Week 6-Meshing of Hood Challenge

AIM:

• Extraction of mid surface of the given model
• meshing the component (bonnet of car) under the different quality criteras

SOFTWARE USED :

Hypermesh 2020

THEORY

Hood model is the component used in the car which is used to cover the engine compartment and which gives the good aerodynamic structure for the easy flow of air

It is made of steel as because to resist the high temperature which are produced in the engine compartment

The hood model which also protects the engine compartment from the environmental elements

COMPONENT AND ITS PARTS

1.OUTER HOO

2.INNER HOOD

3.LATCH (LEFT)

4.LATCH (RIGHT)

QUALITY CRITERIA

S.N	Quality Criteria	Value
1	Aspect Ratio	5
2	Skewness	45
3	Warping	15
4	Taper	0.5
5	Min. Length	2 Units
6	Max. Length	8 Units
7	Min angle Quad	45
8	Max angle Quad	135
9	Min angle Tria	20
10	Max angle Tria	120
10	Tria %	10

Procedure

1. Import: the given model is imported into the gui using the import tool the model imported is in the .stp file which is saved into the .hm format
2. Here , the imported model contains the solids which are to be deleted for the taking the midsurface

the above fig shows the model imported

3.MIDSURFACE(LATCH)

• The latch geometry is selected by selecting the latch from the utility menu
• Taken midsurface by using the automidsurface tool
• (geometry>automidsurface>select the surface>displayed>ok)
• Near the hole areas the washer element is created to reduce the stress concentration and for good uniform flow of mesh

Fig of the latch midsurface

Hinges

• same procedure is followed for the hinges for the mid surface

fig of the hinges after taking the mid surface

outer geometry(midsurface)

• midsurface for the outer extract is taken and the geometry clean up is done manually using the quick edit tool
• edge fillet

here as the radius of the geometry is less then the given target element size it is manually adjusted to achieve the given quality conditions

• middle curve :

select the outer edge curves of the fillet through out the geometry and middle curve is generated in between the fillets

(geometry>lines>middle line>select the line 1. Select line 2>ok)

• furtherly it is projected on the surface and splitted into halves

(geometry>quick edit>surface split line>select the surface >node 1> node 2>ok)

• fillet lines are now suppressed using the toggle option
• (geometry>quick edit > toggle>select the line)
• Create a separate component in which the midsurface of the outer geometry is imported
• (utility>create>component.rename>outer geometry>ok)
• (geometry>organise>import>select the surface>displayed>ok)

the above image shows the midsurface od outer extract

Inner extract

• Midsurface is taken for the inner extract auto mid surface tool

(geometry >automidsurface >select the surface by attached >ok)

• Geometry clean up:

At the fillet areas the mid surfaces intersection takes places which are deleted and created by the surfaces

(geometry>surfaces>select the surfaces>delete>ok)

• (geometry>surfaces>filler>ok)
• Create the component using the utilty bar and import using the organise
• (create>component>rename>outer layer midsurface>ok
• (geometry>organise>component>displayed>ok)

The inner extract symmetry image

Meshing

Here, the mid surface component is meshed , meshing is the process in which the whole component is divided into the equal number of elements . for the stimulation purposes

Latch(meshing)

• the latch surface is selected and mesh is applied using the automesh tool
• (surface>2d>automesh>select the surface >ok)
• Element size is targeted into 5mm the whole element is equally divided into the 5mm
• Quality criteria values are entered in the quality index
• (2d>quality index>qi settings>values to be entered>ok)

The above fig shows the latch(meshed)

The component meshed to be satisfied the given quality criteria for which the given mesh elements are edited and evaluated using the element clean up tools. While meshing the quads and trias are controlled by adjusting the number of nodes created

Remesh: the areas where the element distribution is unequal the areas are selected by the element criteria selection and remeshed

In this process the number of the trias are reduced and few of the quality failure are sorted out

the above image shows the remesh method

Node optimisation :

Few of the warpage and the minimum length quality failures are addressed by the node optimisation where the it adjust the length of the elements by evaluating the sides

place node

By using the place node clean up tool the particular element is selected and adjusted by moving the node of the element

Outer hood (meshing)

Here, the outer extract is selected and the half of the geometry meshed which is after reflected on the other half of the outer geometry

• The component is divided into the larger areas by using the surface split tool for the good mesh flow
• The component is meshed then and mesh is adjusted by using the meshing the elements repeatedtly
• Align node:

at the corners mesh flow is seen in ununiform which is sorted out on to the line by the using the align nodes

select the parent to n1 n2 as reference node and nodes which are to be aligned are selected next

(geometry>node edit>align node> select n1, n2>select the nodes to be aligned >ok)

The above image shows the application of align tool

Smooth: it is the element clean up tool which is resolves the quality failures .here , it adjusts the element dimension without the movement in the elements

The above image shows the application of smooth tool

Combine: it is also used to join the trias to form the quad elements

The above image shows the application of combine tool

Reflect the outer extract symmetry

After the element clean up the symmetry is reflected on the other half side using the reflect tool

(tools>reflect>select the elements>by displayed>duplicate>current >y axis >base point> on the geometry>reflect>return)

the above image shows the outer hood meshing image before reflecting

Reflecting the surface

(tools>reflect>select the surfaces>by displayed>duplicate>current >y axis >base point> on the geometry>reflect>return)

The above image shows the reflected outer hood image included surface

• EDGES

After meshing the elements in few are not addressed accurately which are adjusted by deleting the edges and joining the nodes

After reflecting the outer extract the edge is formed at the mid section which is to be deleted and to be whole component should be made as a whole component

Nodes are addressed in 2 ways

1. Manually by replace nodes
2. Adjusting the tolerance between the elements

BY TOLERANCE: select the elements deleted the edges and the adjusted by the equivalence

(tools>select the elements >edges>delete edges>preview equivalence>equivalence>ok)

The above fig shows the application of equivalence tool

REPLACE(MANUALLY)

The nodes are selected individually and joined

(geometry>replace>node1>node 2>ok)

The image shows the application of replace tool

Inner extract(meshing)

the inner extract component is sectioned into two halves where the one half is meshed and reflected on the other side using the reflect tool

1.toggled the small lines which are effecting the meshing

(geo>quivk edit>toggle left click>ok)

2.meshing the component by dividing into larger areas using the quick edit tool

the above image shows the inner hood after meshing and reflecting the symmetry

RESULT

The above image shows the overall image of hood model after meshing

Outcomes

1. Learnt how to take the midsurface of the given model
2. Learnt how to mesh the given model under given target element size
3. Learnt how to element clean using the element edit tools

the model link is enclosed below

https://drive.google.com/file/d/1uTFXSn8XNep7MMil9_BQzs8pIxF6n1Jr/view?usp=drive_web

https://drive.google.com/file/d/1uTFXSn8XNep7MMil9_BQzs8pIxF6n1Jr/view?usp=sharing