Questions tagged [stresses]
The stresses tag has no usage guidance.
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1answer
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Resolution of forces and state of stress at a point
Is resolution of forces similar to expressing a vector as a linear combination of some other vectors in linear algebra?
Similarly, Is the state of stress at a point in 3D similar to expressing the ...
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1answer
42 views
Stress analysis for the same configuration but different material
The same geometry and the same free body diagram. However, if we replace the material from steel to glass, for example. How does that influence the analysis?
Two things I think are
1. steel is ...
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1answer
37 views
LS DYNA Material Model 163, Modified Crushable Foam
Question is on the meaning of input variable TID within material model 163 of LS-Dyna 971.
Definition of TID variable.
TID: Table ID defining yield stress versus volumetric strain at different ...
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0answers
57 views
How to calculate the thickness of the residual stress layer generated by a machining process
Machining a metal part will create residual stresses on its surface due to the deformation that the process introduces to it, is there any model to estimate how thick will this stress layer may be?
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0answers
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How to calculate the required thickness of a material to withstand a certain force or acceleration? [closed]
I am using a sheet of a certain material to dampen a product. Now, I have been looking at different soft dampening materials, and they're all defined by their durometer scale and other factors.
...
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2answers
30 views
Loadcell / strain gauge sizing for a joist
I am looking to use some load cells (foil based type) to detect presence for home automation within in a room. I was looking to mount some loadcells to the joists for the floor (UK Based house so ...
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1answer
46 views
Is it true that if the structure damaged or corroded, the stress will be lower?
I am comparing the stress results between original or non-corroded model to corroded model.
I found that the stress value in non corroded model is lot more bigger than the corroded model,
is it ...
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1answer
30 views
How to calculate residual strength of a corroded structure from their stress values?
Currently, I have an actual entire corroded bridge model in the FEM analysis in Abaqus
I want to estimate the residual strength of this bridge due to corrosion
from the output results in the Abaqus, I ...
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2answers
43 views
What exactly is the thin wall assumption in regards to beam cross sections?
What does it mean with respect to calculating stresses on a beam undergoing loading and when should it be applied?
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34 views
strength of eggshell
It is a known fact that beams and spheres have the ability to carry relatively high loads.
Beams are seen in bridges and other structures even since the days of ancient roman architecture.
Spheres ...
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3answers
76 views
Do scaled models reflect strength characteristics of full size
Lets say you want to build a bridge out of carbon fiber. This has never been never been done before, and it's super expensive stuff. So your goal is to use as little material as possible, but ...
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2answers
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Thick walled cylinder theory - Stress/strain in ballooned out tube
I want to work out how much I can expand a piece of rubber tubing before it ruptures. The wall is 0.75mm and the ID 5mm. Hence I am working out the stress/strain from thick-walled cylinder theory ...
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2answers
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Why don't car engine piston-rods (or similar parts) fail as often as other car parts?
Anyone who has owned a car has ultimately dealt with failure of a sensor (parking), or A/C failure, battery shutdown or a tyre puncture. Part breakdowns like these are pretty common, at least ...
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1answer
30 views
Mohr's circle: maximum normal stress tensor
Given:
$$
\sigma_{ij}=
\left[ {\begin{array}{cc}
-20 & 60 \\
60 & 90 \\
\end{array} } \right],\quad i,j=x,y
$$
I want to find the principle stress tensor $\sigma_{ij}^{pr}$.
...
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1answer
49 views
Base Support for a Tree house
I am building a tree house in my backyard and it is going to be relatively simple. There are no parts that require drilling into the tree. The whole house is propped up by four 4x4 wood supports. I'm ...
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1answer
38 views
What is symmetric?
What is symmetric?Please explain geometrically and in terms of displacements. I have encountered this while looking up for engineering strain and true strain values have totally different compression ...
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1answer
44 views
2-D Plane Stress Transformations
My strength of materials book provides the following equation to determine the x-component of the normal stress acting on all possible planes of a two dimensional element.
$$
\sigma_{x^{\prime}} = \...
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0answers
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Internal stress tensor associated with centrifugal/centripetal load
I have some trouble to understand the relationship between internal stress tensor and the external traction force (in this example, the traction force is a volumic centripetal force). Consider a cube ...
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1answer
48 views
Isolating vibrations originating from my machine
I'm developing a machine with a reciprocating motion (mass: 50-100 kg, period: 1.35 s, accelerations: 1 g). This machine is part of a process line, and I don't want the resulting "shaking" to ...
