Trans RINA, Vol 152, Part B2, Intl J Small Craft Tech, 2010 Jul-Dec
load), 587sec (17%), 639sec (26%) and final collapse at 720 sec (1800N). Up to 26% of ultimate load, the load deflection plot was linear (until this point, the stiffness of the structure remained constant). At this point, all the CSM and DB layers were completely damaged and were incapable of higher load increments. Unidirectional fibres carried the entire load until final collapse. The residual strength of the unidirectional fibres was demonstrated by, carrying the majority of the load even after the failure of other layers. This is the primary motive of using unidirectional layers in FRP marine structures, failure.
to hold the structure in position beyond 4.4
DISCUSSION OF EXPERIMENTAL RESULTS
The stiffness of the first layup (all CSM) was higher than the other two layups. The second layup (CSM + DB) experienced reduced stiffness compared to the other two layups. The addition of the double bias (±450) layers added more flexibility to the structure. Odd numbers of layers were chosen to avoid the location of neutral axis exactly between the layers, so as to obtain a better failure study. Interestingly, the initial delamination was observed between the second and third layer irrespective of the layup and therefore it is assumed to be the region of highest interlaminar stress.
Figure 5.1: Progressive failure of Layup 3 specimens
Figure 5.2: Load-deflection plot for Layup 3 specimens
©2010: The Royal Institution of Naval Architects
B-101
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66