Delamination identification of laminated composite plates using a continuum damage mechanics model and subset selection technique

Abstract

In this paper, a new model-based delamination detection methodology is presented for laminated composite plates and its performance is studied both numerically and experimentally. This methodology consists of two main parts: (1) modal analysis of an undamaged baseline finite element (FE) model and experimental modal testing of panels with delamination damage at single or multiple locations and (2) a sensitivity based subset selection technique for single or multiple delamination damage localizations. As an identification model, a higher-order finite element model is combined with a rational micromechanics-based CDM model which defines the delamination damage parameter as a ratio of delaminated area to entire area. The subset selection technique based on sensitivity of the dynamic residual force has been known to be capable of detecting multiple damage locations. However, there has been no experimental study specifically for the applications in laminated composite structures. To implement the methodology, a sensitivity matrix for the laminated composite plate model has been derived. Applications of the proposed methodology to an E-glass/epoxy symmetric composite panel composed of 16 plies [CSM/UM1208/3 layers of C1800] s = [CSM/0/(90/0) 3 ] s with delamination damage are demonstrated both numerically and experimentally. A non-contact scanning laser vibrometer (SLV), a lead zirconate titanate (PZT) actuator and a polyvinylidene fluoride (PVDF) sensor are used to conduct experimental modal testing. From the experimental example, capabilities of the proposed methodology for damage identification are successfully demonstrated for a 2D laminated composite panel. Furthermore, various damage scenarios are considered to show its performance and detailed results are discussed for future improvements.

A Damage Model for Adhesively Bonded Single-Lap Thick Composite Joints

“…The damage initiation criteria for the composite adherend are based on Hashin's theory [27,28]. The damage initiation in fiber is indicated by F/ > 1, and the damage initiation in matrix is indicated by E", > 1, where >0 <0 (8) 25V (9) where Ef and E" are damage initiation indicators of fiber and matrix, respectively. X^ and X*-are, respectively, the longitudinal tensile and compressive strength.…”

“…Numerous researchers [1][2][3][4][5][6][7][8][9][10] have focused on experimental methods to detect delamination of laminated composite. For example, Kessler et al [3] and Shang et al [9] used Lamb wave methods for delamination identification, whereas Kessler et al [4] used frequency response methods, and Kyriazoglou et al [5] adopted vibration damping to detect crack. Some of these methods were effective for a respective model; they provide a basis for theoretical modeling for bonded composite joints.…”

“…On the other hand, Refs. [17][18][19][20][21] employed the fracture mechanics approach to investigate a delamination behavior, whereas the continuum mechanics approach [9,[22][23][24][25] was used to investigate the same issue. Generally speaking, closed form solutions are not easy to obtain, and the limitations introduced by some simplifying assumptions would often restrict their general applicability, especially in systems with plastic deformation and damage, such as voids, defects, delamination, and imperfections.…”

Non-baseline identification of delamination in plates using wavelet-aided fractal analysis of two-dimensional mode shapes

“…Sohn et al (2011b) created a signal and image processing algorithm for automatically detecting delamination and disbonding in composite plates, with the merits and the limitations of the algorithm fully presented. Shang et al (2010) developed a model-based delamination detection methodology using the continuum damage mechanics model and a subset selection technique. Applications of the proposed methodology to an E-glass/ epoxy symmetric composite panel with delamination damage were demonstrated numerically and experimentally.…”

Stochastic Galerkin model updating of randomly distributed parameters

“…Model updating in the field of structural health monitoring (SHM) is continuously under development and has acquired a wide recognition over the last few decades [1][2][3] . Essentially, it aims to improve predictive capabilities of the numerical model by comparing the numerical response of structures to experimentally observed responses.…”