Abstract
The paper presents a case study on the causes that led to the breaking of the blades on a 5 kW wind turbine due to high wind loads at a wind speed of 30 m/s . The paper is structured in two parts. In the first part there are presented the functional design and material aspects essential for a blade proper operation, with an analysis of the critical areas where the breaking of the blade was initiated. There are also analyzed the causes the materials prescribed in the technical design and the manufacturing technology failed upon a short time wind gust of up to 30m/s. In the second part of the paper there are presented corrective technical solutions for materials and blade shape design in order to ensure a higher mechanical strength of the blade suitable for a safe and reliable operation for the specific environmental conditions. The studies and the solutions considered for the blade design improvement shown in the present paper are based on finite element analysis (FEA) as well as on blade static tests performed by using distributed sandbag loads. Keywords: wind turbine, blade, wind speed, GFRP, Finite Element Analysis, load, stress