EXTRACTION OF MID AND 2D MESHING FOR THE GIVEN COMPONENTS  USING RADIOSS

                                                     

AIM: To Extract mid surface, geometry clean up and create the two dimensional mesh for the given models according to the given quality criteria by using HYPERMESH

1. MODEL 1: Practice

2. MODEL 2: Clip Repair 

3. MODEL 3: Mounting Bracket

PROCEDURE:

• Import file to hyper Mesh
• Delete solid surfaces
• Geometry clean-up
• Mid surface extraction
• Toggling lines
• Assign quality criteria
• Meshing
• Check for free edges 
• Assign thickness

MODEL 1: PRACTICE

IMPORT GEOMETRY FILE TO HYPERMESH

Import the Geometry file to hyper mesh 

For open 

Go to File >> Import >> Select geometry >> Open the model >> Click the model >> Import 

Select USER PROFILE as RADIOSS

                                                                      IMPORTING MODEL

                                                                         MODEL IMPORTED

DELETING SOLID FACES 

We only have to work on the geometry, so before inspection check for solids and delete if there are any.

Delete [F2] >> Solids >> Select by box selection >> Delete Entity

Another way to check for solids is by switching the view from AUTO MODE to TOPO MODE.

If the model is highlighted in GREEN that means solid is present.

From the image below, we can confirm that there are no solids present in the model

 

                                                      CHANGING GEOMETRY COLOUR MODE

GEOMETRY CLEAN UP

Once the model is imported move to geometry clean up just to check whether there any extra surface or free edges or missing surface will present or not

Check for errors

To check an error 

Go to visualize panel >> Disable shared edges and all except free edges

After changing geometry colour mode from AUTO to TOPO mode we can able to see the geometrical errors                        

                                                                      FREE EDGE ERROR

To fix this error we have to toggle those lines 

For that

Go to >> Quick edit command >> Toggle >> ok   

                                                                      QUICK EDIT PANEL

                                                                           TOGGLED LINE

We also see the duplicate surface present in the geometry 

To fix this 

Go to Delete (F2) >> Select the duplicate >> Delete

                                                                    DUPLICATE SURFACES

                                                                             DELETE TAB

 

                                                           DUPLICATE SURFACE DELETED

Check for other error by swtiching to wire frame mode 

Now the model is error free as shown in below fig

                                                                 WIRE FRAME MODE

MID SURFACE EXTRACTION

Once the model is geometric error free then move to mid surface

Now create a mid-surface for a given components 

Go to Geometry >> Mid surface >> Auto mid surafce >> Extraction : Skin offset >> Select the surf >> Extract 

                                                                    MID SURAFCE TAB

                                                                   SELECTING SURFACE 

                                                                             MID SURAFCE EXTRACTED

TOGGLING OF LINES

We have to make sure that the length of any line or distance between any points is above the Minimum length

 

                                                           TOGGLINING OF LINES

The fastest option for this fix is the toggle edge which is a tool under quick Edit [F11]

Quick Edit > Toggle Edge > Left click to Toggle 

                                                                   QUICK EDIT PANEL

                                                                      TOGGLED LINES

For proper feature capturing creating a mid line as shown in below fig

Go to Lines >> Mid line >> Select 1st line >> Select 2nd line >> Create

                                                   SELECTING LINES TO CREATE MID LINE

After creating a mid line we have to trim that line for that

Go to surface edit >> Trim with lines >> Select surf >> Select line >> Surface normal >> Trim

                                                               SELECTING SURFACE

                                                                SURFACE EDIT TAB

                                                                              TRIMED LINE

ASSIGN QUALITY CRITERIA

Assign quality criteria for a given model

Go to preferences >> criteria file setting >> Enter the values >> Apply >> Ok

MESHING

Mesh the given components with a given quality criteria 

Rules of mesh :

For better mesh flow we need to fallow some rules :

• Opposite tria's are avoided.
• Flat surface trai's should be avoided by merging them using split.
• Avoid trai's near to hole region.
• Hole feature should be in even numbered.
• Avoid tria's at the perimeter line.
• Avoid zig-zag mesh flow.
• Avoid rotating quads.
• Divides the large surface into small parts using split for meshing.
• Defeature the area which are going to fail the quality criteria.

Now mesh the component

Go to geometry page >> Select 2D >> Select auto mesh >> Select surface >> Create

                                                                     AUTO MESH TAB

                                                                         MESHED MODEL

CHECK FOR FREE EDGE

we have to check for free edges (red lines) in the component.

