Roof challenge

Roof:

An automobile roof or car top is portion of an Automobile that sits above the passenger compartment, Protecting the vehicle Occupants from sun, wind, rain and other external elements.

The roof itself may be considered of soft or Rigid materials. Soft tops are made of vinyl, canvas or other textile material hand-top convertibles have roof made from steel aluminum plastic or Carbon fiber Composites Your vehicle can also become ruined in an accident. Through a defect may seem insignificant at first It can lead to serious consequences. Whether your roof Was dented due to downfall or. Wrapped your roof Was dented Due to downfall or roughed up in a collision, it is urgent, necessary to find a replacement for it. The roof panel is attached to the BIW of the car with the help of front and rear roof rail. This attachment is done with the help of sealant Bow roof 1&2 are attached depending upon their length of the roof, along with the central roof rail longer the roof more, the number of roof rail, other dimensions like strength and material is governed by the factor like head room. Overall space visibility ergonomics and the rules and regulation of the starts where it is sold.

Front Roof Rail:

It is the support that is joined with the Windshield glasses. Body side, outer and inner panels. It is usually made. From bodyside. Outer scrap and therefore the thickness of the rail is 0.75 mm. A draft angle of 3-5 degree is provided for deep drawing operation. The visibility criteria and head room clearance of the passenger are taken into consideration for the bottom most flange. Windshield end and the roof end are spot welded, and the other end of the front roof rails is joined with the roof using mastic for increasing strength.

Bow Roof 1:

Bow roof center 1 is an additional stiffening member used in the roof assembly for the localized strength improvement and it is joined directly to roof itself with several improvement and it is joined directly to roof itself with several spot welding or even with mastic sealant.

Bow Roof 2:

It is like that of bow roof 1 which servers the same purpose is the previous but with a limited extend and hence it is used with a smaller cross.

Center Roof Rail:

Center roof rail or reinforcement center is used as a cross member between bodyside left hand right hand respectively .in some case the reinforcement center is not joined with bodyside the reinforcement center and bow roof are joined either spot weld or by mastic sealants.

Rear Roof Rail:

Back door and the rear roof rail got attached here with the help of masting sealants.

I maintained 0.75mm thickness for the rear of rail because if we use more than 0.75mm means there is increasing in overall weight of the car leads to low performance need more power simply weight of the car increase.

This 0.75mm is the perfect and standard thickness for the automotive sheet metal components. Thickness for automotive sheet metals components vary from 0.65mm to 0.75mm.

It is the support that is joined to the backdoor the bodyside outer and the inner panels. Inputs from backdoor design is also taken to accommodate the required clearance along with headroom clearance and rear visibility criteria while designing the rear roof.

Ditch Area:

It is the extended portion of the main roof concealed by other BIW panels and not a styling surface. Headroom clearance, visibility criteria, clearance for windshield and back door are the some of the factor to be considered while designing the ditch area.

Draft Analysis:

Draft analysis is a method of checking the draft angle on various faces of a part with a particular direction. Draft analysis command enables you to detect if the part you drafted will be easily removed. This type of analysis is performed based on color ranges identifying zone on the analyzed element where the deviation from the draft direction at any point corresponds to specified values.

Heat Distortion curvature study:

The heat distortion study plays an important role in sheet metal usage. Heat distortion temperature is a temperature limit above which the materials cannot be used for structural applications. This study is used to predict the heat distortion temperature at where the materials start to soften when exposed to a fixed load at elevated temperatures. To avoid bending or damages on roof, based on heat distortion temperature this study will predict the bow roof position on the roof to strength the roof.

Curvature study on the roof:

S.NO	Positions	RX	RY	R	l (mm)	L (mm)	t (mm)	R^2/t	W	OK/NG
1	FRR & BR1	5691.064	3025.847	3951.007	470.309	2144.85	0.75	20813941.75	1.93	OK
2	BR1 & CRR	4819.215	6819.175	5647.380	279.172	2144.85	0.75	42523867.81	2.12	OK
3	CRR & BR2	4099.904	9962.762	5809.192	293.984	2144.85	0.75	44995615.59	1.66	OK
4	BR2 & RRF	3391.354	13863.141	5449.573	432.977	2144.85	0.75	39597127.84	2.22	OK

Snow Load criteria:

S.NO	COMPONENT	IY	α	Lx	Ly	Y(mm)	S	Rx	Ry	t	L1	L2	Qr	OK/NG
1	FRR-BR1	732.97	0.966	1128.3	2144.85	447.1	396.12	3037.299	4265.20	0.75	513.09	279.15	8.082	OK
2	BR1-CRR	1799.89	1.001	1082.7	2144.85	528.3	293.64	6606.103	3794.44	0.75	279.15	308.14	12.744	OK
3	CRR-BR2	756.28	0.8	1059.1	2144.85	355.4	394.79	10313.798	4209.68	0.75	308.14	481.44	2.55	NG
4	BR2-RRF			1045.5	2144.85	548.1		15498.451	4146.42	0.75

Conclusion:

The Design of Roof front roof Rail ,Rear roof , Rail roof ,Bow Roof and reinforcement roof center by following the master section with the design parameter for the given class a surface is done.

Made the curvature study and analysis the design for heat distortion are found OK

We found bow roof 2 has NG ,so we have to ask the styling team to modify the surface and team modify the curvature.