Delamination modeling in doubly curved laminated shells for free vibration analysis using zigzag theory‐based facet shell element and hybrid continuity method

Abstract

Summary We present a finite element (FE) formulation for the free vibration analysis of doubly curved laminated composite and sandwich shells having multiple delaminations, employing a facet shell element based on the efficient third‐order zigzag theory and the region approach of modeling delaminations. The methodology, hitherto not attempted, is general for delaminations occurring at multiple interfacial and spatial locations. A recently developed hybrid method is used for satisfying the continuity of the nonlinear layerwise displacement field at the delamination fronts. The formulation is shown to yield very accurate results with reference to full‐field three‐dimensional FE solutions, for the natural frequencies and mode shapes of delaminated shallow and deep, composite and highly inhomogeneous soft‐core sandwich shells of different geometries and boundary conditions, with a significant computational advantage. The accuracy is sensitive to the continuity method used at the delamination fronts, the usual point continuity method yielding rather poor accuracy, and the proposed hybrid method giving the best accuracy. Such efficient modeling of laminated shells with delamination damage will be of immense use for model‐based techniques for structural health monitoring of laminated shell‐type structures.

Analytical approach to study the vibration of delaminated multi‐scale composite cylindrical shells

“…Also CNTs forests were utilized in composite materials to sense and detect damage including delamination 10 . Kapuria and Ahmed 11 presented a finite element model (FEM) base on third‐order zigzag theory to study free vibration of doubly curved composite shell with multiple delaminations. There is good agreement between full field three‐dimensional solutions with obtained results.…”

Higher-order semi-layerwise models for doubly curved delaminated composite shells

“…The application of plate and shell theories to standard problems is well documented in the literature [14,43,44]. On the other hand, if the structure contains interlaminar cracks and delaminations, then the problem becomes significantly more complicated and its size increases considerably as well [45,46]. The related literature offers several analytical [47][48][49][50] and numerical [51,52] methodologies, respectively.…”