Vibration Characteristics of Laminated Composite Folded Plates

Abstract In this paper, the vibration characteristics of laminated composite cantilever beam is taken as the research object. Firstly, a vibration formula specific for laminated composite cantilever beam is derived, from which the low order natural frequency of laminated composite cantilever beam is calculated; Secondly, two experimental methods, electrical and optical measurement, are used to study the vibration characteristics of laminated composite cantilever beam, and the influence of different test methods, sensor types, number of measuring points and excitation methods on the test results are analyzed. Through the combination of theory and experiment, a test method that can be applied to the vibration test of composite material laminated structure cantilever beam is obtained. Based on the laser vibration measurement method in the optical method, the results show that the deviation between the experimental data and the theoretical solution is the smallest when the distance between the probe and the specimen is 0.5m and the sampling time is 5s by using the optical fiber vibrometer. The research content of this article can provide a reasonable reference for related vibration test research.

Download Full-text

FiniteElement Vibration Characteristics of Composite Hypar Shallow Shells with Various Edge Supports

Journal of Vibration and Control ◽

10.1177/1077546305057260 ◽

2005 ◽

Vol 11 (10) ◽

pp. 1291-1309 ◽

Cited By ~ 21

Author(s):

S. Sahoo ◽

D. Chakravorty

Keyword(s):

Boundary Conditions ◽

Numerical Experiments ◽

Laminated Composite ◽

Shell Element ◽

Vibration Characteristics ◽

The Other ◽

Mode Shapes ◽

Review Of The Literature ◽

Shallow Shells ◽

Fundamental Frequencies

A review of the literature reveals that information regarding fundamental frequencies and mode shapes of shallow laminated composite hypar shells with practical civil engineering boundary conditions is not available. The present investigation aims to fill this gap by applying an eight-noded isoparametric shell element as the tool. Numerical experiments are carried out for different parametric variations including boundary conditions and stacking orders to obtain the fundamental frequencies and mode shapes. Some of the results are used for validating the correctness of the present approach by comparing with the existing benchmark, while the other results are studied meticulously to extract a set of meaningful conclusions regarding the free vibration characteristics of composite shallow hypar shells.

Download Full-text

A Study on Vibration Characteristics of Laminated Composite Cylindrical Shells. An Influence of Material Anisotropy and Geometric Parameters of Shells on Natural Frequencies.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C ◽

10.1299/kikaic.64.1479 ◽

1998 ◽

Vol 64 (621) ◽

pp. 1479-1484

Author(s):

Tetsuya NARISAWA ◽

Masanori KAWAHARA ◽

Kohei SUZUKI

Keyword(s):

Natural Frequencies ◽

Cylindrical Shells ◽

Laminated Composite ◽

Vibration Characteristics ◽

Geometric Parameters ◽

Material Anisotropy ◽

Composite Cylindrical Shells

Download Full-text

Damage Detection in Laminated Composite Plates and Shells Using Second Derivatives of Mode Shape Data Through Dynamic Analysis of These Structures

Volume 4B: Dynamics, Vibration, and Control ◽

10.1115/imece2015-51600 ◽

2015 ◽

Author(s):

Mahendran Govindasamy ◽

Chandrasekaran Kesavan ◽

Malhotra Santkumar

Keyword(s):

Damage Detection ◽

Mode Shape ◽

Laminated Composite ◽

Vibration Characteristics ◽

Mode Shapes ◽

Experimental Investigations ◽

Structural Elements ◽

Plate And Shell ◽

Second Derivatives ◽

Derivatives Of

The main objective of this study is to evaluate the dynamics-based techniques for damage detection in laminated composite cantilevered rectangular plates and cylindrical shells with damages in the form of surface macro-level cracks using finite element analysis (FEA). However, the quantitative change in global vibration characteristics is not sufficiently sensitive to local structural damages especially to small size damages. Hence certain parameters called damage indicators based on mode shape curvature, which are the second derivatives of the vibration characteristics (mode shapes), are used in this study to detect the location and size of even small damages accurately in laminated composite structures. The commercial FEA package ANSYS is used for the theoretical modal analysis to generate the natural frequencies and normalized mode shapes of the intact and damaged structures. Experimental investigations are carried out on the laminated plate and shell structural elements to provide a validation of the analysis. Experimental investigations are carried out on the laminated composite (E-glass unidirectional fibers reinforced epoxy resin) cantilevered plate and shell structural elements to provide a validation of the analysis. The effectiveness of these methods is clearly demonstrated by the results obtained.

Download Full-text