Hood design-Week 2

Hood Design:

1. Creation of the inner panel neutral surface.

We are given the class A surface of the outer panel. Now to make the base surface for the inner panel we will first offset it bu 2 mm to make the outermost flange of the inner panel.

Given class A surface:

Using the data given in the master section we need to make the base surface of the hood inner panel. We will be making this surface by using emboses.

After making the first flange we again offset the given surface by 4 mm and then create the second flagne using the master section data, for the third and final depression in the inner panel we offset the given surface by 25 mm and give it the desired shape. This step ensures that we have adhered to the master section requirements.

Cutting of slots:

Slots are supposed to be cut into the inner panel of the hood so as to discipate the energy during a crash. These slots change the direction of the energy from directly entering the cabin and transfet it to the hinges the hood is mounted on. The slots cut into the inner panel of the hood also help in weight reduction of the component.

For cutting the slots we first need to make one large emboss while having tolerence for the latch and hinges:

Post making this large emboss we sketch shapes on this emboss in such a way that they direct the energy away from the centerline incase of a crash.

We now split the main surface with these shapes and then use sweep with draft direction to create multiple embosses. We then close these shapes.

Now we cut out the center part of these shapes while keeping points for mastic.

Hemming:

Hemming process is used to connect 2 sheet metal parts without welding. This is done on the mood to protect the class A surface of the hood from burn marks due to spot welding process which is used on other parts of the car. The outer panel of the hood is made slightly larger than the inner panel this outer panel flange is then folded around inner panel. This is done by running the outer panel trough a set of rollers and sequentialy bending it.

Now after hemming is perfmed we will work on the hinge and latch section. Make embosses for latch and provide the holes. Symmetry the hood and also the hinge and get the hinge axis.

Now make a circle keeping the mid point of the hinge axis as the origin and position the latch such that the u clamp is tangent to the circle.

Please find the CATProduct file and CATpart files attached in the zipped folder.