Draft analysis:

Deep drawing is a process where a sheet metal is formed using the process of pressing the sheet against a die using a punch. Deep drawing angle is angle between the perpendicular axis with respect to the tangent drawn with respect to the wall.

This angle decides the quality of the 3d sheet metal part. It affects the tool wear, formability, material deformation and surface finish. Deep drawing angle more or less than necessary result in wrinkling and sheet overlapping.

The deep drawing angle for the hood assembly is 9.91^o.

Draft analysis has been conducted for the inner panel of the hood assembly. The drafting angle for the inner panel should, at least be 5^o. Generally, the angle has to be 7^o or more.

The component has 7^o of draft overall. But in this figure, you can see that many embosses have less than 5^o and a few other having a negative draft angle, especially at the hinge embosses.

This is mainly due to the absence of a tooling direction. Tooling direction help the component tool the it uniformly from the die.

Section Modulus:

The section modulus tells us whether the given sheet metal will bend easily or not. It gives a measure of resistance of a cross section of a sheet metal component. It is defined as the ratio of moment of inertia to the farthest point on the section with respect to the end point.

Z = I/y

Where,

• Z = Section modulus
• I = Moment of inertia
• y = Distance of the farthest point in the section from the neutral axis

The distance of the farthest point from the normal axis (mirroring element) is 440.06 mm as shown in the figure. This will be constant in both the cases where we will be analysing the section moduli.

Case I:

When we have a small cross section area:

In the above intersection, we have a leaner cross section. It has an area of 1.03 x 10³ mm2 and a length of 3.68 x 10³ mm.

It has a maximum moment of inertia of 8.60 x 10⁷ mm⁴ and a minimum moment of inertia of 2.48 x 10⁵ mm⁴.

When it has the minimum moment of inertia, the section modulus will be:

Z = I/y

I = 2.48516 x 10⁵ mm⁴

y = 440.06 mm

Z = (2.48 x 10⁵)/440.06 = 564.809 mm³

Case II:

This section however, has a thicker cross section compared to the previous section. The section has been made thicker intentionally to calculate the section modulus and check how the increased area affects the section modulus.

It has a maximum moment of inertia of 8.5923 x 10⁷ mm⁴ and a minimum moment of inertia of 2.4851 x 10⁵ mm⁴.

When it has the minimum moment of inertia, the section modulus will be:

Z = I/y

I = 2.4621 x 10⁵ mm⁴

y = 440.06 mm

Z = (2.4621 x 10⁵)/440.06 = 560.173 mm³

Conclusion:

The bending resistance is calculated using the section modulus. Hence, larger the section modulus, higher is the bending resistance. Comparing the above results for each of the case I and case II, the section in the case I has the higher section modulus than in case II. Thus, the section with lower cross section area has the highest resistance to bending.

Difference between the section moduli: 564.809 mm³ - 560.173 mm³ = 4.63 mm³

^{Please find the report in the attachment}

^{Report = Draft and section analysis.docx}

^{Images = Images.zip}