Design of backdoor

DESIGN AND DEVLOPMENT OF BACK DOOR ASSEMBLY:

THEORY: Back door the rearmost BIW commudity in an automobile . The general purpose of the  back door is to cover the boot space and provide safety to the rear of the car .Generally the back door is supported upon the c pillar and roof of the car 

MATERIAL:

The material section for the commudity depends upon the cost of the project .Aluminium is bettter suited for better developing the part as it can be cast and does not require reinforcement for strenghning the part but,is costlier.Steel panels are generally used as they are cheaper but require reinforcements.steel also tends to increase the overall weight of the car

The general purpose fo the back door are same as that of the bonnet of the automobile with few changes

In the project ,we are going to develop the inner panel of the part of the part from the given styling data and also will develop various and also we will develop various reinforcement for the part

DESIGN CONSIDERATION:

• Rear visibility criteria 
• stress distribution for rear collision
• Reinforcement for hinges ,gas stay and lock and lock and stricker mechanism
• weight of the part
• boot space

MECHANISM:

The hinges for the back door are mounted at the rear end of the roof part.The hinges are then fastened with the help of the screws .Depenging on the curvature the selection for hinges may vary .If the back door causes interference with the rooof curvature a panograph hinge can be used which can help overcome such problems

Depending upon the weight and cost of the vehicle. spring powered or gas stucks can be used as lifting mechanism .Gas structs are costlier then their spring powered counterparts but require less human efforts to operate the mechanism .Gas struts are costlier than the spring powered counterparts but require less human effort to operate the mechanism. These days every OEM provides gas struts as standard in the vehicle.

EMBOSSING: Embossing is a metal forming technique in which a protruted shape is created on the sheet metal part or body .Embossing helps in increasing the local strengh of the part .By creating emboss we can also divert the impact force on the part towards hinges and c pillar to avoid fatal casualties during the accident.

In a study published in IRJET , the major impact forces during the collision on back door travels in the shape of the Y character of english language that is why the shape of the major emboss design is developed as Y . To improve the local strengh of the region

REINFORCEMENT:

Reinforcement are necessary to improve the local strengh in the part .As removing material for hinges and latch stricker mechanism the strengh of the parts drop significantly to overcome this issues we can provide reinfocement at proper places .generally ,the reinforcement are welding after the panel is developed

MASTIC SEALANT AND HEMMING:

After developing the inner panel , it is joined together with the outer panel with the help of the mastic sealent and hemming process 

Mastic sealent is a silicon or rubber base adhesive substance which retains its elastic properties even after the querying.It is highly adhesive in nature and increase the strength of local regions,generally a butyl based variant is preffered by the automakers around the world

Hemming is the process in which the edges of the outerpanel is rolled flush over the inner panel ,the process creates a seam joining both the panels together .During the hemming process relief is provided at the corners to avoid stress concentrations