New answers tagged

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In this kind of questions, I believe that most of the attention should be focused on the general approach and the philosophy of attacking. Afterwards, each individual may proceed by writing its own equations and solving them in its prefer way. In our particular case, I guess you examined the whole structure, realized that there are 4 reactions (Ax, Ay, Cx ...


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The question has not defined any section properties so we assume all members are rigid. Then by inspection, we see this structure reduces to a 2 member frame AB and BC connected at a hinge at B and supported at pins on ends. AB is at 45 degrees angle and BC is arctan(5/15) = arctan(1/3). EDIT After the OP correcting my arithmetic error. $$ \Sigma M_a= -...


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Brake torque usually means torque at the engine crankshaft, while there is no loss of power or toque due to transmission, powertrain or in your case the chain and gearbox. You would have to subtract those losses if the indicated torque is the wheel torque.


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the rate at which heat is added is so fast that the piston has no opportunity to move during the process. Furthermore, when the piston is at the top of its stroke (which is where the heat is added) the crank-and-connecting rod mechanism yields a finite residence time of the piston in that position for a span of crank rotation, which means that even though ...


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Hydraulics can be precise, down to ~ 100µm. However: hydraulic pistons [...] used in conjunction with a positive displacement pump and using a large hydraulic transmission ratio the issue of precision could be sorted out, and the incompressibility of the fluid would help to keep backlash to a minimum. This is not how this high precision is achieved in ...


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Tempersonic cylinders will monitor the position very accurately but are very pricey.


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The curve of a spring loaded cam is certain curve called exponential spiral with the unique property that the angle it touches the wall of the crack and a horizon remains the same (13-14 degrees) no matter haw much the cam expands. This small angle means the force applied by the cam to the crack is always $F_{horiz}= W_{weight}*cotan(13)= W*4.3$ Which ...


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This is a hugely complicated question that's not going to be answered both accurately and briefly, because there's too many variables presented by the real world. So I'm going to make some simplifying assumptions, to give you an idea. What I'm going to present is a simple lever calculation, but it'll almost never apply to the real world. Let's say that ...


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According to a couple of textbooks on machine design and assuming that your FBD is correct, the maximum bending moment occurs at the centre of the shaft. For a point load, it is equal to: $WL/4 = M$ Where W is the point load and L is the length of your beam. $(200*10^3)*1/4 = 50*10^3 Nm = 50*10^6 Nmm = M$ According to the maximum shear stress theory ...


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I would calculated the I being allocated to two different materials, foam and paper. one way of getting a sense of the difference between the two is to let the paper beam on its side flatwise, and measure the E of the paper by neglecting the contribution of foam, if it is not paper on both sides glue 2 back to back to make it so. Because in that ...


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I think your convergence tolerance is not enough. Since you obtain first few solutions with low convergence requirements you are moving away from the real results for the next solution steps. From the code, it seems you are using unrealistic values. In example, total displacement is 5. The tolerance is 0.01, they are crude numbers. So it is not easy to ...


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If you are using standard Gauss quadrature, from the formulation, you determine the coefficients (weights of Gauss location) and their locations. You cannot arbitrarily decide their locations. Here are some examples: http://edwilson.org/BOOK-Wilson/G-inter.pdf


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You design the system for a demand that it should meet, 3x 100l/s in your example. If the demand is higher, the sytem will likely fail to deliver the actual demand. If the demand is lower, no problem. On the network side, you know the pressure you want to deliver the water at. You could supply valves at the tap that deliver only (say) 100l/s at 4 bar, but ...


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You can define the h and beta constants, either in a cell or as a defined name. After that, you can create a column with the theta parameter and another column with the calculated y parameter. The formula for the y should use the IF and AND functions. Suppose the theta parameters are on column A. The formula should be something like =IF(AND(0<=A1,A1<...


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As recommended by @Solar Mike, the most "professional" solution is to let the end-user decide. Give them some input mechanism (a textbox, slider or dropdown, for example) so they can define which value to adopt. This is what you'll see in basically any modeling software you'll find in the wild. However, it's also very important to note the observations made ...


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You have a tall skinny skid-steer vehicle, and you're trying to run it on a surface with a high friction coefficient. So the wheels are constantly grabbing and letting go, grabbing and letting go. Try making either the front or rear pair of wheels castoring.


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Your connection of the wheels to the robot enclosure (suspension) is flimsy and has too much free play. It starts to jerk and gives enough kick energy to the flimsy box to keep it dancing. And the skidding of the wheels resonates with the vibration of the robot. To improve the stability without having to use electronics self balancing chips: Use an ...


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Make it user definable and provide the info about the ranges as you stated. Consider whether you should limit the extremes of value...


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Model airplane motors run at 50000 RPM with ball bearings; I don't think that your limit is due to speed. Basically, the assembly you picture will have the friction of, and be as rugged as, just using the inner bearing. The outer will just be going along for the ride (and adding weight and expense to your assembly).


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You will increase the friction due to two sets of balls and lubricants with the races. Also, this will cause more play in the system... If it worked and gave an advantage then it would be used by the F1 teams...


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I think the problem is most Americans are too lazy or more interested in having fun ( A K A liberal arts courses). Other than medicine; engineering is the most reliable area to get a good paying job . Now if you want to be a multi-millionaire , you need to invent some new kind of computer chip or develop a new social website. But if you want a good job with ...


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Usually because dog clutches are engaged when the shafts are stationary - lathes are a good example as they change speeds when the work is stationary and the tool dis-engaged.


