SDT-visc         Contents     Functions              PDF Index

3.3  Composite blade meshing tutorial

• Initial data
• Initial mesh generation

3.3.1  Initial data

The objective of this section is to illustrate strategy proposed to mesh a composite blade possibly containing viscoelastic patches. One starts from

• area a mid-plane surface mesh defining ply areas. This may be modified to include viscoelastic patch boundaries. In the present example, level set cuts were used to define lines associated with target thickness and fe_gmsh was called to generate a surface mesh.
• skin a surface that will be used to define the outer volume of the blade. This surface does not initially contain upper/lower splitting, so this is performed in step SplitSkin xxxGV have some documentation xxxlinks
• insert a surface defining the internal part placed between the upper and lower faces of the blade during the ply placement before RTM injection.

sdtweb d_mesh  NacaSkin % see also meshing steps that were used

xxx the ability to use lsutil to generate cuts at target thickness.

---

Figure 3.2: Left : initial box mesh and with fixed thickness cuts. Right : area mesh (green and blue) following the target thickness boundaries, partial view of skin mesh (yellow, orange) xxxGV named colors proid/name/color / d_visco nmap colors sdtweb _mtag map:matname xxx

---

%% Step init : possibly reload 
% keywords{var{},fcn{sdtu.f.safe,sdtu.logger.status,sdth.sfield}}
f1=sdtu.f.safe('@tempdir/sdtdemos/d_visco_compPly.mat');
sdtu.logger.status('CmdDisp','on');% Turn logViewer on
if exist(f1,'file')
 load(f1,'RA');RA=sdth.sfield('rename;',RA,{'nmap','projM'});
end

if 1==2
    sdtweb t_4sheet docstring
   sdtu.logger.status('CmdDisp','on');
   d_visco keywords
   sdtweb _taglist sdtu.f % Generate idx and thus DocString graphs
end

3.3.2  Initial mesh generation

%% Step mesh : initial mesh generation 
% keywords{var{plyList,MacroLayer,PrePl},fcn{sdtu.fe.boxMacroPly}}

f1=sdtu.f.safe('@tempdir/sdtdemos/d_visco_compPly.mat');
sdtu.logger.status('CmdDisp','on');% Turn logViewer on
if exist(f1,'file')
 load(f1,'RA');RA=sdth.sfield('rename;',RA,{'nmap','projM'});
else;
 RA=d_mesh('nmap.Naca');
 RA.nmap('CurExp')={'MeshCfg{d_mesh(Naca{HyFoilA,zs.1,yn1,unitmm}):empty}','RunCfg{feplot(2)}'};
 sdtm.range.RA); RA=sdth.sfield('rename;',RA,{'nmap','projM'});
 remove(RA.projM,'cf');sdtm.store.f1,'RA>RA')
end

% Define names for each area
mo3=RA.projM('area');if ~isfield(mo3,'nmap');mo3.nmap=vhandle.nmap;end
proM=mo3.nmap('Map:SetName');proM.append({'Pro:1','A1';'Pro:2','A2';'Pro:3','A3'})

% Define the FootStart line as a set in area for later extension
mo3=feutil('addset NodeId',mo3,'FootStart','linetopo{starts 1 32,cos .9}');

RA.projM('PlyDef')=struct( ...
'plyList', ... % define ply list 
  {{'PlyNum','PlyMat','Thick','Orient','sel'
     1,  'X', 0.5, 0,'ProName"(A1|A2|A3)"'
     2,  'U', 1,   0,'ProName"(A1|A2|A3)"'
     3,  'U', 1,  90,'ProName"(A2|A3)"'
     4,  'Y', Inf,   0,'ProName"(A2|A3)"'
     5,  'U', 1,  90,'ProName"(A2|A3)"'
     6,  'U', 1,   0,'ProName"(A1|A2|A3)"'
     7,  'X', 0.5, 0,'ProName"(A1|A2|A3)"'
     }},...
 'MacroLayer', ...  % define macro layers 
    {{'Name','MacroPly','Plies', 'Area','ProIdOut'; 
     'A1Top', 1,        [  1 2], 'A1',1001;
     'A2Top', 1,        [1 2 3], '(A2|A3)',[1002 1003];
     'Insert',2,             4 , 'A3',     2003
     'Fill',  2,             4 , '(A1|A2)',[2001 2002]
     'A1Bot',3,           [6 7], 'A1',   3001;
     'A2Bot', 3,        [5 6 7], '(A2|A3)',[3002 3003]
     }}, ...
'PrePl', ... % define ply materials
  {{'name','X','U','Y';
   'MatId',30,31,32;
   'color','Coral','OrangeRed','DarkOrange';
   'E1',60e3,30e3,14e3;
   'E2',4e3,30e3,14e3;
   'E3',4e3,9e3,7e3;
   'nu12',.3,0.04,0.3;
   'nu13',.3,0.4,0.3;
   'nu23',0.488,0.4,0.35;
   'G12',2e3,2e3,5e3;
   'G13',2e3,2e3,2e3;
   'G23',2e3,2e3,2e3;
   'Rho',1400e-9,1400e-9,1500e-9}});

mo3=sdtu.fe.boxMacroPly(mo3,RA.projM('PlyDef'));mo3.name='area';
RA.projM(mo3.name)=mo3; 
fevisco('MeshPliesViewH',mo3) % 'xxx document error on thickness on layer edges'

