JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 52

wind energy

cycle at up to 200 rpm, which amasses to ~2.1x109 cycles over a 20-year design life. Over this period, the blade materials need to sustain large “normal operation” design loads which are fatigue loads. A fatigue assessment is thus a prerequisite for the design of a cost-effective blade. However, a noticeable lack of fatigue data on PFCs [8-11] limits their prospective use in fatigue-critical components (like SWTbs) as fatigue life prediction of the components is not possible. This study includes three aspects: i) evaluating the fatigue loads on a 3.5-metre study blade, as per bS-EN61400-2:2006, ii) constructing S-N diagrams and constant-life diagrams of PFCs for varying parameters, and iii) predicting the design life of a hemp/polyester composite blade. In prediction of the fatigue life, it is confirmed that the PFC blade satisfies the 20-year design life criteria, inclusive of a 1.50 safety factor.

Estimation of design fatigue loads The fatigue loads on the blade are estimated using the “Simplified load model” (Load case A) in bSEN61400-2:2006 [12]. The model states that the design load for “normal operation” is a fatigue load and that fatigue loading is considered to occur at the airfoil-root junction or at the root-hub junction (whichever has the lowest strength). From static testing of a full-scale prototype gFrP blade, static failure is found to occur at the root-hub junction. The PFC blade is assumed to fail similarly. Under Class II wind conditions (design wind speed = 11.9 m/s) and at a design rotor speed of 170 rpm, the fatigue loads at the root of a 25-kg hemp/polyester blade are found to be: - Centrifugal load, ΔFz = 25.3 kN - Edgewise bending moment, ΔMx = 1.03 kNm - Flapwise bending moment, ΔMy = 1.26 kNm The loads include a material partial safety factor of 1.25. The resultant tension-tension and compressioncompression fatigue stresses on the different constituents of the blade are then determined, as per bSEN61400-2:2006 [12]. These are presented in Table 1, showing that unidirectional (Ud) hemp/polyester experiences the most severe stresses.

Table 1: Fatigue stresses on different constituents at the blade root

Tensiontension
Maximum [MPa] Minimum [MPa] Mean [MPa] Amplitude [MPa] Stress ratio

Foam
1.3 0.4 0.9 0.5 0.29

Triax
21.1 6.2 14.9 7.5 0.29

UD
57.6 16.5 41.1 20.6 0.29

Compressioncompression
Maximum [MPa] Minimum [MPa] Mean [MPa] Amplitude [MPa] Stress ratio

Foam
-1.1 -0.4 -0.7 0.3 2.6

Triax
18.6 -7.1 -11.6 5.8 2.6

UD
-44.1 -17.4 -26.7 13.3 2.5

Blade fatigue load evaluation
Design summary of the PFC wind turbine blade The study blade is a 3.5-metre hemp/ polyester blade that is to be set-up on an 11-kW 3-bladed horizontal axis “Class II” small wind turbine at the University of Nottingham. The profile and lay-up of the blade are depicted in Fig. 3. The blade will be manufactured through a single-shot VArTM process in an aluminium mould tool.

Constant-life diagram for unidirectional hemp/polyester composites
Experimental Manufacture of composites: 3-3.3 mm thick unidirectional hemp yarn composites were manufactured through vacuum infusion in an aluminium mould tool. Hemp yarn (250 tex, 180 tpm) was sourced from Safilin (Poland). An orthophthalic unsaturated polyester (reichhold Norpol type 420-100) matrix was used. The resin was mixed with 0.25 wt% NL49P accelerator and 1 wt% butanox M50 initiator. Post-cure was carried out at 55°C for 6 hours after ambient cure for 16 hours. The density of the fibre, cured resin and composite were measured using helium pycnometry. The fibre and void volume fraction were then determined to be 35.6 ± 3.3 % and 1.4 ± 0.4 %, respectively. Static testing: Static tensile tests were conducted according to bSEN527-4:1997 using an Instron 5985 testing machine equipped with an exten-

