Hood design-Week 2

Aim : 1.Design Hood outer panel, inner panel and the necessary reinforcements by following the Master section mentioned with the design parameter  2.Submit an assembly of Hood inner panel, outer panel, latch, hinge and the reinforcements. 3.A detailed report about the Hood Design which includes a detailed explanation…

 

Aim :

1.Design Hood outer panel, inner panel and the necessary reinforcements by following the Master section mentioned with the design parameter 

2.Submit an assembly of Hood inner panel, outer panel, latch, hinge and the reinforcements.

3.A detailed report about the Hood Design which includes a detailed explanation about hood and its components, Latch trajectory, Mastic data, Emboss definitions, manufacturing process like deep drawing and hemming, and all the parameters followed in the design.

4.The report should be well-formatted and should have a good flow of content. Add all the relevant images.

 

Solution :

First we will discuss about the use of hood :

The hood (North American English) or bonnet (Commonwealth English) is the hinged cover over the engine of motor vehicles. Hoods can open to allow access to the engine compartment, or trunk (boot in Commonwealth English) on rear-engine and some mid-engine vehicles) for maintenance and repair.

Hood Angle :

One of design parameter for design of hood is opening angle. This opening angle is being control by supporting rod or gas stay. The length of supporting rod controls the opening angle of hood. Supporting rod is placed on engine and after opening is attached to hood or vice versa.

 

 

Parts of  a Hood Assembly :

1.Support Rod :

 The support rod is used to hold the hood at the hood opening angle and is usually hinged at the engine as shown above.The support rod is usually given a curvature so that it gets strength and the curvature should be less than 35 mm as too much curvature can lead to bending .

2.GAS STAY:

It is also a Hood stay but it is automated or need some slight amount of force then gas itself actuates it and make it work desirably. Advantages: It is automatic in nature

3.Reinforcements

We give reinforcements in the area wherever there is an attachment given such as striker or hinger so that the strength in these areas increase.

 

4.Wrap Around Distance Concept :

WAD (Wrap-Around Distance) is the geometrically traced distance from the contact point with the Ground Reference Plane, vertically below the front face of the bumper, to any point on the vehicle front structure.

The wrap around distance tells us where exactly the child or adult will end uo colliding on the hood .The distance for child and adult vary according to the euro norms and should be kept in mind while designing the hood .The following pictures gives us a good example :

Now we will talk about hemming process used  :

Hemming Process :

Hemming is a sheet metal forming process in which sheets are joined by bending it usually to 180°. Automotive body panels and automotive parts such as deck-lids, trunk-lids, doors, hoods and tailgates are formed by hemming process.

 Hemming is a forming operation in which the edges of the sheet are folded or folded over another part in order to achieve a tight fit. Normally hemming operations are used to connect parts together, to improve the appearance of a part and to reinforce part edges.

Deep Drawing :

Deep drawing is a process in sheet metal forming by the mechanical action of a punch. A flat sheet metal blank is formed over a single, rigid, shape defning tool half by a flexible rubber diaphragm under uniform hydrostatic pressure.

We have the following condition :

 

 

The following class A  surface has been given to us :

We will also create assembly file as shown below :

Now we have added the part as shown below :

Now we will extract the body from the hood outer panel as shown :

We will copy this into the inner hood panel :

Now we have copied the parent class A surface and inserted into a separate part , we will use this copied surface to extract the class b and class c surface , first we will trim it about y place as it is symmetrical as shown below :

 We get the following :

We will name this working surface.

Now we will offset this surface by 2 mm :

Now we will offset the curves present on the edges of the offset surface :

Now we will use trim command as shown below :

We get the following :

Now we will get the following with respect to the working surface :

Now we will create the second flange by offsetting the working surface by 4 mm a shown below :

Now we will offset the curve on the face by 40 mm as shown below :

Now we are going to trim this sheet using the curve and keep the inner area as shown :

After this we get :

Using through curves we will connect these two surfaces as shown :

After this we get :

Now we create the final surface which is at an offset of 25 mm from the working surface as shown below:

Now we will offset the inner curve 55 mm as shown below :

We will trim the sheet and keep the inner region as shown below :

Using law extension we get the following :

We have given a draft of 5 degrees so that it can be removed easily while moulding.

Now we will be giving a face blend between the following faces :

After giving  face blend we get the following :

 

 Now we will work on the embosses for the inner region as shown below :

 

 The inner curve will be offset by 15 mm as shown below :

 Now we will use embossment command for this inner curve as shown below :

 

Now we will create another emboss as shown below :

Embossment of the hinge 

We will create a flat embossment for the attachment of the hinge assembly and we will move the hinge close to the inner panel as shown below :

After moving it we get the following :

Now in order to mount the hinge we will create an plane parallel to xz plane and close to the inner panel and create embossment which will result in flat surface , this is done because the inner panel is curved and cannot be used for attachment as it result in gaps between the hinge hole and inner panel.

Now we have created the datum plane as shown below at an offset :

We have inclined the plane as shown below :

Now we will create a sketch as shown below :

We have created the emboss and made the end cap flat as shown below :

We have mirrored the hinge as shown below :

Now we will create the hinge axis as shown below :

We have mirrored the geometry as shown below :

FINAL RESULT

We have created a circle through the center point which will helps us to find the location of the striker:

 

 

We have created a tangent as shown below :

   

 

FINAL RESULT

 

 Conclusion 

Hence we have created the hood as per design rules as shown below :