초록

The composite blade is one of the main components of a wind turbine. Unfortunately, composite blades may have internal damage such as debonding, cracks, and delamination resulting from the manufacturing process or external fatigue loads. Among these damage modes, debonding damage occurring between the spar cap and shear web is the most significant damage mode. Therefore, it is necessary to analyze the mechanism of debonding damage in spar cap-shear web adhesive joints of composite blades. For this purpose, it is required to analyze the mechanical properties considering the lamination pattern and contact conditions of the composite blades used in wind turbines. In particular, wind turbine blades receive a combined load, and the crack growth characteristics of the joint differ according to the combined load characteristics. In this study, to analyze the mechanism of joint damage under a combined load, for Mode I (Double Cantilever Beam, or DCB), Mode II ( End-Notched Flexure, or ENF) and Mode I/Mode II (Mixed Mode Bending, or MMB) specimens were designed based on ASTM D5528, D7905 and D6671 standards. Tests were performed with Mode I, Mode II and Mixed mode to obtain the interlaminar fracture toughness. Finally, the FE analysis was carried out for the Mode I specimen using the cohesive zone modeling (CZM) method to simulate the debonding damage growth mechanism.

키워드

쌍외팔보, 노치굽힘, 유리섬유강화복합재, 층간파괴인성, 2축/3축 적층하이브리드, 혼합굽힘

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