Fig. 3: Profile and lay-up of the PFC blade

52 jec composites magazine / No73 June 2012



JEC COMPOSITES MAGAZINE - Issue #73 - June 2012

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #73 - June 2012

Cover
Edito
Point of view: core material
Contents
Agenda of Events
COMPANY & BUSINESS
- In Brief
- Reinforcement
- Book launch
APPLICATIONS
- Railway
- UAV
- Electric vehicule
MARKET
- Human ressources
- Sandwich
SPECIAL JEC ASIA 2012
- Floor plan
- Conferences
- JEC Asia Innovation Awards Programme
- Innovation report
- Country guest of honour: Malaysia
- Reinforcement
- Wind energy
RESEARCH & DEVELOPMENT
- Design
- Automation
TECHNOLOGY & INNOVATIONS
- Reinforcement
- UPR
- Mirco-pultrusion
- Pultrusion
- Injection
- Certification
Index
In the world
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - Cover
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 2
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - Edito
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - Point of view: core material
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 5
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - Contents
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 7
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - Agenda of Events
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - In Brief
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Reinforcement
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 11
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Book launch
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 13
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Railway
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 15
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - UAV
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Electric vehicule
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 18
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Human ressources
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Sandwich
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 21
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 22
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 23
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Floor plan
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 25
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Conferences
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 27
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 28
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 29
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - JEC Asia Innovation Awards Programme
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 31
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 32
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 33
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Innovation report
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 35
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 36
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 37
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 38
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Country guest of honour: Malaysia
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 40
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 41
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 42
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 43
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 44
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 45
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 46
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 47
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Reinforcement
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 49
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 50
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Wind energy
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 52
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 53
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 54
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Design
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 56
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 57
