# 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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592 views

### How does Abaqus calculate reaction force?

I wrote a UEL for one element and compared to a reference UEL (FEM), where the results agreed satisfactorily, except the reaction force. The stress, strain, strain energy all were pretty accurate. I ...
601 views

### How Can You Calculate Force to Overcome Friction From an O-Ring Seal?

I essentially have a piston in a tube that is sealed with an O-Ring and actuated with a solenoid. The friction of the O-Ring however, is higher than estimated (guessed as far as I can tell) by the ...
69 views

Below I attached two BLDC motor commonly used for skate boards, I am confused with the calculation of stall torque for these two motors,What i need to know, What is the maximum weight lifting ...
87 views

### how do tilt-shift DSLR lenses and video projector lens shift lenses work?

For photography there are tilt-shift lenses. For video projectors there is lens shift lenses. With video projector lens shift I get perfect, undistorted video projected up to 100% above, below, left ...
62 views

### Efficient Gearing to Climb a Rope Vertically

I am trying to design a gearbox of sorts that would climb a rope from turning a gear (motor, handcrank, etc). The largest issue is that, while both the top and the bottom of the rope will be attached ...
179 views

### Anti-Squat Force Transmission

I’m trying to understand how anti-squat works in motorcycles and how the geometry plays a major role. I don’t understand, however, the reason why the force from the tires that is transmitted to the ...
541 views

### GD&T for Multiple Surfaces as Single Feature

I'm looking to get some collective agreement on a question that I have come across a few times now. When referring to features that are technically independent, what is the general consensus on ...
27 views

### Plot zero-pole from frequency response matrix

I've represented with Matlab a system with three degrees of freedom. I'm trying to plot a pole-zero map from my Frequency Response Matrix H(w) in the case of Damped-...
204 views

### How to make a cyclorotor?

I have looked for a way to make a cyclorotor mechanism which allows the blades to rock/rotate (in the picture below, its rocking I believe) to no avail. I am not able to find the required length of ...
50 views

### A Question of Coaxial Rotors and Lift

I'm only a HS physics student, so please bear with my lack of jargon. My question goes like this: In the scenario of two coaxial rotors spinning independently in two different directions, each with ...
133 views

### Equivalent Force: Hydraulic rams in H frame machine press

A 100ton H frame machine press can use 1x100 ton ram to exert this amount of force. Can 3x33 ton rams do the same job if they are applied to same area as the 100ton ram? Also in relation to a H ...
57 views

### Combining critical speeds for a shaft of variable cross-section

I am looking to determine the critical speed for a shaft with universal joints at each end, where the halves are joined by telescoping profile members. I can calculate the critical speed of each ...
175 views

### Worm Drive Calculation

I have this setup: -Pully with a mass attached. -Worm gear drive to lower the mass with a constant speed. (Section A-A) Now if we look at the cross-section A-A, we can see the worm gear drive: ...
3k views

### Deviation of Ideal Rankine Cycle from Actual Rankine Cycle

I'd been having difficulty with a problem from Cengel and Boles, Thermodynamics An engineering approach. The problem is about the deviated Rankine cycle from Idealised ones. The question I would like ...
88 views

### Why does a radiator valve require more torque after a few turns?

I'm automating a non-thermostatic household radiator valve, by replacing the knob with a DC motor and adding some support structure. You can see the system at work here: https://www.instagram.com/p/...
590 views

### IV drip/flow rate controller design

I have a question about intravenous flow rate controllers, which are controlled using microprocessors. For example: I want to control the IV flow rate, the flow is in range from 0 to 300. So, I just ...
1k views

### Stiffness of members in a bolted joint

I'm trying to calculate the safety factor against separation of members in a design that looks like this: I know how to find the bolt and cylinder stiffness, but I don't know how to find the ...
577 views

### Straight sided serration dimensioning

I have invented something and I need to have some external broaches made but I'm being asked for some dimensions I simply do not understand. I need 4 external broaches. They all have the same major ...
68 views

### What is “Yale Key, 10½ Section, change 900”

The specs say: Admittance shall be by means of a locked door and/or key operated switch, which in order to provide compatibility within Local Authorities, shall be a Yale Key, 10½ Section, ...
24 views

### Decission between several position switches and one continuos position signal for controling rotating conveyor

We plan a conveyor that will dump something into containers. A level gauge on the tip of the container will measure the heap below. The conveyor is placed on a turntable and will e rotated ...
153 views

### How big does hail need to be to damage auto body panels?

I am trying to determine under what conditions falling hail will dent automobile panels. For example, is it determined by the size of the hail, the speed of impact, force, energy, etc.? I know there ...
67 views

### problem in the calculation of pressure drop for an axial turbine

I am simulating an axial turbine. In this turbine, there are two domains. The first domain is the piping before and after the blade and the second domain contains the turbine blades. The domain ...
56 views

### Identifying coefficients to determine cutting speed for PA6 plastic

As part of a study at work, I have to calculate the cutting speed and feed rates for cutting plastic. I have found a formula for cutting speed calculation: $$v={{C_V*K}\over{T^m+t^{x_v}+s^{y_v}}}$$ ...
81 views

### How do I calculate the best mass for the highest linear speed?

I have a motor whose specifications say that its torque is 190g*cm. If I have the formula for the mass of the wheel vs radius, is there any way I can find the radius to get the best linear speed? The ...
144 views

