New answers tagged

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It quite simply means that when you are doing e.g. a check for the maximum X-force, you should use the Y-force and Z-force (and any bending moments and so on, if applicable) that occurs in the same load combination, and similarly for the other forces. Note that the procedure you describe, may sometimes be significantly on the unsafe side in with respect to ...


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I have been in 100 steel mills and never noticed a nitrogen system. However it seems they could use inert gas blasting somewhere. And nitrogen would be so cheap and convenient because steel mills will generally have a cryogenic oxygen plant. Generally they are off site and may be owned by someone like Linde. Very simple to lay a nitrogen pipe next to the ...


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it can't be a sphere because the clamp limits the expansion to that diameter. I would expect that if the pressure resulted in a displacement equal to the clamp radius that you would have a sphere.


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Solution Example 1: The object on the table would require a minimum force of $Mgk$. Example 2: The simplest way to the able the amount of force required to move the door hinge that has friction would be to look at a cross section of the component. The cross section would be a circle with two forces being applied. These force would cause torque which will be ...


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Take a look at the illustration below, which is how I understand your question. You're asking, what would be the minimum value for the blue arrows in order to make each object move? First, let's look at the simpler case - the red box. I don't think this needs another diagram - you've rightly stated in your question that if there is a coefficient of friction ...


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The minimum force required to swing the door open would not be equal to the minimum force to push the object off the table. Pushing the door that is attached to the door hinge would create different minimums of force required to push the door open as you could push the door at many different areas. In order to push a door open, you would need a certain ...


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They are less likely to be flipped over, blown away or turned inside-out in strong winds, because the gap allows the air that would normally be trapped to escape, but the second "cap" umbrella directs some of that down and toward the sides, providing some counterforce at the same time.


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They are designed to let the hot air out that collects at the top. Remember any hot fluid tends to rise, so allowing the hotter air to be vented helps cooling. I there is a gentle breeze will it make much difference - well looks good...


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I found a JPL article on it, but did not locate a CAD file (let us know if you find one). From the article it sounds like both wheels are quite close to the same with the main change being the tread. I think the image is likely photoshopped to be side by side rather than rendered side by side; so the shape change is likely less drastic than it looks in the ...


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One approach is to use the following pieces of information: A uniform distributed load (a force) can be represented by a statically equivalent point load. The point load will have the same total magnitude as the distributed load and will act at the midpoint of the equivalent distributed load. Moment = (Load) * (Distance from load to the point where summing ...


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Logically I would use 4 bolts. Since you expect a moment to develop in the y axis and x axis you ought to have bolts suffice to resist those forces with a safety margin of 1.15 of the maximum allowable force. An additional 2 bolts through the vertical face would be a good idea by extending the lip upwards to the top of the bearing case that these new bolts ...


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By observation, I have 2 moments about point F being the fulcrum. There are therefore 2 loads about point F of equal force but due to equilibrium we need to add more force on the shorter end of the lever to reach equilibrium. In order to calculate the forces across the entire system in equilibrium we recognise that the resistive force is through the midpoint ...


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Torque will drop off with speed for the Brevini external gear motors in your datasheet (OT200 series). Unfortunately Brevini doesn't publish torque / speed curves below 1000 rpm. Here is a comparable graph from Vickers for their CR-04 internal gear motor: Without providing a bunch of sources, external gear motor performance rapidly drops off with decreasing ...


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The switches are activated by the current in the trolley wires itself. Next to the switch is a small sign saying "power" accompanied by an arrow. When the driver applies power with the accelerator, the switch switches in the direction of the arrow. To go in the opposite direction, the driver does not apply power, and allows the bus (or streetcar)...


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So 10 kg for 2 meters means it is 5 kg per meter. Now load on the left hand side of the fulcrum is 0.465 = 2.3 Kg. Point of application of this load is 0.23 meters to the left of fulcrum. Similarly, load on the right hand side of the fulcrum is 1.545 = 7.7 Kg. Point of application of this load is 0.77 meters to the right of fulcrum Now consider moment about ...


