Roof Design

ROOF CHALLENGE

Roof is the upper portion of the vehicle it help the cover the passenger compartment and in hence the protect the passenger from bas weather condition , sunlight etc.

Roof design :

In roof design I have to follow the master section also I have to do separated calculation for heat distortion test and snow load test .

Roof Design it divide into 5 different part .

1front roof rail

2 bow 1roof rail

3 center roof rail

4 rear roof rail .

5 bow 2 roof rail

All the design of the roof has follow the master section has given below and draft angle is min 7 degree .

Front roof rail :

Front roof is has designed as per the master section . as mentioned below . and the blend radius is 3 degree .

The front roof rail has designed with the offset of 32 mm from the upper body and do the law extension upto 80mm x direction and 32 degree draft angle along y direction . Then offset the upper surface 6.5mm downwards direction and first offset

Draft analysis :

Draft analysis has cleared the all the surface with more than 7 degree angle

Rear roof rail :

In rear roof rail first I have offset the flange the 10.9 mm with along y direction and the law extension command I have to do 32 degree draft angle along y direction and then after that offset the upper surface 6.5mm downward direction .

Draft analysis

The rear roof rail has clear the tooling direction with minimum draft angle 7 degree .

Bow roof 1

The bow roof 1 I have to make a offset the surface 6.5mm and make a datum plane on curve on surface 95 mm and do the law extension with 12 degree draft angle all the bow roof rail has designed as per the master section .

Master section

Draft analysis

The bow roof rail has clear the tooling direction with minimum draft angle 7 degree .

Bow roof 2

The bow roof 2 I have to make a offset the surface 6.5mm and make a datum plane on curve on surface 95 mm and do the law extension with 12 degree draft angle all the bow roof rail has designed as per the master section .

Draft analysis

The bow roof 2 rail has clear the tooling direction with minimum draft angle 7 degree .

Center roof rail

The center roof I have to make a offset the surface 6.5mm and make a datum plane on curve on surface 95 mm and do the law extension with 12 degree draft angle all the bow roof rail has designed as per the master section .

Draft analysis

The center roof 2 rail has clear the tooling direction with minimum draft angle 7 degree .

Heat distortion calculation

Heat Distortion Calculations:

We have a data to calculate

W = [1.73 x 10^(-3) x L] + [1.85 x 10^(-8) x (R^2)/t] + [ 1.10x10^(-3) x l] - 2.68

Judgement Condition : OK< 2.7> 3.1

Where

L = Roof Length in X-Direction[mm](Roof dimension in 0-Y)

R = Roof curvature

R = 2(Rx*Ry)/(Rx+Ry)

Rx = X curvature

Ry = Y curvature

t = Roof plate thickness [mm]

l = Bow Roof Span [mm]

Section Modulus

Bow 2

minimum of moment of inertia is 334.07mm^4

I = 334.07

Y = 67.89

S =I/Y

Section modulus = 4.92mm^4

Center roof 1

Minimum moment of inertia is 334.70mm^4

I = 334.70 MM^4

Y = 67

S = 4.99 MM^4

FRONT ROOF RAIL

Minimum Moment of inertia 8.17 mm^4

I = 8.17mm^4

Y=122

S= 0.66 mm^4

Rear roof rail

Minimum moment of inertia is 9.24mm^4

I = 9.24 mm^4

Y = 217

S = 0.0427 mm^4

heat distortion calculation .

SNO	PARTS	RX	RY	R	I	L	T	W	OK/NG
1	FRONT to bow roof 1	5687.67	2041.18	3004.54	458.96	2029	0.75	1.5	ok
2	bow roof 1 to center roof rail	4835.88	6864.25	5673.75	477	2029	0.75	1.9	ok
3	center roof rail to bow roof 2	3883.91	11521.98	5808.36	361.36	2029	0.75	2.8	ok
4	bow roof 2 to rear roof rail	3141.73	14936.7	5190.46	362.83	2029	0.75	1.8	ok

SNOW LOAD TEST

SNO	PARTS	RX	RY	lx	Iy	y	IY	S	ALPHA	T	QR	OK/NG
1	FRONT to bow roof 1	4826	2657	1042	2033	452	536	547	1.56*10^3	0.75	3.45	OK
2	bow roof 1 to center roof rail	3578	6548	1042	2033	354	2.58	254	1.3*10^3	0.75	6.45	OK
3	center roof rail to bow roof 2	3254	9571	1042	2033	589	2.57	1.23	1.8*10^3	0.75	4.2	OK