Week 6-Meshing of Hood Challenge

INTRODUCTION :

• The Hood or Bonnet is hinged cover over the engine of motor vehicles. Hoods can open to allow access to the engine over the engine of motor compartment or trunk for maintenance repair.
• In recent years the work has been done on the bumper and hood design of the vehicle front end to reduce the injuries to the pedestriants in the events of a pedestrian vehicle collision.
• The front portion of the vehicle gets damaged when met with accident.so there is need to change the existing design of bonnet or by charging the material.
• The bonnet is hinged cover over the engine of motor vehicles that allows access to the engine compartment for maintenance and repair
• Bonnet usually do not directly open onto the passenger cell which greatly reduces the importance closures such as air tightness, passenger safety , low cycle fatigue strength etc.
• The objective of these measures is to reduce the number of road accident fatalities and the severity of injuries sustained by pedestrian involved in a collision with a vehicle in urban traffic.
• Impact frequency and seriousness of injury has been studied for many years, resulting in rating system and improved design.
• The bonnet system is an access panel to the engine compartment to enable maintenance of power train , drive belts , battery , fluid levels and lamp units. it is fundamently a reinforced skin panel with many safety and quality requirements.

AIM :

• To extract Mid surface and generate mesh on Hood using Hyper mesh

MESHING OF HOOD:

• Here we will see the meshing of different parts of hood.
• Hood consist of four different components as below

1. Inner extract
2. Outer extract
3. Hinge reinforcement extract
4. Latch reinforcement extract

QUALITY CRITERIA :

• Quality criteria for the meshing of all the components are given as below
• Target Element Length : 5 Units

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 :

Now we will see all the components one by one

INNER EXTRACT :

• There are four different components in the file when we import it.
• First of all make sure that only " Inner extract "component is active.
• Delete all solids from the component.
• Create mid surface for only inner extract by selecting particular surfaces.
• Since this component is axis symmetric , we can cut it in to half and mesh it.

• As shown in above image , split the mid surface and keep half of that for meshing.
• Start Meshing with the closed area with less free edges.
• And avoid washer surfaces if possible
• Keep the mesh flow as per geometry and create mesh with less tria elements

• Complete the mesh of the half portion of the inner extract as shown in above image.
• Now we can reflect the elements on the other side and complete the total mesh on the component.

• As shown in above image , elements are reflected on the other side.
• Make sure that elements are in proper connectivity.
• So, create equivalence between the elements which are in symmetric line and make them connected as shown in above image.
• Thus we can complete the meshing process for "Inner Extract " component.

OUTER EXTRACT :

• Here we can see the component is axis symmetric , so we can cut it into half.

• Create midsurface after deleting solids from outer extracts as shown in below image.

• As shown in above image , the hemming portion of the component is very thin
• So, After creating mid surface , we can toggle the extra edges and split the component from the curvature area as shown below image and easily create mesh without minimum length element.

• Start with the curved or radius portion to avoid minimum length elements and step create mesh as shown in below image.
• We can futher divide the curved portion marked in below image and create better quality elements in that region
• Refect the mesh and create equivalance in the symmetry region.

• Thus we can complete the Mesh of " Outer Extract " component with better mesh flow.

LATCH REINFORCEMENT EXTRACT :

• Delete solids and create mid surface for Latch Reinforcement extract component.
• Do necessary cleanup and toggle extra edges.

• Remove edge fillet from marked portion for better mesh quality.
• As shown in above image, create washer surface with 5mm distance and split the surface for better mesh structure.

• Keep the mesh flow as per the geometry.Avoid tria elements at the free edges.
• As shown in above image, create mesh at the centre first and then proceed further for good mesh and complete the entire mesh for Latch Reinforcement extract.

HINGE REINFORCEMENT EXTRACT :

• Here there are two components in Hinge Reinforcement extract.
• If we create mesh only for one, we can reflect it on other.
• So, delete solids and create mid surface for one part , we can reflect it on other.
• So,delete the solids and create mid surface for only one part.
• As shown in above image , avoid creating washer surface for the holes for better mesh arrangement.
• Toggle the edges where minimum length element can occur.

• As shown in above image, mesh is created at the inner most area where less free edges are there.
• Then followed by them, rest of the part is meshed.
• After creation of mesh on one part, with reflect option, mesh is reflected on the other parts as well.
• Thus we can mesh on both the parts of hinge reinforcement extract.

MESH RESULT :

INNER EXTACT:

OUTER EXTRACT :

LATCH REINFORCEMENT EXTRACT :

HINGE REINFORCEMENT EXTACT :

THICKNESS :

• After meshing all the components , apply 2 units thickness to all.
• After applying thickness , complete meshed Hood will look as shown in above image.

CONCLUSION :

For the given hood panel mid surface is extracted and mesh is generated with the given quality criteria.

File Link : https://drive.google.com/file/d/19ri0-oN1KmqrYjKjtbb2nTXCPco4AbhV/view?usp=sharing