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To catch the dust in a 50 cubic meter shop requires an air transfer rate of about one complete air change per minute. That means your fan has to pull in at least 50 cubic meters of air in a minute and stuff it through the filter. Your computer fan runs at 156 cubic feet per minute which is 4.5 cubic meters/minute which means you'd need more than ten of those ...


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You calculated the $\sigma_1$ = $\sigma_2$ at the end of the major axis. Calculate the semi-major axis as distance to origin, $a ={(2 \sigma_1}^2)^{1/2}$. In your first equation, you left off square in the $\sigma$ terms.


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In general the idea of bolt connections is that there should be no stress on the holes themselves. The purpose of bolts is to push the surfaces together so that the friction between the surfaces takes on the stress. So its important that the torque on the bolts is correct and the primary force direction isnt upwards in this case. (If it is bolt from sides) ...


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For multiple "spots" on a road, train an overhead, high-speed (maybe), sensitive, thermal imaging camera on the road. All else being equal, higher pressure from a vehicle passing over a "spot" will cause it to heat up more from compression, deformation, and destruction. The material should be briefly hotter along the "heat tire ...


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Depends on the load. If the load is the size of the single motor then that might be better, but if the load is half the full power rating often, then using one small one and bringing in the second as needed may be better. So you need to understand the load. A similar situation is often found for boilers where there is a leading and lagging boiler according ...


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Generally you want more than 24 teeth in a gear to avoid having an undercut tooth profile, if you're using off the shelf 20 degree gears. Spur gears you also want to have at most a 5:1 ratio between teeth. Your smaller gear (pinion) should be of a harder material than it's mating gear. If possible have the greatest common factor between the number of teeth ...


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Probably the best option should be select the least used gear (this is what I would have done in this case). I know the multiple gear system (i've operated a lathe in the past) and there's some gears that I've never used (and neither my predecessor). So if you're using the geartrain the best option is to use some gear less usable (and with less wear) for ...


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A possible method is that the circlips hold the front cap to the assembly which is slid into the housing and the rear cap holds it togther with the 4 cap screws, given there is little axial force generated by the gearing system. The frint cap can also be a press fit into the casing especially as the section does not show any o-rings...


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There appear to be 4 thru holes on the front cap (1 is missing due to the section view). There are probably tapped holes in the ring gear, screws keep the cap in place. This could also sit in a housing with stops next to the front and bottom housings.


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Maximize economy by not using the wide pedal in the middle ( aka brake). It converts kinetic energy to heat which is all wasted. Such as ,take your foot off the gas when you see a stop sign, don't drive up to it and slam on the brake. It also saves wear on the brakes; my car has over 80,000 miles on the original pads and they will easily go past 100,000 ...


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If the car computer is reporting zero miles per gallon, it is due to the math involved. Most cars will stop injecting fuel above a certain rpm when the "throttle" is closed, as part of economy design, but x number of miles per zero gallons is dividing by zero. Instead of displaying an error, it shows 0 mpg.


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When you use engine braking to go downhill, the car ecu can reduce the amount of fuel needed to keep the engine running - even no fuel in some conditions. So the onboard computer can report 0 fuel consumption. Also the computers are not perfectly accurate, see my answer here: https://mechanics.stackexchange.com/a/76400/10976 Once you let the engine idle, the ...


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A one-meter cantilever shaft supported by a single ball bearing is not going to work regardless of the bearing's specs. All cantilever shafts and rods when spinning go into an increasingly unbalanced whiplash motion bending the shaft like a quadratic graph rotating about the X-axis with the centripetal force constantly increasing, leading to breaking the ...


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The wires are usually soldered to the rings, there may also be a clamp type joint as well. On dynamos, where there were some 40 wire ends coming to the commutator, each had to be soldered to the correct segment - a job I remember fondly... What you then do with those rings is to split them so each ring is in two halves and then you cam make a commutator...


