# 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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### Find the internal bending moment, Mc

A 7meter,m, long cantilever beam whose weight per meter is 19Newton, N, carries a load that varies uniformly from 43N/m, (Newton/meter), at the inbuilt side, point A, to 0 at the free end, point B. ...
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### Can the debris found in seawater compromise the sealing of a subsea check valve?

In the event of a subsea check valve opening and debris lodging in the region where sealing takes place, could that make the valve not close when it should? Would that happen to debris of any size? If ...
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### Automatic Powder Detergent dispensing in washing machines - Concept Building

I have seen the technology for liquid detergent Auto - Dispensing in washing machines where we load the detergent at one go only and the machine automatically dispenses it according to its need for ...
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### Shape of a beam that is bowed under compression?

Suppose you have a uniform beam, such as a piece of plywood that is 4 feet long, six inches wide, and half an inch thick. Suppose you cause it to bend by attaching, for example, a string under ...
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### Infinite Solution in Truss Problem by Method of Sections

This is the problem, I need to find forces in members 6-8 and 3-8. I have made a horizontal cut cutting across 3 members but I find out that I am only able to formulate 2 independent equations, one of ...
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### Counterweight requirement and platform design for motorised speaker stand stability

I recently bought my dream speakers (Dutch & Dutch 8c), but at the cost of having to preserve a minimalist interior for the sake of household peace. To that effect, I plan to construct motorised ...
41 views

### Optimal aspect ratio of a cylinder under internal pressure

I was trying to imagine an ideal cylindrical vessel under internal pressure. Assuming it is a thin walled pressure vessel. I.e. For storing a given Volume of contained fluid ( ie volume of cylinder) ...
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### Can changing the topology of surface water initially hits change how much it splashes?

I am designing a crude funnel to feed into a portable dishwasher. I was not allowed to attach to water lines so I am stuck with pouring 1.5 large pitchers of water into it. I am designing a funnel to ...
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### Does the magnitude or range of interaction of a force affect which layer dominates the mechanical response of a multilayered structure?

Suppose I have a two-layered material, with a stiff and thin outer layer (high E) and a soft (low E) and thick inner layer. Intuitively, it feels like the effect of short-ranged forces (e.g., van der ...
1 vote
80 views

### Is it possible to use two sets of stator blades after each set of rotor blades in an axial compressor?

I am currently designing an axial air compressor for a project, and I require the stator blades to reduce the velocity from 50m/s to 2.5 m/s in each stage of the stator. This requires a ratio of the ...
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1 vote
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### AutoCAD circle dimension annotation meanings

What do the following annotations mean in this AutoCAD drawing mean? R1.25 TYP (circle/hole Left) 2XØ1.0 (circle/hole Right) Ø1.25 (circle/hole Bottom) Based on ...
1 vote
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### IPx8 rating test

Do I need to perform all the lower IPx(1-7) rating tests to achieve an IPx8 rating or covers the IPx8 rating test all the other ones.
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1 vote
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### Static analysis of a lead screw and disc friction

I'm doing a static analysis of a square thread lead screw. I think this site gives a good description of the problem. Screw threads statics To calculate the moment on the thread the mean radius of ...
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### Induce vibration on metal ball

Suppose that I have a hollow, metal ball that lies on a table. How do I induce a vibration on this ball? I want to be able to control the frequency, so it is a forced vibration (not natural vibration)....
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### Welding bot arm

I am trying to build a tool that could help someone/something weld. Being very close to a MIG or TIG welding gun may be dangerous/undesirable. Welding needs to be done in a straight line (which can ...
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Surface plates come in three grades: AA, A and B. The AA grade has the best flatness, while grades A and B have respectively 2 and 4 times less accuracy. Grade B is still much flatter than normal ...
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### Optical table without holes

Most optical tables have holes. Are there also optical tables without holes? Or do these things have a different name?
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### Force and motor calculation on a moving chain sprocket system

I have a chain sprocket motor system used to move a load up. Usually I think the load would be the charge use for calculation and the torque should correspond to the load times de radius of the ...
1 vote
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### Bending Reaction Force

I am trying to determine the reaction force my bend tooling will see in a simple sheet metal box and pan break. From the book "Sheet Metal Forming Processes and Die Design by Vukota Boljanovic&...
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In this question, I solved the convolution for triangular pulse and the solution was Now take k = 1, m = 1 , And as R = Ku/P0, R = So, for t<td u(t) is a function of t and for t>td its a ...
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### Some questions about linear rail systems

there are many linear rail system configurations. Some with only one lead/ball screw in the middle and a moving platform with wheels aligning outside/inside/on top of one/two framing rail(s). Others ...
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### How to compute the torques of a network of rotating objects with cycles?

I am trying to figure out how to compute torques in a network of rotating objects. I assume that each object has a given moment of inertia, and some objects are accelerated by external means. The ...
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### How to measure the rotation direction and speed of a ring on a finger?

I am trying to create a device that can measure the rotation of a ring on a finger. Basically there's going to be two rings on the finger, one that rotates and one that is stationary. The idea is that ...
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### Changing the relative equilibrium position for a 2-mass spring-mass system

I am trying to solve a double spring-mass system that is positioned vertically (I currently have the pendulum at an angle of 0 in my code below). I derived the system of ODE's required, and I get this ...
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### British Standard Steel BS5S82 propagation properties

I am looking for propagation data for the BS5S82 material (case hardened). I checked in MMPDS and ESDU but to no avail. does anyone know where I can find this data? Or at least similar materials in ...
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### What practical use is knowing the extrusion direction for a piece of polycarbonate?