if sdtweb('_TutoNeed','figgen')
 cf=feplot(2,';');cf.mdl=RA.projM('area');fecom showfipro
 comgui('imwrite',2,'@tempdir/sdtdemos/plots/d_visco_TutoCompPly_StepMesh.png')
 sdtu.ui.tabChange('SDT Root.Tab.PlyList');gf=gcf;
 cingui('objset',gf,{'Position',[NaN NaN 592 236]})
 comgui('imwrite',gcf,struct('Java',5,'FileName','@tempdir/sdtdemos/plots/d_visco_TutoCompPly_TabPlyList.png'))
 sdtu.ui.tabChange('SDT Root.Tab.PlyList');gf=gcf;
 comgui('imwrite',gcf,struct('Java',5,'FileName','@tempdir/sdtdemos/plots/d_visco_TutoCompPly_TabMacroLayer.png'))
 ta=sdtu.ui.tabChange('SDT Root.Tab.PlyList');ta=ta.Source;
 ta.param.colM.prop('PlyNum').fmt='%i';
 ta.param.colM.prop('Thick').fmt='%.1f';
 asTex(ta)
end
if sdtweb('_TutoNeed','check')
 % if ~isequal()  sdtm.Hash('reproducible',) 
end

mesh

The plyList table gives the relation between ply numbers, the associated material PlyMat, thickness, material orientation with respect to the local x_e,y_e plane, and selection (see findElt ) of area whose elements are covered by a given ply. The inf in the Y layer indicates that its thickness is variable the insert in this case.

To allow the automated definition of macro plies (volume element combining multiple plies), the MaCroLayer table then gives the name of macro areas, the index of each macro ply, the plies associated with a selected area, and the property number associated with

Finally, the PrePl table gives elastic properties of plies as shown below. This is then used to define an orthotropic material for each macro ply using KUBC homogeneisation [48].

xxx texSafeCell

d_visco('TutoCompPly -s{Mesh,SplitSkin} -show -reset -need{figgen,check};') xxxgv/gm revise two icons to run/open code.

Step boxInSkin then projects the area onto the surface. This generates a topological box where there is one hexa8 element through the thickness. Topological box meshes can be used for surfaces quad4 or volumes hexa8.

• 0em .EdgeN contains through thickness edges (posts) three columns are BottomId, TopId, Thick. The position of top and bottom surfaces is obtained using lsutil.html#dToSurf on the skin (which must be split into a top and bottom surface, here using lsutil.hmtl#cut ). feutilb.html#MeasThick is a related command.
• sdtu.fe.boxPlanes(model,.75) meshes a surface if only r=0.75 value. When giving a matrix of r, one can mesh multiple layers. Degenerate elements can be eliminated using mo2=fe_quality( 'cleandegenrecast;',mo2);.
• When, meshing layers the areas are affected the NewProId=OrigProId+1000*Layer. It is then possible to reaffect these to target numbers using .MatIdOut.
• Generate normal field associated with this surface (xxxEB issues interpolation of normals in curved areas, MakeSandwich Nodes/elt)

MeshLayerV2

---

Figure 3.3: Left : initial box, center : layer meshes with insert in green, fill in yellow and top layer in xxxGV revise assignation of colors Map:ProColor . Right : horizontal and vertical cuts of the mesh.

---

Step RSZMap defines distance maps that will later be used for foot meshing.

• 0em .TopFootR defines an r coordinate on the top skin (model skin, matid 101) using distance to the orientation line z>50.

  struct('distFcn','fe_shapeoptim','model','skin', ...
  'SurfSel','matid 101','OrientLine','z>50');

• .BotFootR does the same for the bottom skin surface.
• .BladeS uses the distance to a plane defined using the simple quadrangle stored in BladeSSurf struct('distFcn','lsutil','model','BladeSSurf', ...
  'useZe',1,'sel','matid103');
• ThickBot defines a distance to bottom of skin.
• ThickTop defines a distance to top of skin.
• ThickArea defines a distance to area plane (about middle)

---

Figure 3.4: Definition of coordinate maps

---

Step MeshRS extends the .area='MacroVol' on the skin with distance maps .skin='RSZMap' xxx 'RSZMap'. An extension is built by giving the following parameters

• name name of extention
• rCoor, sCoor, tCoor distance functions defined on the skin
• AreaEdge node numbers of xxx
• SkinEdge nodes (7 columns) corresponding to the line
• SkinFace selection of skin elements to be used for the extension
• SkinFlip -1 to change surface normal, 1 to keep it.

---

Figure 3.5: Extended mesh with foot defined

---

xxx

As the ply definition area does not go to the foot (the skin in figure 3.2 larger), a transition is needed.

To achieve this mesh while following the skin with controlled thickness, one uses a geometric mapping. An r coordinate is set at zero using

StepArea illustrates the ability to use a contour to locally remesh a patch. To allow thickness transitions, the boundary between interior and exterior is meshed using quads. StepOrientArea illustrates the ability to define material orientations, which is needed for composites

A1L1 : edge only one multiply layup

A2L1 : lower face A2L2 : core A2L3 : upper face

A3L1 : lower face A3L2 : core A3L3 : between core and visco A3L4 : visco A3L5 : between visco and upper face

xxxEB Step FootTransition

xxxEB Step OrientSensitivity : xxx sensitivity to material orientation xxx