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Validation: Are we building the right product? Verification: Are we building the product right? Validation is the process of making sure that you have objective evidence that user needs and intended uses are met. ... Verification is typically making sure that you have objective evidence that specified requirements are met. It is usually done by tests, ...


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Here's an illustration to explain the difference. Suppose you were creating an accounting system for Enron, before it collapsed. The specification said you need to ensure that the output assumed that 2+2=5. Verification is asking the system "what is 2 + 2" and getting the answer "5". Validation is discovering that the Securities and Exchange Commission ...


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You likely did both, but with different processes. You create a mathematical or computer model and you check that it matches the ideas that underlie it. In a computer model you check that you haven't made mistakes in the programming. In a mathematical model you check that you have used the right equations (or whatever) and evaluated them correctly. This is ...


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By experience, it is not a good idea to take any standard value or manufacturer value. Just check your chain on 10 degrees and on 25 degrees for a very long distance, on the limit of your chain, with no arrow, so on a flat ground. And just make your numbers. When you need to make a high precition work, you can not just take the values of one specification ...


0

Why not just use a standard salt spray cabinet ? I am sure it can use different salts other than sea salt. Those we had were roughly 4 ft. cubes which may be big for your work , but may have future uses. And a standard unit results are easy to compare to literature and/or publish. And as a standard unit it would have some resale value. I don't remember the ...


2

You have the right idea using a shoulder screw. In between the two pieces, use flat washers and a springy Belleville washer. A Belleville washer, also known as a coned-disc spring, conical spring washer, disc spring, Belleville spring or cupped spring washer, is a conical shell which can be loaded along its axis either statically or dynamically. A ...


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Search back-pressure regulators. Basic idea is they have a dome with a membrane diaphragm pressurized to the control pressure. If the incoming pressure is higher than the dome it pushes the membrane up and shuts the flow. This is a link to one. back pressure regulator


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Here is a trick you can try. Cut the silicone edge so that the edge dimension (for lack of a better term) is a little smaller than you final finished dimension. Now make a temporary casting mold for the cut edge such that the inside edge of the mold adjacent to the cut edge forms a wall , the gap between the cut edge and the smooth mold wall is sized ...


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Your raw material will come in the form of a large spool of sheet metal containing a strip of steel hundreds of meters long. You will need an unspooler to feed steel off the spool and a straightener to take the curvature out of the steel strip. Then you need either a punch press or a shear to cut the sheet metal blanks to size and trim their corners. To put ...


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Thought experiment - Given a free body $B$ that is being acted on by forces, find its instantaneous center of rotation $P1$ and its instantaneous center of zero acceleration $P2$. Does this let us solve for the center of curvature for any point $P$ on the body? To do so, we need the acceleration vector at $P$ and the velocity vector at $P$. That lets us ...


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This is not a statically determinate system. To find how the load splits between the members, start by finding their stiffness. Since the materials and cross-section areas are the same, the stiffness is inversely proportional to the length. Length of AC = $L\cos\theta$. If the stiffness of AB is $K$, the stiffness of AC is $K/\cos\theta$. Now consider a ...


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Just bring the wire down to the hinge and have it go inline with the hinge so it rotates with the movement. This is done on car tailgates and works fine. Some wires fail but only after several years...


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you can use a small spring loaded roller for window shade. They cost in the range of $20 and many hardware stores custom cut them down to something like 6 inches. You can remove the shade and wind your wire around it. here is a photo.


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let's call the tension at the bars at B and D, T1 and at C, T. We see that $T_1=T\frac{ \sqrt3}{2}$ $$P = 2*T_1 +T= T +2 T\frac{\sqrt{3}}{2}=2.73205\cdot T$$ The share of C bar from P load will be $$T=P\frac{1}{2.73205} $$ $$ \delta_c= \frac{Pl_c}{2.73205EA}= \frac{Pl\sqrt{3}/2}{2.73205EA} $$ The extended length of the C bar will be $l_c= Pl(\sqrt{3}/2) ...


1

These phases can be quite ductile due to their layered structure at the atomic scale, naturally as others have suggested here, it depends on compositions and stoichiometry. Under compressive conditions, high levels of performance can be achieved. This can be further enhanced by fabrication of metal-max phase composities. Generally, crack propagation is the ...


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I made one for my son's camera. The issue is usually with the bearings. I used 2 pairs of bearings taken from those "spinners" and put them on a threaded rod. Used double nuts to "just" load the bearings to provide some damping and he had good results when he was taking videos while skiing...


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I'm going to guess at what's happening from your description. In general, the "moment" on both sides of the pivot (weight x distance) should be close to equal. You can have slightly more weight at the bottom so it wants to stay upright. Inertia is what keeps things from tilting when you start or stop moving. If you have weight just at the bottom (or a ...


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the crank handle is connected to the little black box, inside of which there are gears that rotate the metal shaft you can see running through the box and across the back of the table support. the right hand end of that shaft enters the support leg on the right which has another gearbox in it that rotates a shaft leading down the length of the support leg. ...


0

The noise you hear is the engine running at the idle speed. To provide minumu energy for lubrication, charging the battery, air conditiong, water pump etc. In newer cars it has been eliminated for duration of intermittent stops to save fuel and pollute less. The computer will start the engine the moment you release the brakes. The gear box, manual and ...


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Thankfully, I once took an Automotive engineering course. It was two years ago, but I still remember something... Of course, my answer is open for improvement, so if there is any constructive criticism, please go ahead The gas pedal is the controller for the throttle (think how much air is going into the engine), and this, in turn, controls the fuel ...


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