Hood design-Week 2

Aim: To design hood outer and inner panel, position the striker and hinges and providing emboss and mastic points.

Design considerations:

1. Outer panel thickness=0.75mm

2. Inner pannel thickness=0.75mm

3. Reniforce thickness=1.5mm

4. Minimum fillet radius=3+0.75=3.75mm

5. Providing reliefs at corners to reduce stress concentration

Functional and safety requirements:

1. The important criteria to be considered is during frontal collision, the hood should be designed is such a way that the crash be dissipated evenly in the outwaed direction towards the hinge, so that passenger safety is ensured.

2.The functional aspect of the hood is the hood opening and closing angle, to do that we tentatively place the hings and draw an axis which passes through the hinge points. Then we talk the center point(obtained from the two hinge points) and draw a circle which passes through the latch center. the circle down should be locally perpendicular to the latch to ensure proper closing of hood.

Procedure:

1.Creating the hood inner panel using the master section as shown below.

2.Creating embosses so as to dissipate the crash force towards the hing.

3.Placing the hing and striker by providing approprite embosses.

4.Providing mastic points for applying mastic which are rubber like material, which when heated spread evenly and help in reducing noise, vibration and hardness. The mastics have influence area of 80mm diameter. The mastics have influence area of 80mm is shown below(red circles).

5.Development of hood outer flange by hemming and maintaining the gap as per master sections.

Hemming:

Hemming is the process of joining inner and outer panel together. A set of rollers roll the sheet with inner panel 3-4 times to get the desired results. The gap is then filled with sealants to make joint waterproof.

6. Providing reliefs at corners to reduce stress concentration.

Conclusion:

Thus, the hood design is completed considering all the master sections and all other requirements.