New answers tagged mechanical-engineering
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This might change depending of what discipline you are investigating but:
homogeneous: refers to a material that you cannot distinguish different phases in it. Usually it refers to the density properties, and it's an indicator that the density is uniform when you look at it at various scales (from m to sub mm).
(some etymology: the word comes from the ...
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$\sum Fy = 0$
$F_1 + W_F = \gamma_wh_2A_F$
$h_2A_F = \dfrac{108 + m_f*g}{\gamma_w}$
From here, you need to solve this problem by iteration. For the preliminary trials, I would assume $W_F$ is negligible. Once the optimum $h_2$ & $A_F$ is find, re-iterate the result with $W_F = m_f*g = \rho Vg$ ($\rho = mass density of the material, V is the solid volume ...
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This is not an answer but to express how would I attack this problem. At any time $t$, there is a resistant force at the toe of the moving body, and the motion will continue if it is surpassed. Assume the sketch below is at $t = 0$, and $d = 0$, your job is then to find the energy accumulated between $t - t_f$ and $d - L$, in which $L$ is the length of the ...
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Monitoring has been continuous for over 30 years in critical equipment in petrochemicals. Our rotating machinery guy liked to do it in two directions; Something about rotor swirl which helped him to predict. There must be substantial info some where .
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I know of no global standards for vibration monitoring.
Like all preventive/predictive maintenance items, these things need to be equipment-specific. These are the same considerations you would apply to any preventive checks, including autonomous maintenance checks. Considerations include:
process impacts (Loss of production)
equipment failure cost
...
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This is not an answer but to question your formulation.
As you can see, due to the flexibility of the rope, at any given time its deformation is undetermined, thus affecting the angle of rotation. There are too many variables, your assumption of linear behavior is not valid. You shall try a rigid steel rod instead of the flexible rope.
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My interpretation is the maximum free water surface is limited to EL 39.0, as there is continued feeding to the tank, the pump will be started when the water reaches EL 28.0 and the pump will be stopped when the steady water surface is at EL -28.0.
In this scenario, there is a free board of 11', the actual drawndown varies depending on the rate of feeding ...
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Other than SONY, this wiki article may have provided what you need, depends on how deep you need to get into the topic. https://en.wikipedia.org/wiki/AIBO
AIBO (stylized aibo, Artificial Intelligence Robot, homonymous with aibō (相棒), "pal" or "partner" in Japanese) is a series of robotic dogs designed and manufactured by Sony. Sony ...
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Rather than getting hung up on the words, consider their usage. The authors' definition may only make sense in a specific context that that they were trying to convey.
Ductile was about the ability to draw a material into a wire. The word or its roots may even preceed quantification of structural properties, but that's somewhat irrelevant. What is ...
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Rubber is a hyperelastic material. It doesn't fall under the typical Ductile or Brittle categories.
Percentage elongation and percentage reduction in length or area basically refers to permanent elongation or reduction, after the material has undergone any sort of plasticity (i.e. surpassing the yield strength of the material). If it experiences elongations ...
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If this is still an issue, I believe the reason for this is that the computer monitor displays the peak-to-peak value and the direct measurement displays the RMS value.
2.5 mm/s (peak-peak) = ±1.25 mm/s (0-peak)
RMS(1.25) = 1.25/sqrt(2) = 0.88 mm/s
That is, 2.5 mm/s peak-peak = 0.88 mm/s rms.
The difference between this 0.88 and the 0.78 is probably due to ...
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Setting aside
the added energy requirements to compress the CO2
complexity technologies on the car you need to separate CO2 and store it (assuming its in a tank in gas form)
to my mind one important reason not to would be the following:
Burning one lit of gasoline, produces about 2.3 kg of CO2 (this is about 22.72 moles), which in Standard atmosphere ...
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An obvious solution is to design a "punch" that fits the groove, which you drive with a linear actuator. There are many ways to do that, a lead screw is an obvious one.
you could use two small rounded grooves on the "punch" to fit the string (so that it doesn't get out and doesn't get squashed or mangled).
Additionally I've put a small ...
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Mechanism you are looking for is something mechanical watchmakers have been searching for ages*. Because that is exactly what a mechanical wrirst watch does. The mechanism in question is called an escapement.
Now the classical escapement moves in pulses, but there is a sub variant known as a constant force escapement that moves at constant speed if the force ...
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Every case is different.
A rope is going to flex the individual strands until one of them snaps, then the rest of strands will fail. If the tension is applied fast the process doesn't change drastically.
In steel cables if you apply the load fast you deny the individual strands from necking and they can break randomly with sharp edges.
