Hood design-Week 2

Objective:-

Design hood outer panel, inner pannel and reinforcement with the given outer hood skin, master section and design parameters.

Introduction

The hood or bonnet is the hinged cover over the engine of motor vehicles. Hoods can open to allow the access to the engine compartment ( or trunk on rear- engine and some mid- engine vehicles) for maintenance and repair. In design perspective hood should meet some specific condition like pedestrian safety, hood head zone for the lock striker, force distribution when subjectrd to frontal collision ( occupant safety ) manufacturability etc.

A typical hood assembly consist of hood outer pannel, inner pannel, latch and striker, hinge , hood stay. Would stay in John a Paratus for supporting the Indian food of a Moto vehicle in its open position. The purpose of opening the engine would is for inspecting in general, replenishing cooling water and engine oil, changing parts and making the bed et cetera, common types of food status order support Road at gas day. Support roads are mentally operated at the airport effective and simple to design where is Gaston required to know man power but they are costly. Would a typically made out of the same material as the rest of the body work. This may include steel and aluminium. Drawing, hemming, planting and piercing are the common steel sheet metal operation that are used in manufacturing food in automotive industries

Design parameters

Hood thickness information

Outer panel thickness = 0.75 mm

inner panel thickness = 0.75 mm

Reinforcement thickness = 1.5 mm

Master section

Components

1. Hood outer panel

outer panels are the aesthetic element of a car. It is the styling T provides the skin of the outer panel. A shape, position and size of the food should satisfy the safety norms. So while designing the food we should give more importance to pedestrian safety. The outer panel is attached to the inner planets by humming so, it is necessary to provide required hemming plans and leaves for the hemming Operation stop we also provide basic select between outer panel and inner panel to reduce vibration.

Hood inner panel:-

Inner panel is the part that gives strength and rigidity to the outer panel. The master section represents the initials emboss shape and size. Then we provide the emboss for the latch and hinge elements after fixing the location.

Reinforcement :-

Reinforcement are provided according to the design requirements. mainly it is provided at the hinge and latch regions to improve the strength locally. Usually thickness of reinforcement will be higher than that of the inner panel and the value where is according to cost and requirement. According to the design requirement here it is given 1.5 MM thickness to both hinge and large reinforcement.

Latch trajectory:-

Latch Trajectory is given by the circle drawn from the axis point. Hinge access point is the centre point of the hinge axis. First, we can fix either to let order inch. If you have fixed the hinge position then we should block the trajectory Circle for the latch. For proper mating condition the striker access through the tip of the striker should be tangentially to the latch trajectory.

Emboss definations:-

throughout the inner panel we provide different and bushes. We can increase the stiffness of the inner panel to this embosses. The shape and size of the embosses also determines the direction of the force distribution resulted from frontal collision. The force should be always distributed away from the passengers yet in the figure the embosses are designed in such a way that the force is directed to either side of the car.

Mastic data:-

Hood commonly possess large surface area and Heming can only be provided through its boundary. We cannot use other joining techniques like welding, repeating et cetera because the loo marks on the outer panel which points its aesthetic appearance. So, mastic silence are used to stick the inner surface of the outer panel and the inner panel. Mastic silence or elastic compound that behave like rubber it is applied between the inner and outer panels at specified spots. Each spot of mastic sealants has its effect around a circular region of 80 MM diameter. mastic points are arranged in such a way that it covers the area away from the Heming which were more vulnerable to vibrate.

Deep drawing :-

deep drawing is one of the most widely used processors and Sheet metal forming apart from it use in many other sectors, it is applied in the automotive industry for manufacturing of car body parts. Deep drawing process is a forming process which occurs under a combination of tensile and compressive conditions.

sheetmetal blank is radially drawn into informing die but a mechanical action of a punch. It is the size shape transformation process with material retention. The process is considered the drawing with the depth of the drawn part exceeds its diameter. This is achieved by the redrawing the part through a series of dice. The flange region experiences a radial drawing stress and shall compressive stress due to the material retention property. This compressive stresses ( hoop stresses ) result in flange wrenkles. wrinkles can be prevented by using a blank holder, the function of which is to facilitate controlled material flow into the die radius.

Hemming:-

Heming is a forming operation in which the edges of the sheet or folded or pulled it over another part in order to achieve a tight fit. Normally hemming operations or used to connect parts together, to improve the appearance of a part and to reinforce part of this.

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In car for production, hemming is used in assembly as a secondary operation after deep drawing, trimming and cleansing operations to join two sheet metal parts outer and inner together

In car part production, hemming is used in assembly as a secondary operation after dream drawing, training and pledging operations to join two sheet metal parts outer and inner together. Typical parts for this type of assembly or hoods, doors, trunk lids and fenders.

The accuracy of the coming Operation is very important since it up at the appearance of the surface and surface quality. Material Deformations, which occurs

During the humming process, can lead to dimensional variation and other defects in parts. Typical Hemming defects or splits or twinkles in the flat material overlaps in the corner areas of material rolling. This is why it is important to provide required relief is at the corners.

These are two types of Hemming Operation

1. Conventional die hemming

In conventional die Hemming , The plant is folded over the entire length with a Heming tool.

2. Roll hemming:-

it is the role hemming process that is used for automotive sheet metal. Roll hemming is carried out the mentally Vijay hemming roller. And industrial robot guides the humming roller and forms of land. Roll hemming operation can also be divided into several pre-hemming and final hemming process steps. Roll hemming is very flexible to use and total cost for significantly lower as compare to those of conventional die hemming. However, the cycle times or much higher since the hemming is realised using a hemming roller which follows a defined path.

Final assembly :-