A Quantitative Study on the Void Defects Evolving into Damage in Wind Turbine Blade Based on Internal Energy Storage

Abstract

As manufacturing defects, voids in wind turbine blades may cause damage under fatigue loads. In this paper, the internal energy storage is used as an indicator to identify the critical moment when a defect evolves into damage. The heat transfer equation of composites material containing void defects is derived based upon the theory of the thermodynamics of irreversible processes. In order to obtain the numerical calculation model of the internal energy storage of the evolving process, the thermal conductivity along the transverse direction is homogenized as the temperature date along this direction is acquired by a thermal camera. Specimens with different void fractions are tested with infrared thermal imaging under fatigue load, during which the stress, strain and temperature data are acquired to establish the curve of internal energy storage against the fatigue cycle. This relationship curve can be used to identify the critical moment when void defects evolve into damage. The feasibility of this method is proven by microscopic observation.

Quality Control Approach for the Detection of Internal Lower Density Areas in Composite Disks in Industrial Conditions Based on a Combination of NDT Techniques

“…However, the sensitivity of IRT is suitable for the detection and identification of subsurface defects, such as lower density areas, which was confirmed in numerous previous studies (see e.g. [65][66][67]), including inspection of thick composite structures, such as wind turbine blades. The following observations were made during testing using this technique:…”

Predictive Data Mining Techniques for Fault Diagnosis of Electric Equipment: A Review

“…Also, special attention has to be given to equipment related to renewable energy sources such as wind turbines, photovoltaic systems, power converters, energy storage systems, among others, due to their rapid development and growth [135,136]. For instance, the void defects evolving into damage in wind turbine blades are investigated in [137]. The improvement of photovoltaic and wind power storage systems based on the prediction of battery life and its faults using SVMs is presented in [138]; in these systems, the correct operation of batteries is fundamental.…”

A new two-step modeling strategy for random micro-fiber reinforced composites with consideration of primary pores

“…Compared with traditional homogeneous materials, random micro fiber-reinforced composites exhibit excellent toughness, which have been widely used in both composite sheet molding and bulk molding compounds [1][2][3][4]. One of the important influencing factors in evaluating mechanical properties of composites is the existence of primary pore defects that are introduced inevitably during material processing [5][6][7]. Pore defects not only have a significant effect on the mechanical properties [8][9] of a composite, but also increase uncertainty of damage evolution in the composite [10][11][12].…”