stiffness based procedure to identify the cable modal parameters (natural frequencies and damping ratios) by modal tests. To carry out the curve fitting, a nonlinear least-squares approach is used. A numerical simulation example is first introduced to illustrate the feasibility of the proposed method. Further, a series of cable modal tests are conducted in the laboratory with different cable tensions and the frequency response functions are measured accordingly. A number of issues related to the cable modal tests have been discussed, such as accelerometer arrangement and excitation placement, frequency resolution, windowing, and averaging. It is demonstrated that the cable modal parameters can be effectively identified by using the proposed method through the cable modal tests. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...] [article] Cable modal parameter identification. II : modal tests [texte imprimé] / Wei-Xin Ren, Auteur ; Wei-Hua Hu, Auteur . - 2009 . - pp. 51-61. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 135 N°1 (Janvier 2009) . - pp. 51-61 Mots-clés : Cables  Stiffness  Vibration  Parameters  Least  squares  method. Résumé : The cable dynamic stiffness describes the load–deformation behavior that reflects the cable intrinsic dynamic characteristics. It is defined as a ratio of response to excitation and represents a very similar frequency response property to the frequency response function (FRF). Therefore, by fitting both analytical cable dynamic stiffness and measured frequency response function, the modal parameters of cables can be identified. Based on the simplified cable dynamic stiffness proposed in the first part of the two-part paper, this paper presents a cable dynamic stiffness based procedure to identify the cable modal parameters (natural frequencies and damping ratios) by modal tests. To carry out the curve fitting, a nonlinear least-squares approach is used. A numerical simulation example is first introduced to illustrate the feasibility of the proposed method. Further, a series of cable modal tests are conducted in the laboratory with different cable tensions and the frequency response functions are measured accordingly. A number of issues related to the cable modal tests have been discussed, such as accelerometer arrangement and excitation placement, frequency resolution, windowing, and averaging. It is demonstrated that the cable modal parameters can be effectively identified by using the proposed method through the cable modal tests. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JENMDT000 [...]