FAILURE MODE TRANSITION DURING DELAMINATION OF THICK UNIDIRECTIONAL L-SHAPED COMPOSITE LAMINATES

2012-11-15
Yavas, Denizhan
Gozluklu, Burak
Çöker, Demirkan
Curved composite laminates such as L-beams are frequently used in wind turbine blade structures such as spars and ribs. It is widely assumed that delamination initiates at the curved region of the L-shaped laminate leading to loss of loading carrying capacity. However, as shown in this paper, under certain conditions a second failure mode in thick L-shaped laminates is observed in which a secondary crack initiates at the arm region. Delamination in L-shaped laminates is modeled using a sequential analysis with implicit analysis followed by explicit dynamic (explicit) finite element analysis in conjunction with cohesive zone methods. The 2-D model consists of 24 plies of unidirectional CFRP laminate with an initial crack at the center of curved region. Loading is applied parallel to one arm quasi-statically and the observed delamination occurs dynamically. For thin laminates and larger precracks, delamination starts from the initial crack and propagates towards the arms. For thicker L-shaped laminates and smaller precracks at the center of curved region, formation of secondary crack in the arm region is observed. Therefore the size of the initial crack as a function of thickness at the center of the curved region mainly decides the failure mode.
ASME International Mechanical Engineering Congress and Exposition

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Citation Formats
D. Yavas, B. Gozluklu, and D. Çöker, “FAILURE MODE TRANSITION DURING DELAMINATION OF THICK UNIDIRECTIONAL L-SHAPED COMPOSITE LAMINATES,” presented at the ASME International Mechanical Engineering Congress and Exposition, Houston, TX, 2012, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/53199.