NREL5MW

[EVElove444]

Hello, thank you very much for providing the yaml file of NREL5MW, but I am not sure if the data in NREL5MW is consistent with the Pucheng structure data of OpenFast or SNL61.5m blades? Because we need a baseline blade as a reference to optimize the blade structure.

[ptrbortolotti]

The original design of the SNL61.5 has been imported to windIO to the best of out ability. I am not sure how the BeamDyn file of the NREL5MW was originally developed, but I believe it relied on quite a few assumptions. Overall, we don't expect a 1-1 match between the K and I matrices predicted by SONATAmini from @KIDEVLIN and the older BeamDyn file, nor to the older SNL61.5 data from NuMAD

[ptrbortolotti]

hello, I'm sorry, please reformulate your question as I don't understand what you need

[EVElove444]

Dear KIDEVLIN,

I hope this message finds you well.

I am currently conducting research using the NREL 5MW reference wind turbine model, with a particular focus on the accuracy of the 6x6 stiffness and mass matrices in the BeamDyn module. I have a few questions that I hope you can assist me with:

Verification of Stiffness and Mass Matrices:
How can we ensure that the 6x6 stiffness and mass matrices for the NREL 5MW turbine in BeamDyn are accurate? Are there recommended methods or steps to validate these matrices?

Source of Structural Parameters:
Could you provide details about the source or basis for the structural parameters used for the NREL 5MW turbine? Are these parameters derived from specific experimental data or simulation results?

Related Literature or Documentation:
Are there any publications, technical reports, or documentation that detail the structural parameters of the NREL 5MW turbine and their application in BeamDyn? Such references would be invaluable for understanding and validating the physical characteristics of the model.

Thank you for taking the time to read this email. I look forward to any information you can provide to ensure the accuracy of my research model. Please let me know if you need any further details.

Best regards,

[KIDEVLIN]

Hello,

Verification of Stiffness and Mass Matrices:
The accuracy of the 6x6 stiffness and mass matrices produced by SONATAmini with ANBA4 were verified using a box-beam example here. For a wind turbine application, a comparison using the IEA 22 MW RWT between SONATAmini and a separate cross-sectional solver from DTU produced similar results. I am unaware of any comparisons of the stiffness and mass matrices for the NREL 5 MW. I would visually check the meshing in the cross-sections produced by SONATAmini to ensure accurate results.

Source of Structural Parameters:
The original structural properties found here on page 5, were based on a similar-sized LM Glassfiber blade. The internal structure of the 5 MW turbine in the yaml file is based on this paper which defines a shell model of the blade.

[EVElove444]

Dear Sir,

I hope this message finds you well.
blade_section_0.4137931034482759.pdf

I am currently working on calculating the structural information of a blade using Sonata. During the process, I modified the aerodynamic shape of the blade. However, I have encountered an issue where the mesh quality for one of the blade sections is very poor, while the other sections are satisfactory, as shown in the attached image.

Despite my attempts to resolve this issue by reducing the minimum size and adjusting the mesh generation parameters, the problem persists for this specific section. The error continues to affect the quality of this section's mesh significantly.

Could you please provide guidance on how to address this problem?

Thank you very much for your assistance.

Best regards,

[EVElove444]

Could you please clarify why there is a discrepancy between the airfoil distributions in the YAML file and the design manual? Is there a specific reason for this difference?

[EVElove444]

Dear Sir,

I hope this message finds you well. blade_section_0.4137931034482759.pdf

I am currently working on calculating the structural information of a blade using Sonata. During the process, I modified the aerodynamic shape of the blade. However, I have encountered an issue where the mesh quality for one of the blade sections is very poor, while the other sections are satisfactory, as shown in the attached image.

Despite my attempts to resolve this issue by reducing the minimum size and adjusting the mesh generation parameters, the problem persists for this specific section. The error continues to affect the quality of this section's mesh significantly.

Could you please provide guidance on how to address this problem?

Thank you very much for your assistance.

Best regards,

@KIDEVLIN

[KIDEVLIN]

Hello,

The yaml file was changed because the original yaml file was based on a shell method instead of the solid method that SONATA uses. The shell method defines each layer as a 1D line with a "thickness" which can result in overlapping 2D shapes in the solid method as seen in the picture below. The overlap causes issues in SONATA. To fix this, the trailing edge foam thickness was reduced by half at all radial stations.

If the warning "WARNING: No closed section found in segment 0. Segment has been closed." is displayed, the segment of code below in the converter_WT.py file is causing the meshing error. This code was a fix for inputs with layups that have no materials starting at 0 or ending at 1 leading to an open airfoil. The fix finds layups with starts and ends close to 0 and 1 and sets them to 0 and 1. You can fix your meshing issue by checking that the yaml input layup has materials starting and closing at 0 and 1. Another fix could be playing with the tolerances in this code block.

