Custom Search




Home About Me Projects Composite Material Info Help My Projects Contacts



Light Bracket


Ok before I get into the details of this project, I think an explaination is in order as to why I decided to add lighting capacity to the car. The stock head lights and fog lights do not put out very much light and while driving home from my workshop I nearly hit a deer because I couldn't see it standing on the side of the road. Therefore I decided new lights were in order. After doing a bunch of research on light styles I settled on Hella FF1000 driving lights. Conicdently, they were also on sale so I bought 2 sets of 2 lights.


Each light has a single stud protruding out of the bottom of light where it can be attached to a base plate. I experimented with steel, PMMA, and Aluminum as materials for a lighting bracket. There are only a few mounting points in the front of the car that are easily accessable so the material must be as stiff as possible. Weight also had to be considered as I would prefer not to hinder vehicle performance. I opted for 1/8" aluminum plate because it provided the best combination of stiffness and light weight properties.


Finished Bracket

 

The bracket above was my first attempt at a rigid design. I bent the aluminum where possible to improve rigidity but ultimately the bar was extremely flexible and would not be enough to support the four lights. The reason the bracket has to be stiff is because any vibration to the bracket, which it will see very often being for an automotive application, causes a strobe light effect from the lamps which lowers visibility and can disorient the driver.


My first idea to improve stiffness was a carbon fiber wrap of the aluminum core. The carbon is much stiffer than aluminum which will act as a core material. Normally, an aluminum carbon hybrid would not be used because of the potential for galvanic corrosion. However, I already had an aluminum base and this is a prototype so I went for it! To avoid corrosion you have to completely paint the part so that neither carbon nor aluminum is exposed to the elements.


This was the first composite wrap that I have done and the resulting part proved it. I had trouble controlling the wetted out fabric because I did not stick well to the aluminum. I used plastic wrap to hold the carbon in place but in the end, the carbon won out and I was not able to wrap the entire part as well as I would have liked and I am not confident with the bond. If I were to make the part again I would use either full carbon or a foam core.


I found that the carbon wrap did very little to improve stiffness so I decided against adding more carbon and opted for two aluminum supports in the center of the bracket. After installing the supports I noticed a very big improvement to the point where there is almost no strobing effect. Only over large bumps or on very uneven roads is it noticeable. I believe a slightly altered design along with a full carbon build will allow me to achieve the stiffness I am shooting for.


To be continued...



Copyright © 2008 Bar One Composites