Questions tagged [applied-mechanics]
Questions about using applied mechanics to model engineering problems.
229
questions
3
votes
2answers
65 views
How high will a flywheel catapult launch a payload?
First off, this is not a homework question or anything like that. I'm trying to build a catapult to launch a payload using a flywheel as an energy device!
It goes like this:
The flywheel spins up to ...
3
votes
2answers
53 views
Can you use an accelerometer to measure beam deflection under static loading?
With an appropriately collocated accelerometer is it possible to retrieve lateral deflection of a beam under static loading.
The beam will be loaded and then deflect until it reaches equilibrium with ...
0
votes
0answers
19 views
how to obtain solution of this bessel equation using Frobenius method
Given this equation:
$$
\frac{1}{r}\frac{d}{dr}\bigg(r \frac{dT}{dr} \bigg) - \bigg(\frac{2h}{bk} \bigg)(T-T_a) = 0
$$
I can let $x=r\sqrt{(2h/bk)}$ and $z=T-T_a$ to obtain the bessel equation using ...
2
votes
1answer
26 views
Pressure-force limiting blocks or relief mechanism for avoiding excessive pressure over a piece
I am looking for some device that can be used for blocking a sheet of glass or other materials in position. On one side of the glass (blue sheet in the diagram) is applied a force if the force is ...
-1
votes
1answer
42 views
Deriving equation of motion of a 1 degree of freedom system
Before solving this system, note that the rigid bars $\mathrm{\overline{OA}}$ and $\mathrm{\overline{OB}}$ are rotating about point $\mathrm{O}$, not their respective CGs. To account for this two ...
2
votes
0answers
37 views
Why funnelling air in order to increase the velocity is a bad idea when generating power
Disclaimer: I’m not trying to violate the conservation of energy here; I know that’s impossible for us mortals. I think I’m either wrong or not considering something, I just want someone to point it ...
0
votes
1answer
34 views
Differential Equation for: Locking a laser's frequency with a PI controller
I think I have a good understanding of differential equations, so I would like to first try to understand my system in terms of differential equations before transforming my system into the more ...
-1
votes
2answers
63 views
Does a change in specimen dimension affect the measured yield strength and tensile strength?
I am having a hard time trying to understand the effect of geometry on a specimen's yield and tensile strength or if there even is one.
If there is an effect or not, why is it so?
Thanks in advanced!
0
votes
1answer
53 views
Would this air amplifier attachment increase a leaf blower's effectiveness?
With the start of the leaf raking/blowing season just a month away, I have been thinking of a way in which I could make my old leaf blower more effective so I can spend less time doing leaf blowing. I ...
-1
votes
1answer
49 views
What theories solve the problem of weight dispersion to minimize damage?
I assume there's some simple link to give me to answer this, but I don't know the terminology for it and so haven't been able to solve this.
The use case it to avoid having my TV put divots into my ...
7
votes
5answers
2k views
Would a centrifugal flyweight governor system slow down the descent of an object that is free falling down to the Earth's surface? (Revised design) [closed]
I am wondering if rotating flyweights would slow down the descent of a object that is free falling down to the Earth's surface.
Please reference the conceptual drawing below:
This drawing is showing ...
1
vote
3answers
64 views
Torque required to rotate object around axis using Stepper Motor for Kinetic Machine
Hey all,
I'm creating a machine to rotate a socket wrench using an arm attached to a motor shaft in order to make clicking sounds from the object therefore I'm trying to choose an appropriate stepper ...
1
vote
1answer
52 views
What causes an inflated spherical cap to look more like a mountain?
I'm working with bulge tests of materials using biaxial loading (applying pressure from one side through a circular aperture).
The materials are clamped on the edges.
The diameter of the aperture is &...
0
votes
0answers
30 views
Is a pyramid considered axisymmetric? Why so?
I read a source, I will not reference the source on this platform.
They stated a pyramid is axisymmetric. Can you explain why if yes?
2
votes
1answer
47 views
Is there a way to convert a short throw in one direction into a long throw in two directions
I have a motor that I have created a simple adapter for; this lets us attach any parts we might design to solve the final problem:
I would like to convert the motors motion to oscillating motion in ...
-1
votes
2answers
34 views
How to design internal wall separation in the PVC tube to use it as a water tanker
I am working on design of the column which contains the water tanker and the pump + electronics at the bottom.