### Problem in an axial turbine

I am simulating an known as , using CFX as a solver. This turbine have 8 blades((360/8)=45 deg=pitch angle). Due to the circumferential symmetry, only one eight of the annulus has been computed, ...
975 views

### Flow velocity in exhaust chimney - typical design value

I'm looking at a project where stationary CHP engines will be replaced, leaving as much of the infrastructure in place as possible. Current exhaust velocity in the chimney is ~42m/s and it will be a ...
193 views

### How do I make my balloon annotations circular instead of oval-shaped?

I'm getting oval balloons for my annotations instead of circular balloons even though I selected the circular setting. Is there any way to edit/revert this annotation to become a normal circle?
571 views

### Band Brake placed Perpendicular to the Diameter bisecting the Angle of Contact

I was asked the question: A band brake is installed on a drum rotating at 250rpm and a diameter of 900mm. The angle of contact is 1.5pi radians and one end of the brake band is fasted to a ...
333 views

### Accuracy of torque specs?

I am working on a project and I am defining the torque specs. I used the initial torque spec as a baseline and then went out on the floor and tested it using multiple torque wrenches. The components ...
66 views

Due to the fact that pipe flanges rely on bolts, and bolts rely on friction, it seems obvious to me that in deflecting to meet the load, the nut will immeasurably turn. So my question is - how much? ...
298 views

### Plain bearings (plastic) in backlash free joints

I need to design some backlash free rotational joints for slow and intermittent movements (device for human-computer interaction) for my uni project. Possibly loaded in any direction; the loads won't ...
99 views

### Mechanical device to simulate hinge axis external/off of part

Take a horizontal bar 10' pinned on the right end, so that there is a hinge point on the right end. Space requirements dictate that the bar must be cut in down to 5' (cut in middle and keep the left ...
1k views

### What data do I need to plot a BSFC map

I have an 4 stroke spark ignition engine simulator which takes user inputs and outputs performance data. I need rpm, torque and brake specific fuel consumption (bsfc) to plot the bsfc map. I am able ...
90 views

### Power system of the 10,000 year clock

I've heard that the 10,000 year clock will use multiple power sources (heat differential, mechanical weight, etc.), but how are they all integrated?
40 views

### How do pilots of Deep Sea Vehicles operate the control surfaces and thrusters from inside a pressure hull?

A Deep Sea Vehicle (DSV) like Trieste or Limiting Factor or now Fundouzhe have control thrusters, ballast that has to be dumped, and other equipment to operate the DSVs. But the pressure hull is a ...
33 views

### Magnetic Force - Point of Load

I am using a Magnet like this in an assembly and I am trying to calculate the torque in point P2 (see picture below) resulting from the attraction force F between my magnet and the steel part. As I ...
23 views

### Narrowing down injection moulding material selection

How do I narrow down specific values when selecting a plastic for injection moulding? My part is uniform in wall thickness and thins out where a hinge a present. Properties: Will not go under many ...
14 views

### Is it possible to have a reference pulse interpolator for a CNC machine with dc drive?

Is it possible to have a reference pulse interpolator for a CNC machine with a dc drive? it should work with alternating current drive but I am not sure about the direct current drive. please help me ...
26 views

### Linear motion with triangle profile

I am looking for a way to generate a linear motion with a triangle motion profile for my hobby project. The travel distance should be 6cm (so 12 cm for round-trip) with constant speed 1.2 m/s or ...
16 views

### Velocity and Acceleration Polygons for Mechanism

I need to determine the velocity and acceleration of point H using vector equations and drawing a polygon. Given data is shown. $\omega$2 is 5.8 rad/s and $\phi$2 is 120 degrees I know how I can draw ...
65 views

### Relation between links and pairs in Kinematic chain

I came across a equation for kinematic chain (for lower pairs only) : L = 2P-4 where L: Number of Links; P is the number of pairs how could this equation be derived ? EDIT: I tried putting values in ...
30 views

### Does anybody know where this calculation for the mass moment of inertia for an eighth of a circle comes from?

These attached photos describe flaps which are a portion of a circle and equations are attached as the mass moment of inertia, but there are no descriptions. I am using this for part of my research, ...
33 views

### Pump system with dynamic head

Given: A pump system is defined with dynamic head of 46 feet. The height between the static pressure gauge and the surface of the water is 9 feet. Assumptions: Friction losses between the tank and ...
28 views

### Shell Breathing Modes and Base Excitation

I have been reviewing "Vibration of Continuous System" by S. Rao as part of self-studying to help with work. I started reviewing the chapter regarding shells and noticed that shells have ...
42 views

### Optimizing flue gas temp for maple syrup evaporator

I have a simple maple syrup evaporator. Fuel is burned in a firebox located under 1mm stainless steel pans containing maple sap--which becomes syrup once enough water is evaporated. After passing ...
37 views

### Lowest temperature at which a spring powered mechanical wrist or pocket watch will stop operating

In the Wired article 9 Russian Adventurers Mysteriously Froze to Death. A New Theory Explains Why, it is stated that: Without body heat to keep it warm, in such cold weather—estimated to be –13 ...
9 views

### Finding the Shear Center for a Beam with 1 Axis of Symmetry

I am trying to solve this problem of finding the shear center for the given beam and I have found that e = 35.94 mm, however the solution that was shared with me, had the answer of 39.17 mm. My method ...
23 views

### Is there any way to focus the mechanical vibration or stress of an object?

I am looking for a way to focus the vibration of a metal sheet at a specific point on that sheet so that other points vibrate less. Just like light and lens. Is there any way to focus the mechanical ...