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

Abstract

The laser linear scanning method is proposed to measure the modal shape of fiber-reinforced composite thin plate with high efficiency and precision. First, by establishing the laser scanning frame model of the composite plate, the corresponding extraction principle of modal shape data and laser scanning rate selection criterion are explained in detail to clarify the theoretical principle of laser linear scanning method. The corresponding test procedure of modal shape, drawing method from the shape scanning data, and control method of the constant laser scanning rate are also proposed based on the developed laser linear scanning system. Then, a TC300 carbon fiber/resin composite thin plate is taken as a research object to verify the effectiveness and reliability of such a method, through comparing the results obtained by the traditional experimental modal method and finite element method. Moreover, the influences of constraint boundary condition, excitation level, laser scanning rate, scanning spacing, scanning path mode, the fiber angles, and fiber material damage on modal shape results are also discussed. It has been found that laser linear scanning method can improve test efficiency of modal shape of the composite plate with high preciseness. Except for scanning path mode, the other parameters have a major impact on each shape morphology, and their effects can be quantitatively analyzed by identifying the positions and clarity of nodal lines of each modal shape. Especially, the high-density modal shape results and their equal amplitude lines in different projection views can be used to determine whether or not the composite plate is damaged as well as its damaged degrees.

Effects of Surface-Parallel Edge Restraints and Inter-laminar Shear on the Responses of Doubly Curved General Cross-Ply Panels

“…Several researchers, e.g., [62,[106][107][108], have published their experimental findings that endeavored to verify analytical predictions, such as mentioned above. More detailed reviews on this topic are available elsewhere [88], and will not be repeated here in the interest of brevity of presentation.…”

“…Fifth, experimental results are needed to validate the present as well as other higher order shear deformation theory based models for laminated anisotropic panels of negative Gaussian curvature, in a manner that can be considered as extensions of Refs. [62,[106][107][108]127].…”

An Amplitude- and Temperature-Dependent Vibration Model of Fiber-Reinforced Composite Thin Plates in a Thermal Environment

“…The laser beam produced by the vibrometer was employed to measure the response of the plates. The path of the laser spot is controlled by a two-dimensional scanning device programmed by LabVIEW 2013, by which way the test efficiency can be improved significantly, especially that of the measurements of modal shapes in thermal field [50]. An accelerometer was employed to measure the basic excitation generated by the electromagnetic exciter and power amplifier.…”

“…Then, the natural frequencies of composite plate A were identified by picking the peaks in the corresponding frequency spectrum, as shown in Table 1. Then, by inputting each natural frequency value in the LMS Test.Lab 2014 10B software to excite the plate specimen at the resonance state, each modal shape at room temperature was consequently measured by the laser linear scanning method [50] (also shown in Table 3). By repeating the above test procedures, the natural frequencies and modal shapes under different temperatures and excitation amplitudes were acquired.…”

“…So, we will not discuss modal shapes in the following measurements. 2014 10B software to excite the plate specimen at the resonance state, each modal shape at room temperature was consequently measured by the laser linear scanning method [50] (also shown in Table 3). By repeating the above test procedures, the natural frequencies and modal shapes under different temperatures and excitation amplitudes were acquired.…”