# Finding the minimum start and maximum end value for the layers in each starting segment and assigning starts
# and ends within a tolerance to 0 or 1 respectively
for i in range(len(lst)):
    starts = [lst[i][1].segments[0]['Layup'][j][0] for j in range(len(lst[i][1].segments[0]['Layup']))]
    ends = [lst[i][1].segments[0]['Layup'][j][1] for j in range(len(lst[i][1].segments[0]['Layup']))]
    min_start = min(starts)
    max_end = max(ends)
    if min_start != 0 or max_end != 1:
        print("WARNING: No closed section found in segment 0. Segment has been closed.")
        if lst[i][0]<0.6 or lst[i][0] == 1:
            tolerance = 1e-4
        else:
            tolerance = .05
        for j in range(len(lst[i][1].segments[0]['Layup'])):
            if lst[i][1].segments[0]['Layup'][j][0] <= min_start + tolerance:
                lst[i][1].segments[0]['Layup'][j][0] = 0
            if lst[i][1].segments[0]['Layup'][j][1] >= max_end - tolerance:
                lst[i][1].segments[0]['Layup'][j][1] = 1

I will work on making this fix more robust. Please let me know if this fixes the problem!

[EVElove444]

I'm sorry I didn't solve this problem. I adjusted the tolerance and the layer thickness in yaml file. But the problem still exists.

[KIDEVLIN]

I want to check that the warning message "No closed section found in segment 0. Segement has been closed" is printed. If the warning is not printed, the problem is somewhere else. If this warning message is printed, that means that the layup in the yaml file is not closed. The code block in my previous message is a temporary fix for yaml input files with unclosed layups. I suggest changing the start and end points of layers in the yaml file to close the layup. For example with the 5MW turbine, the following layers should start at 0 and 1 in the yaml file:

UV_protection:

• start_nd_arc values: 0.0, 0.0, ....
• end_nd_arc values: 1.0, 1.0, ....

TE_reinforcement_SS:

• start_nd_arc values: 0.0, 0.0, ....

TE_reinforcement_PS

• end_nd_arc values: 1.0, 1.0, ....

Let me know if this fixes the issue or if the warning message is not printed.

[EVElove444]

Hello, the error has not been resolved. The error message is as follows: Subsequently, I made adjustments to the determine_a_nodes function.

Traceback (most recent call last):
File "/home/su/Desktop/SONATA-SONATAmini/examples/6_NEW IEA_5MW/6_sonata_IEA5.py", line 66, in
job.blade_gen_section(topo_flag=True, mesh_flag = True)
File "/home/su/Desktop/SONATA-SONATAmini/SONATA/classBlade.py", line 503, in blade_gen_section
cs.cbm_gen_mesh(**kwargs)
File "/home/su/Desktop/SONATA-SONATAmini/SONATA/cbm/classCBM.py", line 290, in cbm_gen_mesh
self.mesh.extend(seg.mesh_layers(self.SegmentLst, global_minLen, self.WebLst, display=self.display, l0=self.refL))
File "/home/su/Desktop/SONATA-SONATAmini/SONATA/cbm/topo/segment.py", line 283, in mesh_layers
layer.mesh_layer(SegmentLst, global_minLen, display=display, l0=1.5 * l0)
File "/home/su/Desktop/SONATA-SONATAmini/SONATA/cbm/topo/layer.py", line 273, in mesh_layer
self.determine_a_nodes(SegmentLst, global_minLen, display)
File "/home/su/Desktop/SONATA-SONATAmini/SONATA/cbm/topo/layer.py", line 229, in determine_a_nodes
tmp_nodes = [tmp_layer.a_nodes[0]] + tmp_layer.b_nodes + [tmp_layer.a_nodes[-1]]
IndexError: list index out of range

def determine_a_nodes(self, SegmentLst, global_minLen, display=None):
    """ """
    unmeshed_ids = []
    for seg in SegmentLst:
        if seg.LayerLst:
            unmeshed_ids.append(int(seg.LayerLst[-1].ID + 1))

    new_a_nodes = []
    for iv_counter, iv in enumerate(self.inverse_ivLst):
        if int(iv[2]) in unmeshed_ids:
            eq_nodes = []
            BSplineLst = self.a_BSplineLst
            iv_BSplineLst = trim_BSplineLst(BSplineLst, iv[0], iv[1], self.S1, self.S2)
            if iv_counter == 0 and len(self.inverse_ivLst) > 1:
                IncStart = True
                IncEnd = False

            elif iv_counter == 0 and len(self.inverse_ivLst) == 1:
                IncStart = True
                IncEnd = True

