Roof challenge

Here, Given Roof styling, Develop the essential flanges and reinforcements, Provide appropriate dimension and check for Draft analysis and also submit your section modulus report on the 0-Y section CAT Part are in the below :-

ROOF DESIGN

INTRODUCTION

When automotive industries have not much Enovation, equipment, and necessity cars has no roof. But time passes it is very need to provide roof in the cars.

An automobile roof or car top is the portion of an automobile that sits above the passenger compartment, protecting the vehicle occupants from sun, wind, rain, and other external elements. It also provides classic look to the automotive. Aluminium material is mainly used because of its light weight and good strength property.

Here, I used skin data as my input to get my roof design, middle rail, front rail, rear rail and bow. My required referance extract from skin data. I used CAD tool i.e. CATIA V5

Different type of roof in Cars: -

Sun-Roof:-

Sunroof is a part of the vehicle roof that allows the light and/or air to enter the passenger compartment of the vehicle. It is either fixed or movable. The basic intention behind the use of the sun-roof is to enhance the passenger's ride experience by the use of ambient light and fresh air.

There are two ways you can operate the Sun-roofs i.e. either manually or electrically.

Roofless Car:-

A convertible allows an open-air driving experience, with the ability to provide a roof when required.

Panoramic roof: -

Panoramic roof systems are a type of large or multi-panel moonroof which offer openings above both the front and rear seats and may be operable or fixed glass panels.

Material:-

The car industry uses a tremendous number of materials to build cars, including iron, aluminum, plastic steel, glass, rubber, petroleum products, copper, steel and others.

Due to high strength and low weight aluminum is used.

DESIGN OF ROOF: -

Part Structure: -

It provides all information of roof assembly and location of roof rails. Roof rails are used to carry bulky cargo or sporting equipment overhead that can use special roof mounts which can be fixed on to these rails. They are a modern version of the old 'luggage carrier' except that they are designed to be mounting points rather than carriers.

The reinforcements are classified according to their positions

1. Front Roof Rail
2. Centre Roof Rail
3. Roof Bows
4. Rear Roof Rail

Front Roof Rail: -

Front roof rail will have open at certain angle so that necessary thing like light, mirror can be easily mount. While designing of roof it is very important to provide minimum clearance to driver side i.e.

85mm minimum and it varies project to project. Small rubber kind material called as Mastics which is used to joint the roof outer and front roof rail.

Rear Roof Rail: -

It is place where back door in mounted. It is very important to provide rear room head clearance & rear visibility criteria for safety and comfort.

The master section is as follows: -

Bow Roof 01 & 02: -

This is the part of roof which provide strengthen to the roof which have some mastic region and some embosses area.

The master section is as follows: -

Middle Roof Rail: -

The center roof rail lied betwwen front and rear roof rail, provides proper balance to the roof and also provides area for mounting of light. It has also some mastic region and embosses area and reinforcement region.

The master section is as follows: -

Joining & Assembly: -

For joining here mastic and welding technique is used, generally spot welding is preferred. After completing assembly it goes to Role Over Test which is very important to check the impact bearing capacity.

Dimension:-

Length: - 2027 mm

Width: - 1184 mm (Max), 1035 mm (Minimum)

Thickness: - 0.75 mm

Minimum Radius:- 3 mm

ROOF CASE STUDY: -

Bow – roof prediction Formula

It is very important to know that whether position of bow, rail & curvature are good or not and my curvature is good or not. So to know all these thing we have to the test at least heat distortion & snow load criteria because we can easily predict these two theoretically and roof test will do after assembly.

Roof Distortion Criteria:-

Here, we study about the temperature limit where the material get change their property so that shape of roof may change and violet the safety.

Here, We have

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>

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]

Calculation of Rx & Ry: -

Rx (Radius of curvature in X-Direction): -

Ry (Radius of curvature in Y-Direction): -

Data: -

Snow load Prediction formula: -

Qr = [Iy x t²] / [α x s x [(Rx + Ry)/2]² x 10^-8]

Note: The Qr value given over here is correct. There was a typo error in the formula given in the video.

Where,

α = My x Lx² x 10^-12 , My = Y(Ly-Y)

Judgement condition = Qr ≥ 3.1

250 ≤ s ≤ 380

t = Roof plate thickness [mm]

Ly = Distance between the front and rear roof Rails on the Vehicle along with 0Y[mm]

Length of Roof panel with the center point between Roof rail Front /Rear as the reference point of the front and the rear.

Lx = Distance between the Left and Right end of the roof on the Roof BOW [mm]

Width of the roof panel exposed on the surface.

Y = Distance front Front Roof Rail to Roof BOW[mm]

s = Distance for which Roof BOW bears divided load [mm]

s = L1/2 + L2/2

Iy = Geometrical moment of inertia of Roof BOW (Y cross-section )[mm4]

Rx = Lateral direction curvature radius of roof panel Y cross-section on Roof BOW [mm]

Roof panel curvature Radius of the Length Lx in Front view

Ry = Longitudinal Direction curvature radius of the Roof panel X cross-section on Roof BOW [mm]

Roof panel X curvature radius of length s in Side view

Y (Distance front Front Roof Rail to Roof BOW[mm])Calculation:-

S (Distance for which Roof BOW bears divided load [mm])Calculation:-

Moment of inertia of Roof BOW i.e. Iy calculated from section of modulus from take M1 value.

Data: -

Calculation Section Modulus: -

Section modulus is the direct Measure of Strength of a beam. Higher the Section Modulus higher will be the Resistance to Bending. In general, it can be stated as the strength of a section under bending.

Intersection View: -

Bow 01:-

Bow 02:-

Middle Roof Rail: -

Front Roof Rail: -

Rear Roof Rail:-

Roof:-

Draft Analysis:-

Draft analysis is the analyzing command which lets you know if your model or design have draft angle in a given tool direction.

Bow Rail:-

Font Rail: -

Middle Rail: -

Rear Rail: -

Roof: -

Other View:-

Thank You