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Questions tagged [mechanical-engineering]

Questions within the problem domain of mechanical engineering. Mechanical Engineering can be a broad field; consider choosing more specific tags if they apply.

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1answer
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Stopping/reducing wobbliness in threaded rod

I am working on a 1.5-meter satellite dish with a custom receiver cantenna-like feed. The dish didn't come with feed arms, so I need a way to hold the feed into place. What I tried was using a 1-meter ...
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1answer
17 views

Mechanical vibration: 2 springs attached horizontally to a wheel at a vertical distance a above the center, find the natural frequency of the system

Context: introductory mechanical vibrations, 300-level engineering. ISBN13: 978-0-13-287169-3 See problem solution below As seen in the "Potential Energy" section, the author writes that the ...
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Is critical resolved shear stress the same thing as yield stress?

Dealing particularly with the Hall-petch equation, I want to know if the Critical resolved shear stress is the same as the yeild stress. I'm trying to make heads from t
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0answers
12 views

Mass of falling weight required to move gravity powered cart [on hold]

I am trying to determine the mass of the weight I need to use to propel a cart. Attached is my initial drawing of some of the forces. From this drawing, you can see that the rope passes over 2 pulleys ...
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0answers
15 views

Converting ACFM to SCFM

I'm looking for the derivation of the equation used to convert ACFM to SCFM. I keep seeing $\dfrac{P_1V_1}{T_1} = \dfrac{P_2V_2}{T_2}$, but how do you derive that?
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1answer
19 views

How to estimate a ship speed based on weather conditions?

I have data from some ships, basically the base speed for a list of RPM. But it is know that this speed is not constant and it will change mainly based on whether and load of the ship. Is it any rule ...
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11 views

Petroleum/Reservoir Engineering: Estimating Cumulative GOR (Gas Oil Ratio) & Cumulative Oil Production

I have a data set from producing oil/gas wells from multiple (separate) drilling locations. Note that a given well can either be conventional or unconventional. Overall, the data set retains info ...
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4 views

how to get laminate stiffness matrices (ABD) in APDL ANSYS

I am trying to perform structural analysis of composite pressure vessel in APDL/ANSYS. I have completed the solution and now I want to extract ABD matrix.Do anyone have an idea about this?
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22 views

How to slide 2 small pieces of metal into each other

I'm trying to build a keyboard addon for my smartphone (https://gitlab.com/xengi/mkbd65). The last challenge I'm facing is how the two pieces, namely the smartphone and the keyboard should slide back ...
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1answer
20 views

shifting weights and locking in place at different angles

Hi i would like to ask if there's any ways i can shift weights and lock it in place at different angles (180 degree to 90 degree) without using electronic devices- preferably using wood as the main ...
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2answers
38 views

Does a tank of liquid nitrogen increase in total internal energy after emptying?

Suppose there's a 10 liter perfectly-insulated sealed tank of saturated liquid nitrogen at 4 bar. Therefore the fluid has properties, $\rho=740 \,\frac{\text{kg}}{\text{m}^3}$, $m=7.4 \,\text{kg}$, $\...
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0answers
35 views

Mechanism that moves two parts linear to each other

I'm designing a machine that will seal plastic tubes. The idea is to clamp the tube with two beams. These two beams have to move away to let a piece of the tube through, then those beams should move ...
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0answers
17 views

Aerospatial engineering [on hold]

Can sombody explain me how to calculate the friction of air e.g. a rocket traveling at a speed of 20km/s? Am a GR12 science student, and I want to make a rocket. The speed that I put (20km/s) is just ...
1
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1answer
23 views

Mechanical tolerances on a CNC machine

I have a project which involving several mating parts and also shaft guided through bearings, my issue here is that I don't have much experience with tolerances and manufacturing processes and I ...
0
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1answer
24 views

Screw Dislocation and Edge dislocation

If in both cases if there is an application of Shear Stress then why do we have Screw dislocation in one case and Edge dislocation on the other?
0
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1answer
32 views

calculate number of cylinders and volume in a turboprop

I've been given the following: CL (lift coefficient) $\eta_p$ (efficiency of the propeller) $n_p$ (number of revolutions of the propeller) $n_e$ (number of revolutions of the engine) $\eta_g$ (...
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1answer
16 views

Which material index should be maximized for a component in a Car's manual type HVAC?