Edges Tool will help us find this error:

Tool > Edges [Shift + F3] > Elem's > Select by box slection > Find edges

                                                        CHECK FREE EDGE TAB

                                           NO DISCONNECTIVITY BETWEEN ELEMENTS ARE PRESENT

If free edges are present, connectivity won't be established between the surfaces.

As a result, when force is applied on any surface it won't be distributed to the neighbouring surface due to connectivity issue

Here in this model we don't have any free edge between the elements.

CHECK FOR NORMALS

After meshed the model check for vector normal 

To check

Go to Tool >> Normal >> Select elements display 

                                                                        NORMALS

ASSIGNING THICKNESS

The given component having thickness we can see in parent geometry 

Here we took mid surface and meshed the components so we have to assign the thickness according to parent geometry

To assign thickness 

Go to tool bar >> Create property for different thickness >> Enter thickness value 

           ASSIGNING THICKNESS VALUE

                                                ASSINGED PROPERTY TO THE COMPONENT

 

MODEL 2: CLIP REPAIR

IMPORT GEOMETRY FILE TO HYPERMESH

Import the Geometry file to hyper mesh 

For open 

Go to File >> Import >> Select geometry >> Open the model >> Click the model >> Import 

Select USER PROFILE as RADIOSS

                                                              IMPORTING MODEL

                                                                          MODEL IMPORTED

DELETING SOLID FACES 

We only have to work on the geometry, so before inspection check for solids and delete if there are any.

Delete [F2] >> Solids >> Select by box selection >> Delete Entity

Another way to check for solids is by switching the view from AUTO MODE to TOPO MODE.

If the model is highlighted in GREEN that means solid is present.

From the image below, we can confirm that there are no solids present in the model

                                                    CHANGING GEOMETRY COLOUR MODE

GEOMETRY CLEAN UP

Once the model is imported move to geometry clean up just to check whether there any extra surface or free edges or missing surface will present or not

Check for errors

To check an error 

Go to visualize panel >> Disable shared edges and all except free edges

After changing geometry colour mode from AUTO to TOPO mode we can able to see the geometrical errors   

                                            WIRE FRAME MODE TO CHECK AN ERRORS

As we seen the above fig 

Their are no error or missing surfaces present in the given geometry

MID SURFACE EXTRACTION

Once the model is geometric error free then move to mid surface

Now create a mid-surface for a given components 

Go to Geometry >> Mid surface >> Auto mid surafce >> Extraction : Skin offset >> Select the surf >> Extract 

                                                                  MID SURAFCE TAB

                                                               SELECTING SURAFCE

                                                          MID SURFACE GENERATED

GEOMETRY CLEAN UP AFTER TAKING MID:

Ignore holes which is less than dia 5mm.

For that 

Go to Quick edit >> Unsplit Surf >> ok

                                                              QUICK EDIT PANEL

 

                                   UNSPLITED DIA LESS THAN 5mm

ASSIGN QUALITY CRITERIA

Assign quality criteria for a given model

Go to preferences >> criteria file setting >> Enter the values >> Apply >> Ok

                                                    ENETRING QUALITY CRITERIA 

                                

MESHING

Mesh the given components with a given quality criteria 

Rules of mesh :

For better mesh flow we need to fallow some rules :

• Opposite tria's are avoided.
• Flat surface trai's should be avoided by merging them using split.
• Avoid trai's near to hole region.
• Hole feature should be in even numbered.
• Avoid tria's at the perimeter line.
• Avoid zig-zag mesh flow.
• Avoid rotating quads.
• Divides the large surface into small parts using split for meshing.
• Defeature the area which are going to fail the quality criteria.

Now mesh the component

Go to geometry page >> Select 2D >> Select auto mesh >> Select surface >> Create

                                                                         2D TAB

                                                                      AUTOMESH TAB

                                                                     FINAL MESHED MODEL

CHECK FOR FREE EDGE

we have to check for free edges (red lines) in the component.

Edges Tool will help us find this error:

Tool > Edges [Shift + F3] > Elem's > Select by box slection > Find edges

                                                 CHECK FOR FREE EDGE TAB

                                         NO DISCONNECTIVITY BETWEEN ELEMENTS ARE PRESENT

If free edges are present, connectivity won't be established between the surfaces.

As a result, when force is applied on any surface it won't be distributed to the neighbouring surface due to connectivity issue

Here in this model we don't have any free edge between the elements.

