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1

Simple and short answer is it depends where do you want to use Steel or Aluminum, and what is your target. If your target is to use a material so that it will not suffer from any plastic failure or fracture when subjected to extreme loading conditions, then you have to choose a material which will have higher yield and tensile strengths (that is why steel ...


4

When Zeppelins were designed, only non-sparking materials were allowed for them so the hydrogen gas that invariably seeps from the gas bags would not find an ignition source. Steel did not qualify. But this is admittedly a rare example. The other answers which mention the second moment of inertia are spot-on, though. If you build a load-carrying shell you ...


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Some engineering aspects, related to designing end products (my experience is in prototypes and small-volume production): Machining costs (accounting for time and tool wear when milling/turning) are so much less on Al alloys that the costs of extra material can be tiny in comparison - if you're starting from billets. Al is also easy to melt, so casting is ...


2

Wider tubes and beams are stronger against bending and less susceptible to buckling. Look up second moment of area. There is a limit to how thin you can make a tube before it becomes impossible (or very hard) to weld. With aluminium you can make much wider tubes which can still be welded. Just compare modern aluminium bicycle frames to older, high-end steel ...


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TL;DR: Materials perform differently under different loading conditions. Some applications are more suited for steel others for aluminium I will try to give another more general perspective/approach, using the concept of material indices (mainly other users gave perfectly adequate explanations of the differences between bending and tension and stiffness vs ...


3

And, in addition for sheet metal application like aircraft skin the aluminum could be 0.040 " ( 1 mm) thick ; the equal steel would be 0.013" thick . The steel would be so thin it would cause handling problems and , I expect other problems in the real world. PS ; maraging steels are good for NASA but not much use in the real world. Regular Q&T ...


20

I believe it has less to do with strength and more to do with stiffness. A rod of aluminum of the same length and weight as a a steel rod will be just as strong (force required to break) but have three times the cross-sectional area which hugely increases the second moment of inertia by nine times (it scales to the fourth power of distance/length which is ...


6

Sometimes the strength isn't required, so size for size, aluminium is lighter. e.g. bicycles often use aluminium screws to hold the bottle cage to the frame. The size of the screw is set to be comfortable to handle, and to accept the same size Allen key as other screws on the bike. But, it doesn't need to be super strong as it's not taking a critical or high ...


1

Aluminum has a couple of favorite properties. rust resistant. easy to extude decent strength its ideal for uses where one needs decent strength combined with light weight but enough meet to paroved space for drilling bolt into to attach brackets and or other parts. Engine block is a good example. Aluminum windows and shelving is another one. they strong ...


0

This answer is to point out the possible reason for the "wrong" result getting from the superposition method. The method of superposition is valid and is desirable for this problem, but your assumptions on the support rigidity could have been wrong, thus causing the mistake. The end of the beam on the right (point C) is sitting on another beam ...


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The brackets don't play a role unless they have some Moment or external load acting on them, or their self-weight is significant, which is not shown here. This is a typical problem and the solution can readily be found in many design aids. by searching for a two-span beam with a concentrated load on the mid-span. An easy way of calculating the reactions is ...


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For rectangular or square you are pretty much limited to the manufacturer and his reps. Some distributor may happen to have an inventory containing a size you want, but it would be chance. Round tubing is different because some distributors will be able draw down or expand inventory to produce custom sizes; for a price. Also , with round , some distributers ...


1

There may be multiple sources for your requirements, off-the-shelf purchases, not manufactured on spec. I have constructed cylindrical telescoping assemblies by using 4130 cromoly steel with appropriate wall thickness. If you consider that a common wall thickness is 0.058 inches, a tube with an outside diameter of 3.00 inches will have an inside diameter of ...


0

Before my answer, I need to point out what IMHO is the most significant difference between fits and tolerances. fits usually refer to a mating of two components (an assembly). In engineering terms, the "fit" is the clearance between two mating parts, and the size of this clearance determines whether the parts can, at one end of the spectrum, move ...


2

TL;DR IMHO, this is something that think has its roots to older times, where the strength design of gears required tables and charts Like solarMike said, they are essentially the same thing. I don't think many people nowadays pay too much attention to this detail. IMHO, the reason for the existence stems from the different need. Like you stated, (some ...


0

So basically this is the ratio of turns. However for shafts that is sufficient while for gears the tooth speed becomes useful. Just depends how you want to calculate the system.


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