I have tried different solutions and they failed. I would like to know your advice on ...
1
vote
0answers
15 views
Deformation gradient tensor from particle displacements in an inflating material
I don't have a mechanics background, but am trying very hard to read and understand how to approach this problem. I am struggling with understanding what's "correct" or the basic process of going from ...
1
vote
2answers
49 views
Fixed-Free End Column Design
I am currently working on a problem where I have to design a column. The structure I am currently designing currently takes the following form,
When designing the column, I know that I have to ...
1
vote
1answer
40 views
Solving for stiffness matrix numerically by a set of measurements
Is it in general possible when you have a mechanical structure (in this case I am referring to the structure in this post) and you want to determine the global stiffness matrix of this structure, to ...
0
votes
1answer
42 views
Calculate forces/ torques on a parallel spring array
I am stuck on the calculation of forces on a certain system involving parallel springs.
The schematic of the system is as follows:
The lower plane is fixed and the upper plane movable. There is a ...
1
vote
2answers
71 views
How do you find the resultant hydrostatic force on a curved surface which is not exactly semicircle
Assuming this is a pressurized chamber with hydro-static force acting on a semi circle stuck in a surface:
To find the resultant force, I would first divide the semicircle into half. Pressure on ...
0
votes
2answers
55 views
Boundary conditions for this beam deflection problem
consider the diagram above. I know that deflection is described by the equation
$$EI\frac{d^4y}{dx^4}=p(x)$$
where $L$ is the length of the beam, $E$ is the Young's module, $I$ is the moment of ...
2
votes
1answer
59 views
Generating Linear Velocity Movement?
In preparation for a Fluid Mechanics experiment, I am looking for a simple commercial ready made
apparatus to generate a linear velocity trend to prove a new theory:
https://aip.scitation.org/doi/abs/...
-1
votes
1answer
53 views
Equation governing relative motion between aircraft and store
I am reading a paper titled Conditions for safe separation of external stores by EE Covert [Link]. In Section 1 Introduction of the paper, the author has given an expression for $d$, the relative ...
2
votes
2answers
42 views
Converting Newton's Second Law Differential Form to Integral Form and Integration Limits
I am reading a report titled ``Definition of safe separation criteria for external store and pilot escape capsules'' in which the author uses following expressions.
From Newton's second law:
$$ z \...
2
votes
3answers
38 views
How to make pivoting arms move symmetrically towards each other?
I have a basic design of two arms which need to be brought together. But I tried the design using a test setup and it did not work successfully. Here is a diagram of my design -
What I observed is ...
1
vote
2answers
34 views
Dimensioning of beam pressed by screw in assembly
I need help dimensioning a screw-beam system of a press. I built one prototype but the beam is bending too much.
Below is a sketch of my press. In the middle it has a fixing screw which presses ...
-1
votes
1answer
17 views
Effect of speed of turbo fan in bypass jet engine
Why do we keep speed of turbofan of turbofan jet engine, low.
And what is the maximum thrust a turbofan jet engine., how much can thrust a turbofan jet engine produce with just compressed air.
1
vote
1answer
27 views
calculation of tension in curved chain for chain fountain (Mould effect)
https://royalsocietypublishing.org/doi/10.1098/rspa.2013.0689
A chain of some sort goes upwards, turns in a half circle (according to the drawn diagram), and goes back down.
Focusing on the half ...
1
vote
1answer
191 views
Free pre-processor for Nastran?
I want to do a non-linear analysis (possibly SOL 400) on Nastran. I used PyNastran (python module) to set-up the BDF file for a Linear buckling analysis (sol 105). However I feel like it might be too ...
3
votes
1answer
81 views
what is the physical interpretation of poles and zeros of a mechanical system?
what is the physical interpretation of poles and zeros of a mechanical system?
I'm asking things like the meaning if I have only 0 or only complex numbers. And about the number of the poles and zeros, ...
1
vote
1answer
45 views
How could I get the coordinates of the circumscribed circle giving the 3 points coords?
I have the coordinates of 3 points thrgouh which, a circle should pass . Having the coordinates of the points in 3D, how could I have the coordinates of the center of circumscribed circle ?
also : if ...
2
votes
1answer
21 views
Would an orthotropic cylinder subjected to torsion have warping?
The situation I'm imagining is the one shown above, which is the cross section of a cylinder made of alternating layers of material. The material axes are shown where 1 and 2 are in the same plane and ...
