Aeroelastic assessment of cracked composite plate by means of fully coupled finite element and Doublet Lattice Method

Abstract

This paper presents an investigation on flutter speed of cracked composite plates. This work is divided into two sections: (a) variation of crack length at a fixed location on the plate, and (b) variation of crack location on the plate with a fixed crack length, modelled as a unidirectional composite for 0 0 , 90 0 and 135 0 orientations. Mori-Tanaka homogenization model is applied to obtain the effective composite constitutive properties as the function of fiber and matrix volume fraction. Doublet Lattice Method (DLM) is used to calculate the unsteady aerodynamic forces, i.e., lift distributions. It is found that the existence of small crack ratio on the composite plate (less than 0.4) has triggered an increment of the flutter speed. To support this statement, flutter response modes for each crack ratio are plotted, where the structure appears to be more stiffened than the undamaged plate. However, the crack results in the reduction of flutter speed when the crack ratio reaches 0.5. For the crack location assessment, the flutter speed increases as the crack location moves from the root to the tip due to the reduction of flutter frequency. The results show a good agreement with the validation using Strip Theory considering unsteady aerodynamics.

Implementation of multiphase piezoelectric composites energy harvester on aircraft wingbox structure with fuel saving evaluation

“…One of the most well-known and the simplest homogenization method is the rule of mixture. The implementation of the Eshelby ′ s tensor with Mori-Tanaka method provides greater accuracy than the rule of mixture for large volume fraction [39].…”

An iterative finite element method for piezoelectric energy harvesting composite with implementation to lifting structures under Gust Load Conditions

“…Hence, a discrete segmentation of the piezoelectric layer may be required. Furthermore, considering the failure analysis, fracture and delamination in the piezoelectric composite laminates [59] may need to be addressed in the future, as well as the fracture during flight operation [60]. In addition, an evaluation on continuous gust or turbulence disturbance may also be considered for the future works.…”

Weight Function Method for Stress Intensity Factors of Semi-Elliptical Surface Cracks on Functionally Graded Plates Subjected to Non-Uniform Stresses

“…The newly derived weight functions of the surface, deepest and general points within the range of 0.2 ≤ a / c ≤ 1.0 and 0.1 ≤ a / t ≤ 0.8 are validated by comparing the analytical solutions in this study with the FE results for parabolic or cubic stress distributions, where a / c denotes the aspect ratio and a / t represents the crack depth ratio. The existing numerical results show that the crack length c , crack depth a and crack-tip location have a significant impact on the analysis results of crack problems [ 13 , 14 ]; therefore, a wide range of a / c (0.2, 0.4, 0.6, 0.8, 1.0) and a / t (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8) are assigned in FE models. According to reference [ 15 ], the condition of h / c = w / c 4 and t equal to a constant is defined in FE simulations, where h , t and w denote the half height, thickness and half width of the FG plate, respectively.…”