Applying static and dynamic test responses for defect prediction in wind turbine blades using a probabilistic approach

This paper presents a novel approach in the field of experimental and numerical investigation of mechanical properties of composite structures. It takes into account test data variability resulting from structural dynamic properties measurement. The main goal of the conducted research is to investigate the dynamic and static properties of fiber reinforced composite structure towards assessment of accuracy of the damage detection. Non-destructive experimental and numerical simulation methods are used hereto. In the experimental part static and dynamic test were performed. The dynamic excitation was performed by means of random single point stimuli while the response measurement was done through contact acceleration sensing. In the static test four point bending configuration was implemented. Applied force and strain response was measured. The test results are applied in two ways: for the structural identification of the object and for non-deterministic updating of the numerical model according to a range of experimental models obtained from test. The sources of the test data variabilities were related to the specimen-to-specimen and test-to-test of the investigated object. Non–deterministic model updating and validation included uncertainties of its parameters by means of probabilistic methods. A number of variable test modal models were statistically assessed to investigate impact of variability source onto clarity of damage identification. Then, for each of investigated specimens an individual damage scenario was introduced. Two different vibration based methods were applied for the damage detection. The results are presented and compared. The research was conducted in the context of the FP7 project PROND.