A beam will simply ...
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Yes it can make a huge difference.
However, this will be very much depended on the material and its behavior.
There are two factors that can have an effect:
strain rate properties
Dynamic behavior and loading of the structure.
Strain rate properties
for example, strain rate is known to have a significant effect on steel:
Figure : change of strain rate ...
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Yes. Evident by $F = ma$, and $E = \dfrac{mv^2}{2}$.
Example for the influence of acceleration "a" - a boxer would break the opponent's jaw by a fast punch but it is not likely to occur if he presses his fist against the opponent's face with the same force applied. As the fast punch creates a phenomenon called "impact" - the recipient of ...
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I have no experience in the engineering industry, but I used to be part of an undergraduate engineering competition team that designed and built planetary rovers and autonomous underwater vehicles. Perhaps I can provide a perspective of doing CAD in a small team of 10 to 20 students.
Members of the team usually have an idea of how the final product might ...
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A very easy way is to attach it to a reducing gear, a gear with more teeth. You would choose the radius of the reducing gear like this.
If your output is usually 10% above desired speed, we choose
$$R_{final}=\frac{R_{initial}}{0.93}$$ Note we did not choose 0.90 because we want to hover near average desired output speed.
By just choosing 0.93 we get close ...
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First, a big (100 or 1000 engineers) project is very unlikely to start from a blank piece of paper. A company like Boeing has designed many planes in the past, and therefore has a pretty good idea how to "guess" an initial design for a new one.
One method that works is to start from an initial "guessed" design and refine it. Given the ...
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There are multiple things going on here.
Your question indicates you have a variable input speed but want a constant output speed. The answer to this on its own would be a continuously variable transmission with a controller that sets the ratio according to the output speed. Any version that has a controllable ratio could be hooked to a simple pid ...
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For your first question - how many people work independently but collectively to finish a product or a large project.
It is done by using cad collaboration software with a master plan that linking everybody's work and updates instantaneously, or at the scheduled intervals by the lead person. For the individual draftsperson, if linked properly, you are always ...
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Can you not simply take the miles per gallon value times the Heating Value of the fuel?
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To my understanding the Hartnell governor is a variation that might be applicable to your needs.
Figure : HArtnell Governor source mechoholic
Essentially it moves the sleeve against a compression spring (instead of gravity), so - at least in theory - you could turn it upside down.
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Tip: 'KW' is a kelvin-watt (which I don't think is useful for anything). Use 'kW' for kilowatt. (Capitals matter!)
You could really simplify the problem by using the energy density of the fuel. If you look it up you should find that it's about 10 kWh/kg of petrol or diesel. 10 kWh/kg × 3600 s/h = 36000 kWs/kg = 36000 kJ/kg = 36 MJ/kg.
My diesel VW does about ...
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Not sure if this exists off the shelf, but what if you installed in line with the spinning gear a device with two weights held in place by springs, which would move outward if the centrifugal force became too high?
I believe they also have devices that will declutch the engine if a speed is exceeded, but not sure that is a desired behavior.
(https://i.stack....
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I would like to add a bit to the two answers above.
More of a practical explanation of your CAD question.
Latest CAD, CAM and CAE software allow multi-user simultaneous work by using referenced models.
That is, as you mentioned the assembly with part A and part B.
There's an assembly model that references (links) the models of the two parts.
Also while ...
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I think the sketch below may help you to find answers to your questions. Since I am not familiar with gear design, there may contain mistakes, let's see how others say about it.
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I think this will lead to an overestimation because you are assuming the load is 100% during the whole time (I would expect it to be somewhere 40 and 50% on average).
Assuming 35 MJ/L, your calculation as it is would yield about 15 L per 100 km, which is too much.
Given the average ratio of load, it would yield something between 7.5 and 6 lit per 100 km ...
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It's a massively important question. Short response: apply the concept of encapsulation.
Divide into subsystems
During development, assign design-ownership (distinct from project manager role, although may coincide in a small group) to subsystems, and to the higher level design
Define interfaces (mounting, electrical, thermal, plumbing, material flow, etc) ...
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Your question is a fundamental problem and does not have a single way to be handled. IMHO it boils down to the management of engineers and designers and is fundamental to the success of a company.
IMHO (it might be very simplistic compared to what Jonathan R. Swift might have to offer, since I've only worked in a small company with less than 20 engineers ...
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Just adding to the rest of the answers, if the door hinge is thick enough to be assumed rigid, then the offset configuration offers better resistance to bending moments in at least two axis.
i.e: For the following reference system
Case
Y-Axis bending moment
Z-Axis bending
Front View
Top View
It is noteworthy, that for a pure pullout force (which is ...