            elif iv_counter == len(self.inverse_ivLst) - 1 and len(self.inverse_ivLst) > 1:
                if iv_counter == len(self.inverse_ivLst) - 1 and iv[1] == 1 and self.inverse_ivLst[0][0] == 0:
                    IncStart = False
                    IncEnd = False
                else:
                    IncStart = False
                    IncEnd = True

            else:
                IncStart = False
                IncEnd = False

            eq_nodes = equidistant_nodes_on_BSplineLst(iv_BSplineLst, True, IncStart, IncEnd, minLen=global_minLen,
                                                       LayerID=self.ID)
            new_a_nodes.extend(eq_nodes)

        else:
            print(f"Attempting to find layer with ID {iv[2]}")
            tmp_layer = get_layer(int(iv[2]), SegmentLst)
            if tmp_layer is None:
                print(f"Layer with ID {iv[2]} not found in SegmentLst.")
                continue

            print(f"Found layer with ID {tmp_layer.ID}")
            iv_BSplineLst = trim_BSplineLst(self.a_BSplineLst, iv[0], iv[1], self.S1, self.S2)
            isClosed = iv_BSplineLst[0].StartPoint().IsEqual(iv_BSplineLst[-1].EndPoint(), 1e-5)

            if isClosed:
                tmp_nodes = tmp_layer.b_nodes
            else:
                print(f"tmp_layer.a_nodes: {tmp_layer.a_nodes}")
                print(f"tmp_layer.b_nodes: {tmp_layer.b_nodes}")
                if tmp_layer.a_nodes and tmp_layer.b_nodes:
                    tmp_nodes = [tmp_layer.a_nodes[0]] + tmp_layer.b_nodes + [tmp_layer.a_nodes[-1]]
                else:
                    print(f"Layer {tmp_layer.ID} has empty nodes.")
                    continue

            print(f"tmp_nodes: {tmp_nodes}")
            disco_nodes = grab_nodes_on_BSplineLst(tmp_nodes, iv_BSplineLst)
            new_a_nodes.extend(disco_nodes)
            try:
                tmp_nodes = [tmp_layer.a_nodes[0]] + tmp_layer.b_nodes + [tmp_layer.a_nodes[-1]]
            except IndexError as e:
                print(f"IndexError: {e}")
                print(f"tmp_layer.a_nodes: {tmp_layer.a_nodes}")
                print(f"tmp_layer.b_nodes: {tmp_layer.b_nodes}")
                raise

    self.a_nodes = remove_duplicates_from_list_preserving_order(new_a_nodes)
    self.a_nodes = merge_nodes_if_too_close(self.a_nodes, self.a_BSplineLst, global_minLen, 0.01)

I also changed the thickness of the trailing edge material in the YAML file, but the generated diagram still has errors. The airfoil shapes at both ends are incorrect, although the code does not report any errors.

[KIDEVLIN]

Hi,
I don't know what is happening here. The purpose of the section of the function determine_a_nodes with the error transfers nodes from one segment to the current segment (nodes from where web segments meet the spar cap). It looks like it is trying to transfer nodes on a web that does not exist. If you send me the YAML file you are using as input, I can try to debug the issue.

[KIDEVLIN]

Hello,
I think I found the issue! The only changes between the original YAML file and your new file was updating the airfoil coordinates. Plotting the new coordinates shows that there was an overlap at the trailing edge shown in the image below. This caused SONATA to think that the pressure side of the airfoil was actually the suction side. I applied a change to check and fix this issue automatically. The fix will be pushed here but if you do not want to wait, just change the interpolate_shapes function in the classAirfoil file to:

def interpolate_shapes(self, af1, af2, t):
    """Interpolate between shape1 and shape2 based on parameter t (0 <= t <= 1)."""
    # Ensure both shapes have the same number of points
    if np.mean(af1[int(len(af1)*1/6):int(len(af1)*1/3), 1]) < 0:
        af1 = np.flip(af1,0)
    if np.mean(af2[int(len(af2)*1/6):int(len(af2)*1/3), 1]) < 0:
        af2 = np.flip(af2,0)
    num_points = max(len(af1), len(af2))
    af1 = self.normalize_points(af1, num_points)
    af2 = self.normalize_points(af2, num_points)

    # Interpolate between shapes
    interpolated_shape = (1 - t) * af1 + t * af2

    # Adjust to maintain the property that the first and last y values average to 0
    avg_y = (interpolated_shape[0, 1] + interpolated_shape[-1, 1]) / 2
    interpolated_shape[0, 1] -= avg_y
    interpolated_shape[-1, 1] -= avg_y

    return interpolated_shape

Let me know if this helps.