I noticed after cutting this piece of polycarbonate that there is an extrusion direction indicated. Can that be useful for cutting or other downstream use?
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### Is it viable to "convert" petrol buses to electric?

As part of sustainable transformation, a city is planning to replace its fleet of 300 petrol-powered buses (part of its rapid transit system) to electric buses. 100-each were bought 7 years ago, 5 ...
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### What is the difference between 7201 vs 7201 BEP Single Row Angular Contact Ball Bearings?

What does BEP mean when applied to types of ball bearings?
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### How do I find the pitch for the fly press?

To solve the problem first I need to find the pitch of the screw to find the shearing stress, is the stroke 45 degrees per 5.75mm or 90 degrees per 5.75 mm?
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### I would like to know the formula for calculating force on a 90 degree bent second class lever arm as shown in attached figure

What is the formula to calculate force F2 given L1, L2, L3 and F1? (updated: wrong question asked. originally it said: "What is the formula to calculate force F1 given L1, L2, L3 and F2? Now ...
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### How estimate the error of chemkin 2.55 results?

I've been using chemkin 2.55 for preliminary calculations of premixed laminar H_2 and CH_4 combustion and in some of the calculations, the solver fails. There is a way to hypothesize the calculation ...
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If we take the moment about A from the $F_{BC}$ will make the body want to rotate counter clock wise but If we take it from the point C it will make the body rotate clock wise whats the mistake?
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### How to modify a ball valve to make it cryogenic

I have designed a manual non-cryogenic ball valve in SolidWorks (based on this tutorial: https://www.youtube.com/watch?v=pYsU1gfx-00) My aim is to modify this CAD design so that it becomes cryogenic (...
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### Are all autonomus vehicles (self driving cars) electric vehicles (EV) or are some also internal combustion engines (ICE)?

Are all autonomous vehicles (self driving cars) electric vehicles (EV) or some are also internal combustion engines (ICE)? I was having a discussion with my friend and he was insisting that all ...
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### How to calculate the direction of shear stress due to shear force on a circular cross section?

For a circular cross section, we know that the shear stress due to a shear force at the boundary (the radius of the circle) has to be tangent to the curvature. This is so that we have no radial shear ...
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### Behaviour of a mixture of ideal gases

If we have a mixture of ideal gases can we consider the mixture also an ideal gas? This holds true in air for example where we consider it an ideal gas, when oxygen and nitrogen are considered ideal. ...
28 views

### How do rotate a picture on a wall once every 24 hours?

I have a picture with various day and night scenes that I would like to hang on a wall and have automatically and uniformly rotated once every 24 hours. The picture is roughly 55cm in diameter, 2cm ...
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1 vote
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### How do I find the volume flow rate for a circular air duct?

My assumption to solve this problem is to find the average velocity on each circle then get the average velocity between the 1st and 2nd circle and then find the volume flow rate between circle 1 and ...
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### I don't understand how the pneumatic control precession actuation on the Brennan Monorail's gyros further balances the vehicle

I linked a YouTube video from Primal Space, The Self Balancing Monorail, discussing how the Brennan Monorail works. @6:40 timestamp the narrator explains how the pneumatic pressure "[pushes] the ...
35 views

### Help Designing an Electric Wheel Hoe: Identifying Required Materials and Torque Control Mechanisms

I am currently working on designing an electric wheel hoe, and I need help determining the required materials for its construction. The goal of this project is to create an automated version of a ...
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### bearing if it was not invented at all

Can anyone here be able to explain with figures , why there was a need of bearing with shaft . What would be the case if bearing was not invented at all ?
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### What kind of test should I run for a newly built lab scale reactor assembly?

I am a new graduate student working in thermochemical energy storage research. I have built a lab-scale model reactor for running hydration reactions. My advisor has asked me to run test of the ...
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### What strapping mechanism is this?

What should I google to find the strap from the picture? It looks like a screw is used to tension the strap, which is exactly what I need. I've already spent some time trying to find a manufacturer ...
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### Is it possible to conduct a completely random Quality Test?

I work in the aerospace industry and would like to utilize simple, mass market COTS assemblies as critical components. Let's assume it's a simple solenoid valve. Rather than create a contract or ...
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1 vote
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### What is fracture toughness and how is it different from the strength of a material?

Strength is just the amount of force that an object can take before breaking, so what is fracture toughness?
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### What's the difference between ductility and stiffness?

As far as I understand they both relate to the amount of deformation based on a given amount of stress.
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### Belt conveyor roller spring

I wanted to know if anyone could help in this area. I want to create an inclined conveyor belt where, when a cargo box reaches the top of the conveyor belt, the rollers sequentially move down (maybe ...
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### What will happen if you attach the negative pole of welder to the rotor of the motor or the body , will that cause problem?

I have built a machine that rotates a cylinder to weld it, I have to attache a negative pole to the cylinder which is connected directly to the rotor of motor, the motor is controled by an Abb vfd ...
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### Mathematical descritption of spur gear undercut

I'd like to a plot spur gear in python (using matplotlib, but that is not important..). I've already worked out the involute curves, which can by parametrized easily and which define the main part of ...
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### homework : torsors of constraints: Coulomb's laws

Bonjour , j’ai un devoir maison sur les torseurs mécaniques en lien avec la loi de Coulomb et Statiquecet je n’arrive pas à résoudre! Pouvez-vous m’aider s’il vous plaît?! Je met le sujet en photo ...