Questions tagged [applied-mechanics]
Questions about using applied mechanics to model engineering problems.
187
questions
0
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19 views
Does FEMTOOLS have better modal analysis capabilities than other commercial softwares? [closed]
I got to know FEMTOOLS for a short time but I have not used it. Do you know or have used it and could you tell me if it has more benefits for continous or assembly systems in modal analysis than other ...
0
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1answer
27 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 ...
2
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1answer
33 views
What is the Source of the 10% Trailer Tongue Weight Recommendaton?
Throughout the trailer, hitch, and tow vehicle industry a recommendation of 10% tongue weight for a tow-behind trailer and 15% for a 5th wheel trailer seem universal. They have even been changed to 10%...
0
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0answers
14 views
How can I develop the displacement imposed frequency response function?
in theoretical vibration books , almost all of them to my knowledge, the FRF function is always developed for a system of SDOF or MDOF being excited with a unit force.
but in FEM softwares there is ...
0
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2answers
84 views
From a mechanical point of view(Physics/Engineering) why are Front-Load washers said to clean/wash better than Top-Load washers on average?
Which cleans better?
Is it just marketing or do they really clean/wash better due to some physical property or the way they work, I am asking how do they if they do?
N.B I do not intend to indicate ...
0
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1answer
22 views
Temperature logging of li-ion cells
I'm looking to measure and log the surface temperature of lithium ion cells (cylindrical and pouch). I tried using LM35 sensors with an Arduino, but, the drift was too much somehow. Any suggestions on ...
0
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1answer
35 views
Ball and Socket Wheel Concept
I am sure you all remember those prehistoric computer mouses that had a ball under it. I'm looking for any points and tips on how to create a ball and socket wheel that has an almost frictionless ...
0
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1answer
20 views
Mass inertia tensor for rod non-symmetric regarding coordinate system origin
I want to express the inertia tensor of a rotating rod (total length $L_1$) to use it in Lagrange mechanics for expressing the kinetic energy associated to the rotation with angular velocity $\dot{\...
0
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2answers
30 views
How to calculate traction force w.r.t. rotational speed of a shaft mounted at a certain angle on a surface?
I am designing a new mobile robot platform and i need a generic solution for the robot in order to establish a proper mathematical modeling. My question is about calculation of the traction force of ...
0
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1answer
36 views
Do concealed door closers exacerbate wear on a door's hinges?
Not being of an engineering background, I was first inclined to think that a door closer would reduce horizontal load on all hinges and not contribute any support in the vertical dimension.
However, ...
0
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1answer
25 views
Measuring Torque in a bicycle [closed]
How to measure torque in a bicycle?
how much newtons will produce by the pedal of the cycle ?
1
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2answers
37 views
Parallel Axis Theorem for x and y Shift
I have a quick question about the parallel axis theorem.
Let's say I have a box-like object rotated about the following pivot point
I was wondering, by applying the parallel axis theorem, would the ...
0
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1answer
28 views
Stopping Force of Irregularly Shaped Object
I have a quick question about the force needed to accelerate/decelerate an irregular object.
Lets say I have a 3D object with the following general shape,
This system is in general a gripper (gray) ...
1
vote
0answers
10 views
How is the slip calculated in Abaqus small-sliding interaction?
I’m doing research on the sliding of 2 fracture surfaces.
To do that, I’m trying to understand the Small-sliding deformable interaction in the Abaqus (2018), and I use the Node-to-surface ...
4
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0answers
23 views
Equation for the spring constant of an orthotropic, rectangular wire spring
I hope I can get some help with this problem as I've been struggling with it for a long time. I have a helical tension spring with radius $R$ and a square wire cross section and made of orthotropic ...
1
vote
1answer
35 views
Locations of max stresses in a circular beam?
If a torque and axial force is applied to a beam with a circular cross section, where along the cross section of the circular beam is the location of the max shear stress, max bending moment, max ...
3
votes
3answers
62 views
Moments of Fixed-Fixed Beam
I have a quick question related to the topic of mechanics of materials.
