Hood design-Week 2

                                                                     HOOD DESIGN

INTRODUCTION:

HOOD:

The car’s hood consists of an inner and an outer panel. The inner panel provides strength, while the outer panel is just a metal cover. The underside of the hood is often covered with a sound-absorbing material. like aesthetics, Some high-performance cars have ‘hood scoops’ which channel outside air directly to the air filter, which gives improved performance and efficiency.

 LATCH TRAJECTORY : 

The hood latch on any car is used to connect the hood release cable to the hood locking mechanism. If it breaks you will no longer be able to open the hood using the hood release in the inside of the car, which will be problematic the next time you have to enter the engine bay.

The trajectory path is perpendicular to the striker then my hinge position is correct. if these are not perpendicular opening and closing of the hood becomes hard.

The hinge axis and striker axis are parallel. 

Lock-up Latches play an important role in fixing timing problems, especially for hold timing closure. A lock-up latch is a transparent latch used to avoid large clock skew and mitigate the problem in closing hold timing due to a large uncommon clock path. 

HINGE:

 Hinges are used to opening and closing of the hood. without losing alignment. it connects the hood and engine compartment.

The same as the spring hinge, usually use spring to provide force to close the door and provide a mechanical or hydraulic damper to control door close speed. That can prevent door slamming problems while auto closes a door. Spring hinge This is a spring-loaded hinge made to provide assistance in the closing or the opening of the hinge leaves.

LATCH: 

A latch is a striker. wich placed over the hood and it's used to hood locking with engine comportment.

MASTIC DATA:

Adding a Mastic seal improves the NVH of the hood. mastic seal is one type of hard rubber it will join the inner and outer panel of the hood. mastic sealant improves the strength of the around 80mm diameter.

EMBOSSMENT:

The Emboss feature raises or recesses a profile relative to the model face by a specified depth and direction. The embossed area can provide a surface for a decal or painting. A recessed embossed area can provide clearance for another component in an assembly

REINFORCEMENT:

Reinforcement provides latch and hinge region it provides and improves strength locally. the thickness of the reinforcement is more than the inner panel thickness according to design requirement hear it is given 1.5mm

PADESTRAEIN SAFETY REQUIREMENTS:

The hood of most vehicles is usually fabricated from sheet metal, which is a compliant energy-absorbing structure that poses a comparatively small threat. Most serious head injuries occur when there is insufficient clearance between the hood and the stiff underlying engine components. A gap of approximately 10 cm is usually enough to allow the pedestrian’s head to have a controlled deceleration and a significantly reduced risk of death. Creating room under the hood is not always easy because usually there are other design constraints, such as aerodynamics and styling.

Many pedestrian crashes involve a forward-moving car  In such a crash, standing or walking pedestrian is struck and accelerated to the speed of the car and then continues forward as the car brakes to a halt. The pedestrian is impacted twice, first by the car and then by the ground, but most of the fatal injuries occur due to interaction with the car.

HEMMING:

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

There are various types of hemming operations:

Conventional die hemming:

conventional die hemming is suitable for mass production. In die hemming, the flange is folded over the entire length with a hemming tool. Normally the actual hemming is a result of a farming operation in which the flange is formed with a hemming tool after the drawing and trimming operations have been completed

Roll hemming:

Roll hemming is carried out incrementally with a hemming roller. An industrial robot guides the hemming roller and forms the flange. Roll hemming operation can also be divided into several pre-hemming and final hemming process steps. Roll hemming is very flexible to use and tool costs are significantly lower as compared to those of conventional die hemming. However, the cycle times are much higher since the hemming is realized using a hemming roller that follows a defined path.

DEEP DRAWING:

Deep drawing is a form of metal stamping where the depth of the draw is typically greater than its diameter. In practice, it is possible to produce long, narrow, cylindrical parts with a length that is significantly greater than the outside diameter of the part.

PROCEDURE OF HOOD DESIGN:

• Initially class A surface offset 2mm to the downwards direction.
• create the boundary need on c section create limits and create boundary
• create parallel curve give the support and distance of 20mm. curve been offset to 20mm give fillet.
• then offset the surface to 4mm and will create a boundary same as above. offset the sketch 22mm using the parallel curve option split the surface with the parallel curve. create a surface between two splitting surfaces using a multisection solid option.
• Offset the surface 25mm and create boundary than will create paralell curve offset to 35mm
• aplit the surface and combine the surfaces with using multisection solids and give the fillets.
• then create abosements on inner panel and removing metal to reduce the weight of the hood to folloimg design considerations.

OUTER   PANEL:

• Create surface from skin surface of the outer panel.
• offset 3.5mm and create boundary
• then c reate a paralell curve 7.5mm split the surface with paralell curve 
• join the surfaces and give edge fillets 1.225mm
• make a symmetry of the surface on other side. join the both sides and go to part design give7.5mm thickni for the outer panel surface. 
• give edge relief at corner of the  hood 

ASSEMBLY:

ASSEMLE THE HINGE, LATCH, INNER PANEL AND OUTER PANE TO MAKE CONSTRUCTION TO JOIN TOGETHER.

CONCLUSION:

In the hood all parts like hinge, latch, and inner and outer panel are designed the required conditions.we can conclude the hood can be utilized for the vehicle. and also considering the safety of pedastrain of the hood has been designed under safety regulations.