I was doing a case study on the plastic used in cars for controlling the AC in a manual type system which actually snapped in mine it just rotates according to the knob position in the dashboard, ...
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2answers
26 views

Ideas needed: how to tilt a panel side to side [closed]

requirements: a panel of wood 4 ft long by 2 ft wide laying flat this panel should be able to tilt side to side (2 way) the weight on the panel will be about 250 lbs up to 400 lbs. controlled lift of ...
0
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1answer
22 views

defining the dimensions of a bucket elevator chain link

how to define the shape of a heavy duty chain link when the pitch of the chain and the traction load that the chain is subjected to is known? lets say i consider the traction load as the maximum load ...
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0answers
25 views

What formula can be used to calculate the motion that will be created by unbalanced magnetic suspension?

I would like to know what formula can be used to calculate the distance that a maglev device will travel if it were to have unbalanced magnetic suspension. Please reference the drawing below. Say ...
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1answer
28 views

what should be the size of gate? [closed]

what should be the size of gate? if street 8 ft according to house map Car entrance gate 11 ft can corolla grande car enter into the gate easily with some moves?
0
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1answer
23 views

Steering with momentum

I'm thinking of making a RC tank that should be simple as possible. But I'm not sure how to make proper steering for the tank. I googled about tank steering and found (for me) complex solutions as ...
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0answers
8 views

What bending test and torsion test standard are recommend for a surfboard?

I wish to find a bending and torsion test standard for a surfboard (non-prismatic) that is roughly 2000mm long. The closest I've found for bending test is probably those ones that are designed for ...
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0answers
17 views

How do I find deflection and strain energy in this case?

How is the load transferred to the rocker beam? How do I find the deflection if the joint is a flexible joint?
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0answers
23 views

How to attach a wheel to a turning axle for a ball machine

I'm trying to make a DIY tennis ball machine. However, I'm not quite sure how to attach the wheels to the steel rods, which will be attached to the motors. In other words, the wheel and the rod should ...
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0answers
17 views

How can I increase the strength of this clutch without shearing my bushings?

Here's the setup: (C) is a clutch. Beyond (C) is the source of torque. The belt (D) transfers the motion from the clutch to the sprocket (B). (B) then transfers the motion to (A) by way of 9 ...
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0answers
16 views

How to test Cross Wire Welds

What is the best way to test the weld strength of a cross wire weld? For example, a wire grid with .212 dia wire x .212 dia wire. I cannot find any solid information online for testing cross wire ...
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0answers
32 views

Decision criterion if bolted joints are loaded concentrically or eccentrically

When dimensioning bolts I have to decide if the applied load is concentrically or eccentrically to the bolt axis (according to VDI 2230 but I think in other approaches too). But how do I decide and ...
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0answers
9 views

Physio tilt table using counterweight

Hi i am currently doing a project regarding physio tilt table. Is there any simple mechanism where i can use to tilt the table at different angle? no electronic mechanism involved.
2
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0answers
35 views

What is the optimal shape of a beam subject to three point bending?

Assume we have a beam with density $\rho$ that is subject to three-point bending according to the image above. The beam cross section is rectangular with the variable height $H(x)$ and constant width $...
1
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1answer
36 views

Choosing a proper BLDC motor for lab centrifuge

I'm trying to make a swing rotor centrifuge and find a proper BLDC motor to reach 6000G with capacity of 4x50ml Falcon tubes. I did the calculations roughly but I'm not so sure about them and also ...
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0answers
25 views

Why the Tensile modulus is always larger than Tensile strength?