1
vote
0answers
36 views
Understanding compatibility of strains
In mechanics, we have the so called compatibility conditions, which quarantee that when a body deforms, the strains are "compatible" in such a way to no discontinuities or gaps for inside the body as ...
2
votes
1answer
71 views
Latch Mechanics
I want to make a sprung latch mechanism which keeps a door in place until a certain force is applied to the door. In the diagram attached, the force the door must release at is Fd, and the latch ...
-1
votes
1answer
34 views
Door functional or not? [closed]
Hello I am building a door and I have taken a large rectangle piece of wood for the base.
At the top-right point of the rectangle I am planning to connect it with the top right point of a large ...
1
vote
1answer
33 views
If a driver gear has larger radius than a driven gear, will a larger gear ratio result in more torque supplied to the driven gear?
Suppose a driver gear has larger radius than a driven gear. For example, we have a pinion with a main disk, where the main disk is larger than the pinion and the pinion is a follower. This is the case ...
1
vote
1answer
97 views
Driving Gearbox in Reverse
https://www.maxongroup.com/maxon/view/product/251601
https://www.maxongroup.com/maxon/view/product/gear/spur/gs45/301171
Consider that this motor-gearbox combination is backdriven so that the motor ...
0
votes
1answer
55 views
Impact of Gearbox on Motor Inertia
If you consider a motor attached to a spur gearbox with a reduction ratio of say $r=50:1$ which is then back-driven so that the motor acts as a generator, what would be the effective moment of inertia ...
2
votes
0answers
53 views
Is a Geodesic Dome (fuller dome) that floats possible? What material or engineering effort would it take?
Buckminster Fuller has popularized Geodesic Domes (invented by Dr. Walther Bauersfeld who based it on the use of convex polyhedrons), and thus, making buildings with a very large roofs that don't ...
1
vote
2answers
54 views
2nd Moment of Area of a ring
This is my first question here. I am having trouble finding the 2nd moment of area of a ring with a thickness 't' and radius 'r'. I seem to be a factor of 2 out.
What I do is I consider an area like ...
0
votes
2answers
33 views
Position vector to Velocity vector
Is it possible to derive velocity vector form position vector without unknown such as: position vector of A = (0.8)i + (1.2)j?
0
votes
1answer
31 views
Normal Force distribution of Prism
On the image below there is a regular prism which is angled by $\alpha$.
The (black) mass m1 applies a torque $M_k$. The mass m2, which is the rest of the Body applies the torque $M_s$ In the ...
1
vote
1answer
43 views
Unit of Angular velocity of Precession [duplicate]
Since the Equation for the Angular velocity of Precession of a Spinning Disk is:
$$\omega _{p}=\frac{m*g*r}{I*\omega _{spin}}$$
Where,
m -> Mass of the spinning Disk. [$kg$]
g -> ...
0
votes
1answer
27 views
small gearbox for experimental wind mill
The gear box will have little torque as I am only using a 12 by 18" wing which rotates. The two shafts I am using are 1/4 ", one form the wing and the other going the to pivot for the wing to circle, ...
0
votes
1answer
64 views
Alternatives to sawstop technology
Sawstop table saw braking system works by putting a low voltage on the blade, and when it detects that voltage shorted to ground, the blade is retracted and slammed into an aluminum block. The claim ...
0
votes
1answer
52 views
Break loose torque calculation of lock nut against rotating/acceleating bolts?
I have a Scenario where my lock nut is tightend using a prevailing torque of 14 Nm (as mentioned by the manufacturer) on to the rotor placed between bearings (But the tightening direction and the ...
1
vote
2answers
72 views
Cascaded ball bearings
Around where I live there's these soapbox/gravity kart races (google "carros de rolamentos") in which the wheels are built simply from ball bearings. As I was building my own, I began wondering how I ...
0
votes
1answer
34 views
Low-Flow Nozzles for Corrosion Spray Testing
So, for a cyclic corrosion test system, I need a nozzle or arrangement of nozzles that provides a flow rate of 45ml-140ml of salt solution per hour to an area 60cm square. All commercial nozzles I've ...
0
votes
2answers
58 views
How are the location of Gausian points determined in Finite element theory?
From the finite element theory, what is remained a bit unclear for me, is that how do we know the location of gausian points where the integration is done for each specific type of element ? it is not ...