2
Generally what happens is that if when the load is removed (quasi statically) the material will return in a path which is parallel to the elastic region.
Eg. for load up to E and F the following behaviour is observed.
Notice that the slope of the red arrows is identical to the slope of OA section (region up to proportionality point).
hysteresis
If the load ...
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Question 1: Elastic recovery will always take place until the material surpasses the Ultimate Tensile Strength (UTS) of it. This means that when ever you load a material and if it doesn't surpass its UTS, then it won't fracture but will be longer in length (in a Tensile loading) than its initial length when unloaded. Between B and C, the material is on the ...
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(Assuming a direct connection to the motor for the smaller gears), the torque of the larger gear ("sun") will be equal to the sum of the three smaller ones only if the three smaller gears have :
identical size
rotate in the same direction
rotate with exactly the same angular velocity (rpm).
With the direct connection of motor to gear, if the ...
1
The gearing constrains the speed of all the planetary gears to be the same. Whatever that speed change does to the torque of each gear, the torques becomes forces acting on the center gear.
If one gear is connected to a water wheel, another to a windmill, and a third to a bicycle, then they'd all turn together, and perhaps the slow speed of a high-torque ...
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This problem is very similar to adding balancing resistors to parallel voltage sources in electronics.
What you need is less "stiffness" in the system so that when one gear loads up more than the others, something gives to unload it which serves to increase the load on the other gears.
Something like mounting the drive gears on a torsionally ...
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in your configuration all the three gears must turn with exact identical speed.
if one is slowere or faster it bring all to slow or faster or even crashes the entire system.
Many inexperienced drivers used to do that before the automatic transmission era.
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Summary: There is increasing plastic behavior and decreasing elastic behavior as the sample is strained from B to C. The transition is caused by random grain orientations and variable resolved shear stress.
With respect, the other answers generally have the right idea, but are missing the important meso-scale mechanism for why there is a non-linear shape ...
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One point of note is that the yield region is not as cleanly defined as BCD is in the image (although most books have it that way).
In reality the yield region looks like
The following image is one from many actual measurement that I took years ago (its Force Displacement).
You can see the jagged yield region after the elastic region.
The point is that the ...
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Yes; from B to C it is behaving elastically AND plastically. A small amount of plastic strain ( less than 0.2%) is mixed with elastic strain.
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Point "C" is the "offset yield point" or "proof stress" as described below.
The yield strength or yield stress is a material property and is the stress corresponding to the yield point at which the material begins to deform plastically. The yield strength is often used to determine the maximum allowable load in a mechanical ...
3
The arch has been designed to resist wind loads but just the wind load its 630 feet arch can cause.
The motto of not over designing the structure to reduce the weight of the structure to a manageable weight has lead to even reducing the viewing openings on top to 7 by 27 inches.
Over 500 tons of pressure was used to jack the legs of the Arch apart for the ...
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There are a lot of assumption in this answer.
I assume that the structure is not overengineered (although monuments tend to be). That means that the arch has to withstand its own weight, shear forces and bending moments from the wind and snow and earthquakes.
Based on the above assumption (and the additional updated) the addition of the giant vertical axis ...
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It's so the screw heads on opposite leaves don't hit each other when the hinge is closed. The heads aren't always 100% flush.
Mechanically, this compromises some load cases, but not the limiting ones.
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Staggering the screws will
give a better chance for some of them to penetrate into solid grain. and discourage toilet paper perforation pattern.
Provide for larger torque resistance.
keeping the hinge from develoing a loose play, flapping out of door jamb plane. prhibiting door settling slanted out of its frame.
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More compact configuration that fully utilizes the area of the leaf.
Avoid stresses concentrated on a single plane that is likely to cause the base material to progressively fail in shear or split.
The staggered arrangement is more stable. It provides better strength in resisting the incidental bending resulted from the weight of the door and missing/loose ...
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Because the screws go into wood and if the screws are in line then the wood will most often split between the screws in the grain direction and then the screws come loose.
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One does not want the rupture in the grips; that makes elongation and reduction of area measurements very difficult. Also, notch sensitive materials will rupture in the grip area unless the the grips are significantly larger cross-section than the gage length. For notch sensitive materials even the shoulders must have a long gradual taper to avoid shoulder ...
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The stress is not uniform near the grip because there is a biaxial state of stress.
There is
the axial force
the compression force from the grips.
That is the reason that if the Cross-section was uniform the failure would start from the grip.
the mental image is the following: If you have a ballon that you apply force from one end, and at the same time ...
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