[KIDEVLIN]

Hello, I think I found the issue! The only changes between the original YAML file and your new file was updating the airfoil coordinates. Plotting the new coordinates shows that there was an overlap at the trailing edge shown in the image below. This caused SONATA to think that the pressure side of the airfoil was actually the suction side. I applied a change to check and fix this issue automatically. The fix will be pushed here but if you do not want to wait, just change the interpolate_shapes function in the classAirfoil file to:

def interpolate_shapes(self, af1, af2, t):
    """Interpolate between shape1 and shape2 based on parameter t (0 <= t <= 1)."""
    # Ensure both shapes have the same number of points
    if np.mean(af1[int(len(af1)*1/6):int(len(af1)*1/3), 1]) < 0:
        af1 = np.flip(af1,0)
    if np.mean(af2[int(len(af2)*1/6):int(len(af2)*1/3), 1]) < 0:
        af2 = np.flip(af2,0)
    num_points = max(len(af1), len(af2))
    af1 = self.normalize_points(af1, num_points)
    af2 = self.normalize_points(af2, num_points)

    # Interpolate between shapes
    interpolated_shape = (1 - t) * af1 + t * af2

    # Adjust to maintain the property that the first and last y values average to 0
    avg_y = (interpolated_shape[0, 1] + interpolated_shape[-1, 1]) / 2
    interpolated_shape[0, 1] -= avg_y
    interpolated_shape[-1, 1] -= avg_y

    return interpolated_shape

Let me know if this helps.

This code has been edited to allow for circular airfoil inputs.

[EVElove444]

Dear KIDEVLIN,

I hope this message finds you well. I wanted to express my sincere thanks for your assistance with the airfoil issue; it has been resolved successfully.

However, I have encountered a new problem related to the image generation part of the job.blade_plot_beam_props() command. The error code is as follows, and despite numerous attempts to modify it, I have not been able to resolve the issue.

Thank you very much for your attention to this matter.

Best regards,
RuntimeError: latex was not able to process the following string:
b'\\begin{minipage}[b]{10cm} \\underline{\\textbf{Description:}} \\\\The 6x6 sectional stiffness matrix, TS (Timoshenko Stiffness Matrix) (1-extension; 2,3-shear, 4-twist; 5,6-bending) relates the sectional axial strain, $\\epsilon_1$, transverse shearing strains, $\\epsilon_2$ and $\\epsilon_3$, twisting curvatures, $\\kappa_1$ and two bending curvatures, $\\kappa_2$ and $\\kappa_3$, to the axial force, $F_1$, transverse shear forces, $F_2$ and $F_3$, twisting moment, $M_1$, and two bending moments, $M_2$ and $M_3$. The relationship between these sectional strains and sectional stress resultants takes the form of asymmetric, 6x6 matrix: \\\\$$ \\left( \\begin{matrix} F_{1} \\\\ F_{2} \\\\ F_{3} \\\\ M_{1} \\\\ M_{2} \\\\ M_{3} \\end{matrix} \\right) = \\left( \\begin{matrix} k_{11} & k_{12} & k_{13} & k_{14} & k_{15} & k_{16} \\\\ k_{12} & k_{22} & k_{23} & k_{24} & k_{25} & k_{26} \\\\ k_{13} & k_{23} & k_{33} & k_{34} & k_{35} & k_{36} \\\\ k_{14} & k_{24} & k_{34} & k_{44} & k_{45} & k_{46} \\\\ k_{15} & k_{25} & k_{35} & k_{45} & k_{55} & k_{56} \\\\ k_{16} & k_{26} & k_{36} & k_{46} & k_{56} & k_{66} \\end{matrix} \\right) \\cdot \\left( \\begin{matrix} \\epsilon_{1} \\\\ \\epsilon_{2} \\\\ \\epsilon_{3} \\\\ \\kappa_{1} \\\\ \\kappa_{2} \\\\ \\kappa_{3} \\end{matrix} \\right) $$ \\end{minipage} '

Here is the full command invocation and its output:

latex -interaction=nonstopmode --halt-on-error --output-directory=tmpxbqmgplb 127908b223a4cf777898c60ef5e3e286.tex

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restricted \write18 enabled.
entering extended mode
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(/usr/share/texlive/texmf-dist/tex/latex/underscore/underscore.sty)
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No file 127908b223a4cf777898c60ef5e3e286.aux.
geometry driver: auto-detecting
geometry detected driver: dvips

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l.29 ...} \right) = \left( \begin{matrix} k_{11} &
k_{12} & k_{13} & k_{14} ...
No pages of output.
Transcript written on tmpxbqmgplb/127908b223a4cf777898c60ef5e3e286.log.