Identification of Loss Factor of Fiber-Reinforced Composite Based on Complex Modulus Method

Hui Li,Chao Mu,Yi Niu,Bangchun Wen

doi:10.1155/2017/6395739

Abstract

The identification of the loss factor of fiber-reinforced composite based on complex modulus method is presented. Firstly, the damping model of fiber-reinforced composite plate is established, and the relation between each loss factor and modal damping ratio is deduced based on the complex modulus method. Then, the least square relative error function is formed by using the modal damping ratio obtained in the experimental test, and the appropriate step-size is selected in the range of 0~10% to calculate the loss factor. Next, the identification procedure of loss factor of such composite material is summarized, and the corresponding identification procedure is realized based on self-designed MATLAB program. Finally, TC300 carbon/epoxy composite plate is taken as an example to carry out a case study, and its loss factors along the longitudinal, transverse, and shear direction are identified by the complex modulus method. By comparing the measured damping results obtained in this paper and the calculated damping results based on the Adams-Bacon model with the same loss factor, it is found that the corresponding maximum deviation between them is less than 15%, so the correctness of such identification method has been verified indirectly, which can be used to identify loss factor of fiber-reinforced composite with high precision and efficiency.

Highlights

Fiber-reinforced composite has excellent mechanical properties, good thermal stability, and capability for weight reduction, which is widely used in the area of aeronautics, astronautics, automotive, naval vessel, and weapon industry [1, 2]
They considered that the energy consumed by each thin layer in the composite plate was the sum of its longitudinal tensile, transverse tensile, and shear stresses
By comparing the measured damping results obtained in this paper and the calculated damping results based on the Adams-Bacon model with the same loss factor, the correctness of such identification method has been verified indirectly

Summary

Introduction

Fiber-reinforced composite has excellent mechanical properties, good thermal stability, and capability for weight reduction, which is widely used in the area of aeronautics, astronautics, automotive, naval vessel, and weapon industry [1, 2]. De Visscher et al [10] proposed a mixed numerical-experimental method for the identification of the material damping properties of fiber-reinforced polymer composites, and the complex elastic moduli were introduced, so that the modal strain energy can be expressed as the sum of four partial energies which were longitudinal tensile, transverse tensile, shear stresses, and thickness direction. Matter et al [19] presented a mixed numerical-experimental identification method for estimating the loss factor of composite plates and shells, and the natural frequencies, modal damping factors, and mode shapes of the specimen were measured with an optimized contact-free experimental setup, which used a loudspeaker for exciting the structure and a scanning laser interferometer for measuring the dynamic response. Devalve and Pitchumani [20] investigated the damping effects of carbon nanotubes embedded in the matrix of fiber-reinforced composite material, and dynamic mechanical analysis (DMA) system was employed in the dual-cantilever mode of the composite beam to measure its material loss factor

Methods

Results

Discussion

Conclusion