CHECK FOR NORMALS

After meshed the model check for vector normal 

To check

Go to Tool >> Normal >> Select elements display 

                                                                        NORMALS

ASSIGNING THICKNESS

The given component having thickness we can see in parent geometry 

Here we took mid surface and meshed the components so we have to assign the thickness according to parent geometry

To assign thickness 

Go to tool bar >> Create property for different thickness >> Enter thickness value 

                ASSIGNING THICKNESS

                                         ASSINGED PROPERTY TO THE COMPONENT

MODEL 3: MOUNTIG BRACKET

IMPORT GEOMETRY FILE TO HYPERMESH

Import the Geometry file to hyper mesh 

For open 

Go to File >> Import >> Select geometry >> Open the model >> Click the model >> Import 

Select USER PROFILE as RADIOSS

                                                                      IMPORTING MODEL

                                                                          MODEL IMPORTED

DELETING SOLID FACES 

We only have to work on the geometry, so before inspection check for solids and delete if there are any.

Delete [F2] >> Solids >> Select by box selection >> Delete Entity

Another way to check for solids is by switching the view from AUTO MODE to TOPO MODE.

If the model is highlighted in GREEN that means solid is present.

From the image below, we can confirm that there are no solids present in the model

                                                    CHANGING GEOMETRY COLOUR MODE

GEOMETRY CLEAN UP

Once the model is imported move to geometry clean up just to check whether there any extra surface or free edges or missing surface will present or not

Check for errors

To check an error 

Go to visualize panel >> Disable shared edges and all except free edges

After changing geometry colour mode from AUTO to TOPO mode we can able to see the geometrical errors   

                                                                      WIRE FRAME MODE

As we seen the above fig 

Their are no error or missing surfaces present in the given geometry

MID SURFACE EXTRACTION

Once the model is geometric error free then move to mid surface

Now create a mid-surface for a given components 

Go to Geometry >> Mid surface >> Auto mid surafce >> Extraction : Skin offset >> Select the surf >> Extract

                                                                      MID SURFACE TAB

                                                                     MID SURFACE CREATED

MID SURFACE GEOMETRY CLEAN UP:

Ignore holes which is less than dia 5mm

 

For that 

Go to Quick edit >> Unsplit Surf >> ok

 

                                                       UNSPLITED DIA LESS THAN 5mm

TOGGLING OF LINES

We have to make sure that the length of any line or distance between any points is above the Minimum length

                                                                          QUICK EDIT PANEL

The fastest option for this fix is the toggle edge which is a tool under quick Edit [F11]

Quick Edit > Toggle Edge > Left click to Toggle

                                                                       TOGGLED LINES

ASSIGN QUALITY CRITERIA

Assign quality criteria for a given model

Go to preferences >> criteria file setting >> Enter the values >> Apply >> Ok

MESHING

Mesh the given components with a given quality criteria 

Rules of mesh :

For better mesh flow we need to fallow some rules :

• Opposite tria's are avoided.
• Flat surface trai's should be avoided by merging them using split.
• Avoid trai's near to hole region.
• Hole feature should be in even numbered.
• Avoid tria's at the perimeter line.
• Avoid zig-zag mesh flow.
• Avoid rotating quads.
• Divides the large surface into small parts using split for meshing.
• Defeature the area which are going to fail the quality criteria.

Now mesh the component

Go to geometry page >> Select 2D >> Select auto mesh >> Select surface >> Create

                                                                                2D TAB

                                                                           AUTO MESH TAB

                                                                     FINAL MESHED MODEL

CHECK FOR FREE EDGE

we have to check for free edges (red lines) in the component.

Edges Tool will help us find this error:

Tool > Edges [Shift + F3] > Elem's > Select by box slection > Find edges

                                                               CHECK FOR FREE EDGE

                                                NO DISCONNECTIVITY BETWEEN ELEMENTS ARE PRESENT

If free edges are present, connectivity won't be established between the surfaces.

As a result, when force is applied on any surface it won't be distributed to the neighbouring surface due to connectivity issue

Here in this model we don't have any free edge between the elements.

CHECK FOR NORMALS

After meshed the model check for vector normal 

To check

Go to Tool >> Normal >> Select elements display 

                                                                          NORMALS

ASSIGNING THICKNESS

The given component having thickness we can see in parent geometry 

Here we took mid surface and meshed the components so we have to assign the thickness according to parent geometry

To assign thickness 

Go to tool bar >> Create property for different thickness >> Enter thickness value 

                   ASSINGING THICKNESS 

 

RESULTS: All parts are successfully meshed as per the given quality criteria and Switch to 2d detailed element representation as shown in fig below

                                                                    PRACTICE MODEL

                                                                   CLIP REPAIR MODEL

                                                                MOUNTING BRACKET MODEL

CONCLUSION:

I would like to conclude that here I learned how to take mid surafce by skin offset and how to fixed geometrical errors by using surface edit command and how to mesh for a given commponents with zero quality error.