Final report for WP4.3: Enhancement of design methods ... - Upwind

More documents

Recommendations

Info

UPWIND WP4: Offshore Support Structures and Foundations The third test case considered a complete wind turbine structure consisting of a three blade rotor supported by a tubular steel tower. Again, the lowest mode shapes were calculated and compared with respect to frequency and shape. Full results are given in [98], and indicate an excellent agreement between the modes calculated by ANSYS and Bladed v4.0. 1 DISPLACEMENT STEP=1 SUB =3 FREQ=.377211 DMX =.003682 Y Z X SEP 3 2010 16:09:59 Figure 7.1: Mode shape 2 of the complete wind turbine structure calculated by ANSYS (above) and Bladed v4.0 (below) 86 1 DISPLACEMENT STEP=1 SUB =15 FREQ=4.146 DMX =.044085 Z X Y SEP 3 2010 15:54:37 Figure 7.2: Mode shape 14 of the complete wind turbine structure calculated by Ansys (above) and Bladed v4.0 (below). In the third level of testing a code-to-code comparison was performed using test cases from phase I of the OC3 project [15], modelling a 5MW offshore turbine mounted on a monopile support structure. Figure 7.3 presents the natural frequencies of the complete system calculated by GH Bladed Multibody, together with the average over all the participant codes. The error bars show the standard deviation in frequency between the different codes. Two series are shown for the natural frequencies because the results differ substantially depending on whether the yaw degree of freedom of the support structure has been included in the calculation, especially for the 2 nd blade asymmetric flapwise yaw mode. Good agreement is seen for the both cases, with or without the tower torsion mode included. Figure 7.4 presents time histories of the tower base bending moment due to wave loads. Differences in higher frequency may be due to differences in damping of transient structural vibrations. Overall the results for the complete wind turbine show good agreement with other simulation codes, which include modal, multibody and finite element structural models.
UPWIND WP4: Offshore Support Structures and Foundations Natural Frequency, Hz Tower base bending moment, kNm 2.5 2.0 1.5 1.0 0.5 0.0 1st Tower Fore-Aft 1st Drivetrain Torsion 1st Tower Side-to-Side 30000 20000 10000 0 -10000 -20000 -30000 1st Blade Collective Flap 1st Blade Asymmetric Flapwise Yaw 1st Blade Asymmetric Flapwise Pitch 1st Blade Asymmetric Edgewise Yaw 1st Blade Asymmetric Edgewise Pitch 2nd Tower Fore-Aft 87 2nd Tower Side-to-Side 2nd Blade Collective Flap 2nd Blade Asymmetric Flapwise Yaw 2nd Blade Asymmetric Flapwise Pitch Figure 7.3: Comparison of natural frequencies [98] Average over codes (including yaw degree of freedom) Average over codes (excluding yaw degree of freedom) GH BladedMultibody GH BladedMultibody + Torsion 40 45 50 55 60 Simulation Time, s Figure 7.4: Comparison of tower base bending moment, regular waves [98] In the fourth level of testing a number of complete fatigue and extreme load sets were performed using Bladed v4.0 and compared against equivalent load sets calculated using previous versions of Bladed. The previous GH Bladed code was extensively validated against measured data from a large number of turbines of different sizes and configurations [9], so these internal comparisons are an important check. In total, five complete loadsets were compared, covering a range of different turbine types and configurations: • Multi-megawatt, offshore, 3-blade, multi-member support structure, upwind, variable speed, pitch regulated • Multi-megawatt, onshore, 3-blade, monopile tower, upwind, variable speed, pitch regulated
Page 1 and 2:
Project UpWind Contract No.: 019945
Page 3 and 4:
Acknowledgement The presented work
Page 5 and 6:
Summary The overall aim of the UpWi
Page 7:
Table of Contents Acknowledgement..
Page 10 and 11:
Task 4.1 Integration of support str
Page 12 and 13:
Sequential coupling The sequential
Page 14 and 15:
analysis. In the new multibody code
Page 16 and 17:
Figure 2.4: 2nd global bending mode
Page 18 and 19:
3.2 Comparison of deterministic loa
Page 20 and 21:
Figure 3.5: Time series of axial fo
Page 22 and 23:
• Time domain simulation in ADCoS
Page 24 and 25:
• A supplementary load vector for
Page 26 and 27:
The following results are found: Fi
Page 28 and 29:
Figure 4.5: Output positions in the
Page 30 and 31:
It is directly visible that there i
Page 32 and 33:
ated eigenfrequency is shifted into
Page 34 and 35:
Water levels For the calculation of
Page 36 and 37: guidelines for the inclusion of cli
Page 38 and 39: damaging if the frequency of the ex
Page 40 and 41: uncertain parameters carefully. Thr
Page 42 and 43: Table 5.3 shows annual reliability
Page 44 and 45: Steel substructure for offshore win
Page 46 and 47: Table 5.16 shows the required FDF v
Page 48 and 49: A Fracture Mechanical (FM) modellin
Page 50 and 51: Figure 5.4: Annual reliability indi
Page 52 and 53: Further, the effect of possible ins
Page 54 and 55: Rainflow evaluation The load cases
Page 56 and 57: For DLC 7.2 it has to be considered
Page 58 and 59: Guideline, DLC 1.5). Furthermore, t
Page 60 and 61: Table 5.28: Output locations for da
Page 62 and 63: From these results it can be clearl
Page 64 and 65: Figure 5.11: Normalised DELs with v
Page 66 and 67: Figure 5.14 presents normalized DEL
Page 68 and 69: Figure 5.16: Output locations for e
Page 70 and 71: UPWIND WP4: Offshore Support Struct
Page 136 and 137:
UPWIND WP4: Offshore Support Struct
Page 138 and 139:
Page 140 and 141:
Page 142 and 143:
Page 144 and 145:
show all

Final report for WP4.3: Enhancement of design methods ... - Upwind

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?