If I were to have a beam that is fixed at both ends and has a central point force, do moments develop at the fixed supports?
e....
0
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0answers
46 views
Are these force components right?
Would you also decompose the centrifugal force this way?
$m_{tot}$ is the total mass of the Hyperloop.
$a_c $ is the centripetal acceleration.
$\beta_a$ is the angle formed by the air bearings with ...
0
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0answers
10 views
Viscoplastic model of solder alloys
I have found some data of viscoplastic Anand model for the SAC305 solder joint of electronic devices in the literature. Does this data depend on the thickness, length and width of the joint? I mean ...
0
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0answers
42 views
Derive a Transfer Function from first principles (PID, system identification, statics)
I want to derive a transfer function of my system so I can plug it into MATLAB and use the PID tuner tool.
My system is a balancing beam with a motor on each end of the beam.
My first principles ...
0
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0answers
37 views
Pendulum-like effect
In modeling a wing with the finite element method, I am asked to consider an engine (approximated as a lumped force and moment) and it's mass, inertia, prestress and gravity contributions.
So the ...
0
votes
1answer
36 views
Calculate Rolling Resistance Experimentally
I am trying to calculate the exact rolling resistance ($F_{rr}$) of my car. The approach I am going with is a coastdown test at a low speed so no drag slows down the car. From there I am going to ...
0
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0answers
18 views
Acceleration of the rotation of three gears
Hello, I am trying to solve the question shown in the image but having some doubts in resolving the motion into its different components.
To my knowledge, the problem should be split into 3 or 4 ...
0
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0answers
38 views
Finite Element Code: Convergence issues
I am trying to code a simple FEM problem. A bar is fixed at the bottom edge, and a displacement is applied at the top. I want to apply the displacement gradually , so I have divided it into a number ...
0
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0answers
27 views
Stopping a tall structure from being blown away by a strong wind [duplicate]
I have a 1.5-meter satellite dish, and I wish to have it point directly upwards. Here is what the dish looks like with the feed in place (ignore the wobbliness of the feed, we increased its backplate ...
0
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0answers
20 views
Solving Hertz Impact ODE with Simulink
I have a question about modelling a nonlinear 2nd order ODE for an impact of a sphere on a thin plate in Simulink. Depending on the solver and solver options, my results in Matlab vary a lot. Some are ...
0
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0answers
41 views
Need help with FEA bar analysis problem
I'm trying to solve this
which is to find the total deformation of the bar.
I'm trying to implement the finite element approach, but I am getting way too large of numbers. Here is what I did in ...
1
vote
0answers
29 views
Distance travelled at articulation point of turning vehicle
Problem outline:
I'm trying to figure out the distance travelled at the articulation point of a turning vehicle with 4 driven wheels (each wheel houses a motor and can all rotate at different RPMs). ...
0
votes
2answers
146 views
Statically indeterminate fixed-pinned beam problem
F=32KN; Mf1=60KN-m; Mf2=-58KN-m; g=30KN/m I need to solve this using Force method. Find the reaction at the pinned end.
1
vote
1answer
77 views
FEA: Newton-Raphson algorithm for Dirichlet BC non-linear static analysis
I have a standard non-linear static problem to solve with FEA. I am applying displacement boundary conditions only, no external force. The equation to solve look like these:
$K(u)u=R(u)$ Eq(1)
The ...
0
votes
0answers
31 views
Stopping metallic construction held by a threaded rod from wobbling
I am working on a 1.5m satellite dish with a custom feed. The problem is that the feed is being very wobbly once slightly pushed, as shown here: https://www.youtube.com/watch?v=rAFGbEhhDZ8 (it swings ...
0
votes
1answer
35 views
Polarity of a relative angle - Knee joint angle
I'm wondering if it's correct to write:
$$ \alpha = \theta_{lg} - \theta_{th} $$
EDIT: the theta angles are defined positive in counter-clock direcction, instead alpha in clockwise direction. My ...
0
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0answers
45 views
Need help picking motor to wind a spool
The application is a motor attached to a spool to wind/unwind window blinds.