I can't figure out this huge difference in values between these two mechanical material properties. When its refer to flexural strength and modulus there's a difference in value (if the material is ...
0
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1answer
35 views

Question about walmart doors

Do Walmart store doors open or do they stay closed if someone is standing on on the front pad and someone else is standing on the rear pad? (if Walmart doors using sensor pads) I am asking this ...
1
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1answer
30 views

Build Device for Emitting Weak Air Bursts at Specified Frequency

I'm a neuroscientist interested in building a device to replicate the following study. https://www.nature.com/articles/s41598-018-24924-9 Essentially, they sent air through a nose catheter to ...
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0answers
27 views

which motor can v use for wheel chair [duplicate]

I am doing a project on controlling wheels of a wheelchair. The diameter of the wheel is about 25-30 inches, the weight which the wheelchair is supposed to carry is upto 80 Kgs and it should run at a ...
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0answers
9 views

material model or force model?

I ran milling test (measuring forces and torques between the tool and the sample) on samples in order to characterize the material properties and define a material model to be implemented in a haptic-...
1
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2answers
44 views

Can a simple application of two forces have two different outcomes on a rigid body?

[Summary: If two forces are such that the component of one of these forces forms a couple with the other, than which of the two cases (obtaining resultant via adding forces or obtaining moment and a ...
0
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1answer
15 views

Centroid and toppling [closed]

A uniform block is in the form of a square ABCD of sides 2 m and a unit thickness. E is a point on AD such that ED = xm. The portion EDC is then removed from the block. What is the maximum value of x ...
2
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2answers
71 views

How rubber and other ductile materials absorb impact energy

I learnt that, there are two types of weight plates in strength training, cast iron plates and bumper plates. The bumper plates are coated with rubber material so that if dropped comparatively ...
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0answers
16 views

Thermowell NPT at 70bar

Is it safe to use a 1/2" NPT connection for thermowells when the process pressure is 70 bar and temperature is about 85°C ?
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0answers
12 views

Why do auxetic materials have higher energy dissipation rates

Below is an extract from a thesis called "Auxetic Structures: Towards Bending-active architectural applications" on page no. 80. In a NPR (Negative Poisson's ratio) material the energy ...
0
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1answer
28 views

Force required to deform sheet metal

Hi all. I am building a machine to deform sheet metal into corrugations. I have attached an image that I got off a presentation from MIT's website. In the example, they provide a formula for the ...
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0answers
9 views

Why are entropy measures needed and useful for analyzing signals in the industry?

Currently, I am very into the use of entropy measures for estimating the complexity of time series. There are already many new definitions of entropy proposed. But, in the beginning, it is still ...
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0answers
11 views

Find the impulse of a semicircular plaque rotating around an normal axis

I have some trouble finishing this exercise. Hoping someone can help me or at least guide me in the right direction. Ex: Given a semicircular plaque of radius R and mass M, which rotates around a ...
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0answers
20 views

Apply the Impulse Theorem over a material point of mass 'm' under a force 'F', when the velocity is constant

I have trouble finding any help with this exercise, as my course is literally useless. I hope someone can help me, once they see what I've tried so far. Ex: Over a material point of mass 'm', acts a ...
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1answer
24 views

What kind of bearing should be used for free rotation under load?

Let's say I have a 300 rpm motor and a roller connected to it's shaft and I would like to use it for pulling fabric from a printer-kind machine. But think that printer's printing speed is changing ...
0
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1answer
42 views

Calculate bearing forces

can someone tell me how to calculate the bearing forces of the two bearings? I can't get any further because I don't have the angle for the second bearing. I don't have an idea anymore. F = 20KN q0=...
0
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1answer
31 views

Which is more important XY plane thermal conductivity or z direction thermal conductivity?

Im seeking an alternative to thermal grease/ pastes. I was researching graphite pads when I stumbled across the soft PGS line from Panasonic. I need to choose a suitable thermal interface material ...
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0answers
11 views

time interval selection for RMS of vibration

What is the general practice for selecting time interval for RMS calculation for vibration data (mm/s) Should it be linked to the the frequency of the motor or the sampling rate? Thanks!
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0answers
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Multiple sensor data to WiFi visualized on React Native app: Guidance [closed]

Objective: I want to connect multiple sensors to an item of equipment and visualize the data real-time on an iPad. Mock of Desired Output: Question: I need advice on the best methods to use to ...