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A platform for research: civil engineering, architecture and urbanism
Investigation of Global and Local Free Vibration of Slender FRP Beams
https://orcid.org/0000-0003-2371-9272
https://orcid.org/0000-0002-8171-7956
This paper addresses a theoretical investigation of the undamped free vibration of slender fiber-reinforced polymer (FRP) beams. While previous studies have focused on global vibration modes in the range of excitation frequencies reported in typical civil engineering problems, the present one discusses the influence of local modes, which can be useful for nondestructive indirect characterizations of materials and detection of damage in bridges and frames. Appropriate shape functions for flexural, flexural–torsional, torsional, and local vibration modes were chosen, and Lagrange’s equations of motion were derived after determination of the energy components. The formulation accounts for C and I sections, different end conditions, and enriched shapes for local modes, and transverse shear deformation is neglected. The results from the proposed equations for a C section were compared to those from generalized beam theory (GBT). Overall, an excellent agreement with GBT was achieved, except for global modes in beams of relatively short equivalent length, in which transverse shear deformation is relevant. Regarding local modes, the associated natural frequency tends to stabilize with increasing lengths and the transverse stiffness component plays a major role in the modal behavior. A study of the influences of flange width and cross-sectional shape (C and I) revealed that frequency drops significantly when flanges become wider. The influence of transverse shear was negligible for beams with a higher than 40 slenderness ratio. The formulation was successfully compared to a previous experiment performed by the authors.
Investigation of Global and Local Free Vibration of Slender FRP Beams
https://orcid.org/0000-0003-2371-9272
https://orcid.org/0000-0002-8171-7956
This paper addresses a theoretical investigation of the undamped free vibration of slender fiber-reinforced polymer (FRP) beams. While previous studies have focused on global vibration modes in the range of excitation frequencies reported in typical civil engineering problems, the present one discusses the influence of local modes, which can be useful for nondestructive indirect characterizations of materials and detection of damage in bridges and frames. Appropriate shape functions for flexural, flexural–torsional, torsional, and local vibration modes were chosen, and Lagrange’s equations of motion were derived after determination of the energy components. The formulation accounts for C and I sections, different end conditions, and enriched shapes for local modes, and transverse shear deformation is neglected. The results from the proposed equations for a C section were compared to those from generalized beam theory (GBT). Overall, an excellent agreement with GBT was achieved, except for global modes in beams of relatively short equivalent length, in which transverse shear deformation is relevant. Regarding local modes, the associated natural frequency tends to stabilize with increasing lengths and the transverse stiffness component plays a major role in the modal behavior. A study of the influences of flange width and cross-sectional shape (C and I) revealed that frequency drops significantly when flanges become wider. The influence of transverse shear was negligible for beams with a higher than 40 slenderness ratio. The formulation was successfully compared to a previous experiment performed by the authors.
Investigation of Global and Local Free Vibration of Slender FRP Beams
https://orcid.org/0000-0003-2371-9272
https://orcid.org/0000-0002-8171-7956
This paper addresses a theoretical investigation of the undamped free vibration of slender fiber-reinforced polymer (FRP) beams. While previous studies have focused on global vibration modes in the range of excitation frequencies reported in typical civil engineering problems, the present one discusses the influence of local modes, which can be useful for nondestructive indirect characterizations of materials and detection of damage in bridges and frames. Appropriate shape functions for flexural, flexural–torsional, torsional, and local vibration modes were chosen, and Lagrange’s equations of motion were derived after determination of the energy components. The formulation accounts for C and I sections, different end conditions, and enriched shapes for local modes, and transverse shear deformation is neglected. The results from the proposed equations for a C section were compared to those from generalized beam theory (GBT). Overall, an excellent agreement with GBT was achieved, except for global modes in beams of relatively short equivalent length, in which transverse shear deformation is relevant. Regarding local modes, the associated natural frequency tends to stabilize with increasing lengths and the transverse stiffness component plays a major role in the modal behavior. A study of the influences of flange width and cross-sectional shape (C and I) revealed that frequency drops significantly when flanges become wider. The influence of transverse shear was negligible for beams with a higher than 40 slenderness ratio. The formulation was successfully compared to a previous experiment performed by the authors.
Investigation of Global and Local Free Vibration of Slender FRP Beams
J. Compos. Constr.
Gaspar, Cássio Marques Rodrigues (author) / Cardoso, Daniel Carlos Taissum (author)
2023-06-01
Article (Journal)
Electronic Resource
English
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