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Simply put this is a textbook example of what not to do. The geometry of the connection, a solid bar to a narrow bolt invites stress concentration at the necking where the bolt enters the rod. The heavy disk will rattle and slowly wear the bolt threads out, allowing play at the connection The play of the disk will cause intense momentum back and forth ...


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The plate allows for small amounts of angular misalignment between the input and output shafts.


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The duplicate activity H should start from the end of activity G. otherwise you are stating that the duplicate of H can only start once H is completed... The duplicate of activity K starts from the end of activity F. When checking these diagrams, you just have to read the story in the diagram back to match the information in the table. If you list some of ...


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It's wrong and same wrong information has been disseminated in a whole variety of books and has just endlessly been copy/pasted over & over Dynamical pressure is not pressure, it's kinetic energy. Only way how it can be turned down into pressure again is if you brake it down, which isn't what happens in the inlet of the pump. Only relevant thing for ...


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First of all, welcome to Stack Exchange Engineering! I think what you're looking for is how the forces work through the tool, not power transmission (which is work over time; power transmission would be more like power going through a flexible Dremel attachment). But this is a great question, and recognizing that it isn't just a simple thing puts you way ...


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Many ways of transmitting power, mechanical with a steel cable with opposing winds or hydraulics using oil or compressed air come to mind. A datasheet for a product will explain the product but not always all the details of the parts used to make it.


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The curves aren't "transferring" energy, they're preventing the most kinetic energy loss. A Euler spiral is a curve along which a body will experience the smoothest changes in centripetal acceleration. Friction is directly related to centripetal acceleration, so the path with the least amount of centripetal acceleration integrated along the length ...


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"Low-profile cap head bolt" would describe it also. Googling that returns images like but the accepted answer is technically correct.


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I think I understand where you are stuck - it appears (I don't "speak" Matlab) you're trying to solve u directly, without adressing that u goes into Re. Here's what I'd do: Guess $u$ for the smallest diameter, calculate $Re$ from this $u$ to arrive at a new $u'$. Repeat/Reiterate by calculating $Re$ and a new $u'$ until the difference between $u$ and $u'$ ...


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I'm curious what material they currently use in these cellphone holders? The recrystallisation temperature of tin is about 30C, so conceivably it could work as a non-toxic alternative in lieu of lead.


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If the flow rate is 5ml/min, and you want to know how long a tube it will take 1 min to pass through, you’re effectively asking how long a tube contains 5ml. Volume of a cylinder is $\pi*r^2*h$. 5ml = 5000mm^3. Pi*r^2 = Pi*2mm^2 = 4pi mm^2 Your length therefore is 5000/4pi or around 400mm.


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I can't answer your class question; but, when I worked in a foundry in the real world for a few years, gates and risers were designed by experience ( no computers then) . However , there are still matters like "hot tops" ( exothermic riser topping,) superheat ( adjusted for pattern complexity), length and thickness of thin sections, etc. Mold temperature and ...


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Here is my simple answer of how tires generate traction [frictional] forces for movement by Method/Process #1 in the diagram, Hysteresis: Think of Hysteresis as the amount of 'deformation' a piece of rubber is capable of, rubber being an elastic/deformable material, and specifically tread rubber, when it comes in contact with the irregularities of a road ...


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Since the pink linkage sits above the blue arm in the post, it has no problem reaching up to the trangular part when blue arm is raised. When blue arm is lowered, the pink linkage doesn't reach as far up the blue arm and starts to pull back on the triangular part, erecting the orange arm


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In this case, we say that $\epsilon_{axial}$ ($z$-direction in your diagram) is positive by convention. Then, for a normal material with a Poisson's ratio $\nu \ge 0$, $\epsilon_{transverse}$ ($x$- and $y$-directions in your diagram) will be negative. The fact that the material is isotropic means we have no way of distinctly labeling one direction $x$ and ...


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