Crack Localization of Composite Plate Using Frequency Sensitivity Analysis Method

The free vibration sensitivity analysis of cracked composite plates is being numerically studied in this research. For this purpose, four parameters related to the crack, including the site of the crack in both horizontal and vertical directions, and the length and angle of the crack, were considered as input factors for free vibration sensitivity analysis of the composite plate. The range of input factors was selected, and based on that, the design of the experiment (DOE) was produced using the response surface method. The finite element method is employed to calculate the natural frequencies of cracked composite plates using the DOE. The cracked composite plate’s natural frequency sensitivity to each input factor was evaluated through dimensionless curves of natural frequency changes. The results show that the length and size of crack have remarkable and different effects on the first to fourth natural frequency of the composite plate. The implementation of effective interaction diagrams allows for localization of the crack on the composite plate. The results show that the input factors have different effects on the natural frequencies of cracked composite plates in modes 1 to 4. The sensitivity of input factors has nonlinear negative, negative downward trend, nonlinear positive, and nonlinear upward trend effects on the natural frequencies of cracked composite plates.