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 58
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Automation
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 60
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 61
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 62
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 63
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 64
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 65
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Reinforcement
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 67
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - UPR
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 69
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 70
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Mirco-pultrusion
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 72
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 73
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Pultrusion
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 75
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Injection
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - - Certification
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 78
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 79
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 80
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - Index
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - In the world
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 83
JEC COMPOSITES MAGAZINE - Issue #73 - June 2012 - 84
https://www.nxtbook.fr/newpress/jeccomposites/jcm2109_142
https://www.nxtbook.fr/newpress/jeccomposites/jcm2107_141
https://www.nxtbook.fr/newpress/jeccomposites/jcm2105_140
https://www.nxtbook.fr/newpress/jeccomposites/jcm2103_139
https://www.nxtbook.fr/newpress/jeccomposites/jcm-experts-digest-additive-manufacturing-2020
https://www.nxtbook.fr/newpress/jeccomposites/jcm2101_138
https://www.nxtbook.fr/newpress/jeccomposites/jcm2011_Special_Issue4
https://www.nxtbook.fr/newpress/jeccomposites/jcm2011_137
https://www.nxtbook.fr/newpress/jeccomposites/jcm2009_136
https://www.nxtbook.fr/newpress/jeccomposites/jcm2007_135
https://www.nxtbook.fr/newpress/jeccomposites/jcm_2020_Q1_Innovation_Report
https://www.nxtbook.fr/newpress/jeccomposites/jcm2005_Special_Issue3
https://www.nxtbook.fr/newpress/jeccomposites/jcm2005_134
https://www.nxtbook.fr/newpress/jeccomposites/jcm2003_133
https://www.nxtbook.fr/newpress/jeccomposites/jcm2001_132
https://www.nxtbook.fr/newpress/jeccomposites/jcm1911_Special_Issue2
https://www.nxtbook.fr/newpress/jeccomposites/jcm1911_131
https://www.nxtbook.fr/newpress/jeccomposites/jcm1909_130
https://www.nxtbook.fr/newpress/jeccomposites/jcm1907_129
https://www.nxtbook.fr/newpress/jeccomposites/jcm1905_128
https://www.nxtbook.fr/newpress/jeccomposites/jcm1903_Special_Issue1
https://www.nxtbook.fr/newpress/jeccomposites/jcm1903_127
https://www.nxtbook.fr/newpress/jeccomposites/jcm1901_126
https://www.nxtbook.fr/newpress/jeccomposites/jcm1811_125
https://www.nxtbook.fr/newpress/jeccomposites/jcm1810_124
https://www.nxtbook.fr/newpress/jeccomposites/jcm1808_123
https://www.nxtbook.fr/newpress/jeccomposites/jcm1807_122
https://www.nxtbook.fr/newpress/jeccomposites/jcm1805_121
https://www.nxtbook.fr/newpress/jeccomposites/jcm1804_120
https://www.nxtbook.fr/newpress/jeccomposites/jcm1803_119
https://www.nxtbook.fr/newpress/jeccomposites/jcm1802_119-Supplement_Innovation_Report
https://www.nxtbook.fr/newpress/jeccomposites/jcm1801_118
https://www.nxtbook.fr/newpress/jeccomposites/jcm1711_117
https://www.nxtbook.fr/newpress/jeccomposites/jcm1710_116
https://www.nxtbook.fr/newpress/jeccomposites/jcm1708_115
https://www.nxtbook.fr/newpress/jeccomposites/jcm1707_114
https://www.nxtbook.fr/newpress/jeccomposites/jcm1706_113
https://www.nxtbook.fr/newpress/jeccomposites/jcm1704_112
https://www.nxtbook.fr/newpress/jeccomposites/jcm1703_111
https://www.nxtbook.fr/newpress/jeccomposites/jcm1701_110
https://www.nxtbook.fr/newpress/jeccomposites/jcm1611_109
https://www.nxtbook.fr/newpress/jeccomposites/jcm1610_108
https://www.nxtbook.fr/newpress/jeccomposites/jcm1608_107
https://www.nxtbook.fr/newpress/jeccomposites/jcm1607_106
