Identification of material properties of orthotropic composite plate using hybrid non-destructive evaluation approach

Abstract

Identification of material properties is one of the key issues in composite materials research. This information is the most important database for an accurate Computer-Aided Engineering (CAE) simulation and various design enhancement purposes. For example, it can be used to estimate deflections and stress state of composite structure under static or dynamic load. The mechanical properties of composite materials depend on diverse factors such as configuration of the laminates, constituent materials used, production method adopted, etc. Hence, it is generally impossible to find these properties in standard tables. Conventional testing approach tends to be time-consuming, expensive and destructive. Moreover for properties such as shear modulus, these tests often yield poor results. As an alternative, a hybrid approach which utilises experimental and numerical techniques is proposed. This approach is a rapid, inexpensive and non-destructive evaluation of the mechanical properties of composite materials which involves both Experimental Modal Analysis (EMA) IntroductionComposite materials are composed of two or more different materials at macro-scale with each of the materials will contribute to the final properties. When the materials are combined, composites are generally more superior as compared to the individual components. Composite structures are usually constructed in multiple laminates where each layer is oriented specifically to achieve optimal strength and stiffness performance. Composites are preferred in applications due to their high strength-to-weight ratio, high-stiffness-to-weight ratio, high wear resistance, high corrosion resistance.The determination of mechanical properties is one of the important parts in composite materials research. Production method, materials used, and laminates configuration of the composites are among the contributing factors in changing the mechanical properties of composite materials. These properties are could not be found in any standard databases and tables. Conventional test procedures based on static loading are destructive, time and cost consuming. In addition, these tests often produce poor results especially in determining properties such as shear modulus. This has encouraged the development of specific methods to improve the accuracy in the identification method. Modal parameter such as mode shape or the combination of both natural frequencies and mode shapes are rarely used in elastic constants determination.In this paper, a non-destructive evaluation of the mechanical properties of composite materials which involves EMA and Finite Element (FE) model updating method is proposed. This approach utilises Background theories

Identification of material properties of composite materials using nondestructive vibrational evaluation approaches: A review

“…Thickness of plates also plays a cardinal role in deciding the use of appropriate plate theory in finite element modelling. Hence, collection of previous studies can be classified into thin isotropic [115,116], thin anisotropic [121,123], thin orthotropic [66,120,129], thin laminated plates [69,70,86,110,112,118,127] as well as thick anisotropic [122] and thick laminated plates [77, 78, 112-114, 117, 119, 124-126, 128, 130-132]. However, this procedure was not encouraged when the homogeneity of the material was the subject of investigation.…”

“…Natural frequencies or/and mode shapes are computed from the model for subsequent application in material determination process, as it can be observed in [66,69,70,77,78,83,86,. Studies are often done on rectangular [66, 69, 70, 77, 83, 86, 110-117, 119-124, 130] and square [77,78,110,115,116,118,125,126,[128][129][130] plates. Besides, there are also few studies done on plates of various geometrical shapes, as shown in [115,116].…”

“…Besides, there are also few studies done on plates of various geometrical shapes, as shown in [115,116]. In the aspect of boundary condition, plates with free-free edges [66,69,70,77,78,83,86,[110][111][112][113][114][115][116][117][118][119][120][121][122][123][124][125][126][127][128]130], simply-supported edges [110] and clamped edges [83,129] are often taken into investigation. Generally, laminated plates are utilized in previous studies [86,110,[112][113][114][117][118][119].…”

Development and validation of experimental modal analysis with fixture-free oblique impact testing based on a vector projection method

“…Frequency response function (FRF) testing and modal analysis (MA) are commonly used to identify the dynamic characteristics of a structure. These analyses were introduced several decades ago and have been applied to a wide range of engineering applications such as: validating and updating the finite element model [2,3], crack detection [4], damage identification [5], force identification [6], linear [7,8] and nonlinear [9] material property identification, vibration control and structural dynamic design [10]. In general, FRF testing experimentally determines the transfer function that shows a linear relationship between the input force and output response of the system.…”

Modal shape measurement of fiber-reinforced composite plate with high efficiency and precision based on laser linear scanning method

“…It was also proved that the more accurate vibration information of the composite plate can be acquired by the noncontact laser measurement technique. Kong et al 10 also used hammer excitation technique to obtain the modal shapes of the composite plate with the four edges clamped by some fixture tools. He found that the nodal lines of vibration shape were critical to the measurement.…”