I would like to operate the motor at $v=0.2\text{ m/s}$, with a max load of 1.5 kg.
I need to know the ideal diameter ...
0
votes
1answer
68 views
Installing satellite dish to point to local zenith
After receiving help on my previous post (Stopping/reducing wobbliness in threaded rod), I've decided to come back and ask another question: how can I actually hold the satellite dish into place? I ...
1
vote
1answer
92 views
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 ...
0
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0answers
31 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 ...
0
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1answer
36 views
Soil mechanics-Geotechnical engineering [closed]
Which is more economical to improve or change the soil that is used to build a structure?
my answer is that it depends on each case, but I would like to get more information, or where to search about ...
0
votes
1answer
61 views
Moment of Inertia of a Rotor System
I need to settle a discussion on the following question:
Part A:
Find the equivalent spring constant for springs in series
Use equations of motion, sum of torques to find natural frequency of the ...
1
vote
2answers
201 views
Rotary to linear motion - how to make upside down “hammer” mechanism?
I’m not an engineer, however I think this place is the best one to find an answer to my question.
So my problem is as follows: I need to create a mechanism, preferably driven by a dc motor, that will ...
-1
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1answer
84 views
Could a spinning permanent magnet's interaction with the Earth's magnetic field propel a boat through the water?
I am wondering if a spinning permanent magnet's interaction with the Earth's magnetic field will produce a propelling force strong enough to propel a toy boat through the water. This propelling force ...
1
vote
0answers
66 views
How can I do engineering projects for money at home? [closed]
I am a M.Sc. graduate in mechanical engineering and I have experience with engineering software, like MATLAB, CATIA, and ABAQUS.
I want to know how I can find industrial projects like finite element ...
1
vote
1answer
44 views
Calculate surface area and outward normal of each face(non-planar) for a irregular hexahedron.
I am using the vector cross product to calculate each surface area and thus the outward normal. However, this approach fails when the surfaces are non-planar. So what is the best approach to calculate ...
2
votes
1answer
164 views
A way to calculate the magnitude of the moment
In my engineering textbook, I didnt understand the example given to explain the magnitude of the moment. It asks to calculate the magnitude of the moment about the base point O of the 600-N force in ...
0
votes
1answer
63 views
Approach to solve a frictional problem?
I am having a bar and surface (made of aluminum). I need to attach some material to the end of the bar so that, if I apply any force (25 N-sideways) to bar it has to stick with the surface.
Force ...
0
votes
1answer
29 views
Creep / cold flow SS304 vs A514/T1
I made a pallet lift table out of 1/4" SS304 and now have about 5x the deflection that beam calculations predict. I noticed that the machine was shipped supporting a 500lb pallet.
I thinking a few ...
2
votes
2answers
260 views
Is strain energy the same as potential energy, or something differen?
Sorry for this stupid, basic question. But I got hung up on it.
We know from Clapeyron's theorem that the strain(internal) energy of an elastically deformed body is equal to half the work
$$
U=\...
0
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1answer
35 views
Curve-linear vs. Cartesian coordinate systems: linear-elastic & isotropic elasticity tensor
For shell elements, is the elasticity tensor for linear-elastic & isotropic materials the same in a local curve-linear (convected) system vs. a local Cartesian system?
I wonder because ...
2
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0answers
26 views
Virtual work method for a disk with axisymmetric distributed and concentrated loads
I'm trying to determine all forces/reactions on a disk with a hole in the center.
The disk is loaded with a (known) uniform distributed load from A to C (all around the disk), a concentrated (known) ...
2
votes
2answers
92 views
Why do we use simple bending equation when bending moment is caused due to shear force?
Simple bending equation is derived assuming pure bending(when a couple is applied onto a beam with no shear stress).We tend to use the above derived equation when moment is caused due to shear stress?...
1
vote
1answer
91 views
FBD of folding table leg
I've drawn an FBD of one leg of the table the picture. I've a feeling I'm missing something. Am I?