https://www.nxtbook.fr/newpress/jeccomposites/jcm1605_105
https://www.nxtbook.fr/newpress/jeccomposites/jcm1604_104
https://www.nxtbook.fr/newpress/jeccomposites/jcm1603_103
https://www.nxtbook.fr/newpress/jeccomposites/jcm1601_102
https://www.nxtbook.fr/newpress/jeccomposites/jcm1511_101
https://www.nxtbook.fr/newpress/jeccomposites/jcm1510_100
https://www.nxtbook.fr/newpress/jeccomposites/jcm1509_99
https://www.nxtbook.fr/newpress/jeccomposites/jcm1507_98
https://www.nxtbook.fr/newpress/jeccomposites/jcm1505_97
https://www.nxtbook.fr/newpress/jeccomposites/jcm1504_96
https://www.nxtbook.com/newpress/jeccomposites/jcm1503_95
https://www.nxtbook.com/newpress/jeccomposites/jcm1501_94
https://www.nxtbook.com/newpress/jeccomposites/jcm1412_93
https://www.nxtbook.com/newpress/jeccomposites/jcm1410_92
https://www.nxtbook.com/newpress/jeccomposites/jcm1409_91
https://www.nxtbook.com/newpress/jeccomposites/jcm1406_90
https://www.nxtbook.com/newpress/jeccomposites/jcm1405_89
https://www.nxtbook.com/newpress/jeccomposites/jcm1404_88
https://www.nxtbook.com/newpress/jeccomposites/jcm1403_87
https://www.nxtbook.com/newpress/jeccomposites/jcm1401_86
https://www.nxtbook.com/newpress/jeccomposites/jcm1311_85
https://www.nxtbook.com/newpress/jeccomposites/jcm1310_84
https://www.nxtbook.com/newpress/jeccomposites/jcm1308_83
https://www.nxtbook.com/newpress/jeccomposites/jcm1307_82
https://www.nxtbook.com/newpress/jeccomposites/jcm1305_81
https://www.nxtbook.com/newpress/jeccomposites/jcm1304_80
https://www.nxtbook.com/newpress/jeccomposites/jcm1303_79
https://www.nxtbook.com/newpress/jeccomposites/jcm1301_78
https://www.nxtbook.com/newpress/jeccomposites/jcm1212_77
https://www.nxtbook.com/newpress/jeccomposites/jcm1210_76
https://www.nxtbook.com/newpress/jeccomposites/jcm1208_75
https://www.nxtbook.com/newpress/jeccomposites/jcm1207_74
https://www.nxtbook.com/newpress/jeccomposites/jcm1206_73
https://www.nxtbook.com/newpress/jeccomposites/jcm1204_72
https://www.nxtbook.com/newpress/jeccomposites/jcm1203_71
https://www.nxtbook.com/newpress/jeccomposites/jcm1201_70
https://www.nxtbook.com/newpress/jeccomposites/jcm1111_69
https://www.nxtbook.com/newpress/jeccomposites/jcm1110_68
https://www.nxtbook.com/newpress/jeccomposites/jcm1108_67
https://www.nxtbook.com/newpress/jeccomposites/jcm1107_66
https://www.nxtbook.com/newpress/jeccomposites/jcm1105_65
https://www.nxtbook.com/newpress/jeccomposites/jcm1104_64
https://www.nxtbook.com/newpress/jeccomposites/jcm1103_63
https://www.nxtbook.com/newpress/jeccomposites/jcm1101_62
https://www.nxtbook.com/newpress/jeccomposites/jcm1011_61
https://www.nxtbook.com/newpress/jeccomposites/jcm1010_60
https://www.nxtbook.com/newpress/jeccomposites/jcm1009_59
https://www.nxtbook.com/newpress/jeccomposites/jcm1006_58
https://www.nxtbook.com/newpress/jeccomposites/jcm1005_57
https://www.nxtbook.com/newpress/jeccomposites/jcm1004_56
https://www.nxtbook.com/newpress/jeccomposites/jcm1003_55
https://www.nxtbook.com/newpress/jeccomposites/jcm1001_54
https://www.nxtbook.com/newpress/jeccomposites/jcm0911_53
https://www.nxtbook.com/newpress/jeccomposites/jcm0910_52
https://www.nxtbook.com/newpress/jeccomposites/jcm0909_51
https://www.nxtbook.com/newpress/jeccomposites/jcm0907-08_50
https://www.nxtbook.com/newpress/jeccomposites/jcm0906_49
https://www.nxtbook.com/newpress/jeccomposites/jcm0904_48
https://www.nxtbook.com/newpress/jeccomposites/jcm0903_47
https://www.nxtbook.com/newpress/jeccomposites/jcm0901_46
https://www.nxtbook.com/newpress/jeccomposites/jcm0811_45
https://www.nxtbook.com/newpress/jeccomposites/jcm0810_44
https://www.nxtbook.com/newpress/jeccomposites/jcm0809_43
https://www.nxtbook.com/newpress/jeccomposites/jcm0807_42
https://www.nxtbook.com/newpress/jeccomposites/jcm0806_41
https://www.nxtbook.com/newpress/jeccomposites/jcm0805_40
https://www.nxtbook.com/newpress/jeccomposites/jcm0803_39
https://www.nxtbook.com/newpress/jeccomposites/jcm0801_38
https://www.nxtbook.com/newpress/jeccomposites/jcm0712_37
https://www.nxtbook.com/newpress/jeccomposites/jcm0710_36
https://www.nxtbook.com/newpress/jeccomposites/jcm0709_35
https://www.nxtbook.com/newpress/jeccomposites/jcm0707_34
https://www.nxtbook.com/newpress/jeccomposites/jcm0706_33
https://www.nxtbookmedia.com