Im at university and am doing a materials project. The part I have selected is a front brake caliper adaptor bracket for oversized discs.
I know aluminum is normally used but need to make sure it’s the best or find a better material.
The question is which are the best materials to use and why? Price is not important, as there is not a lot of material needed so per weight material is not that expensive.
What factors are the most important? Young’s modulus, shear modulus, tensile strength, compressive strength, fatigue toughness? Any others? What is an endurance limit I would have thought it was similar as fatigue toughness?
All the carbon steels seen to be suitable, nickel based super alloys, titanium alloy, carbon fiber in epoxy matrix, stainless steel, aluminum (7000 series??) al/silicon carbide composite. How should I decide which is best for the product.
I have ces edupak so can plot graphs of the different properties but am not sure which will be the best properties to plot to find the best material?
Also manufacturing is important and I know so material needs to be fairly easily turned into final product. Guess cnc would be used on most materials. _________________ 94 mc28 SE
Hi there, you seem to know enough about the subject already, but i did a similar project and used the cambridge material selector (CMS) which sounds similar to the program you have. I assume they would have taught you how to derive certain material property parameters (not sure this is the correct term) that are not always obvious, but generally involve the superposition of linear selection lines of varying slope on 2D graphs of material properties such as those you have mentioned. I am surprised cost is not an important factor, because if its not you would just go ahead and use a nickel based alloy or titanium - hell why not CFRP or intermetallic? You could produce the only single crystal nickel superalloy brackets ever made, but why bother when there isn't really a difference between this and a decent Al alloy below temperatures of 500 degrees C!
In reality, you would choose a cheaper metal with good fatigue and toughness characteristics at room temperature - hence the aluminium alloy or plain carbon steel. Workability is also very important. The endurance limit applies to some metals (either ferrous or non-ferrous cant remember now!) that will not fail under even an infinite number of load cycles at a stress up to what is then referred to as the endurance limit. _________________ '87 MC16
hey ahug thanks that was helpfull. but shurld cost is not major as one is not using ramounts of the material the pack says nickel super alloy is only $40/kg so not that expensive if make a top of the line performance part bu then it needs to be worked hot.
al looks to be a great choice but doesnt it have bad fatigue toughness.
Long time since i did my engineering A level, But Aluminum wil oxidise will strees and fail quickly, you need any alloy composite? Carbon again i think will be subjust to the emilents, salt, dirt, water, not sure if i would go for that! if you are realy stuck i know someone in "MTS Edinburgh" who dose NOTHING but metal testing. and could get some material ideas for you!
Surely if you're at University studying about materials, then we should be the ones asking you!
I've made such caliper brackets from Al 5052, 5083, 6061 and 7075.
The 5052 bent, the 5083 and 6061 were great and the 7075 cracked.
As for oxidising, well why not anodize it? 6061 looks great when anodised. I could only ever get 5000 series ali to anodise grey, and the 7000 came out sort of yellowy. My anodizing technique is very crude!
I know of others that use Al 2017 for various brackets so that may be worth looking into. Never used it by choice though other than when I was in Japan.
Many companies use Al 6061 T6 for many applications in the bike world, from sprockets to caliper brackets, so that'd be my first consideration.
Ahhhhhh T6, thats aircraft grade isnt it?? Well the stuff they use in some of the componants anyway. Also used by Bicycle firms to make frames, Cannondale is one of them! but as Matt says youll need to protect the bare metal someway, the stuff i used ages ago discolours very quickly! if left bare and untreated!
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