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1answer
56 views
Why does the fulcrum pin of a band brake experience “double” shear stress [closed]
My machine design textbook states that the fulcrum pin of a band brake during braking is subjected to a double shear. How do you say it is subjected to a double shear and not to a single one.
By ...
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0answers
29 views
Designing a Safe and Crush-proof Pokemon playing card box using a 3D Super-Elipsoid
My friend has two young Pokemon-addicted sons who carry their 60-card playing decks with them everywhere, typically in a cargo pants pocket. Unfortunately, they have either managed to destroy every ...
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4answers
206 views
Is there any link between tensile strength and endurance limit for steel ?
I'm designing a shaft, and i have to choose a material.
I deal with cyclic stress in my machine, so i set up an expression for all the possible stresses and combined it with von Mises criteria for ...
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1answer
83 views
Using strain energy to calculate deflection
I have a solids problem I cannot solve, I have the answer and I have attempted the question. I just need to know where I am going off track, (perhaps there was an issue setting up my deflection ...
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2answers
58 views
Stresses in a camera mount
I'm building a mount for a small IR sensor which will look very similar to this, minus the large camera.
I am wondering whether or not it would be necessary to do calculations to ensure that the ...
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2answers
66 views
Stress yield of a specimen, result confusion
I am trying to calculate the static yield stress of a specimen using the
0.2% offset line on a stress strain curve. I found the static yield stress of the specimen to be the number in bold (104.1239). ...
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0answers
39 views
Calculating the Structural Forces Required to Support a Robot on an Overhanging Beam
this is my first time posting on here and I have a question regarding the structural properties a beam will need in order to fulfill some requirements we have for our robotics team. The scenario is as ...
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1answer
70 views
Determining σxx on a 3d system with resolved forces (stress, strain, shear strain energy)
I am having trouble conceptualizing this problem. I have attempted it but am confused about a few things, I would highly appreciate any insight or advice for this.
I know you need to resolve P into ...
3
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1answer
120 views
Caulculating maximum shear stress at certain points
I have a structures problem I cannot solve, I have the answer and I have attempted the question. I just need to know where I am going off track. Any assistance would be highly appreciated.
My work is ...
3
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1answer
67 views
How to determine tensile strength while the normalised tensile strength is known?
I try to design a shaft with yet unknown diameter, i know the distribution of forces and stresses (shear, torsion and normal) in/ along the shaft. I need just one more parameter nl. the tensile ...
2
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1answer
61 views
What is the difference “maximum” shear stress and shear stress
Shear stress is introduced in statics as $\frac{P}{A}$.
However, the maximum shear stress with neutral axis is different. It is $\frac{3P}{2bh}$ (Where $b$ is width and $h$ is height)
What is the ...
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0answers
35 views
Equations for stress in a hollow prolate spheroid under external pressure
Are there analytical expressions (functions of geometry and applied pressure) for the stress in a hollow prolate spheroid, like there are expressions for the stress in a hollow sphere/cylinder?
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0answers
15 views
Consistent length in beam theories
From my understanding, the Euler Bernoulli Beam theory is mostly used for small angle displacements, and an implication of this assumption is that the length of the beam is subject to distortion and ...
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4answers
518 views
What is the difference between tau = VQ/It and tau = V/A?
What is the difference between the formulas $\tau = VQ/It$ and $\tau = V/A$ for finding shear stress due to transverse loading? I understand that the use of first moment of area, is the only reason ...
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1answer
28 views
How to apply static failure criteria for bending stress in an angled cylindrical surface?
Let’s say I have an irregularly shaped bearing with a cross section that looks like the angled surface of a conical frustum, shown below.
If a bending moment is applied which causes the inside ...
3
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1answer
67 views
Failure due to shear stress on rod lip?
Let’s say I have a circular rod that has an outside lip with a larger diameter and certain height. The rod moves axially, and the intent of the lip is to mechanically stop the rod at a maximum axial ...
5
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1answer
80 views
Would a partial space elevator work? [closed]
Background
The normal space elevator (that reaches from the Earth's surface to a counterweight beyond geostationary) needs a material that's strength/weight ratio is better than any material we have ...
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0answers
44 views
Normal stress - shear stress pairs not lying on Mohrs' Circles
The three Mohr's circles depict all the possible normal stress / shear stress combinations when material is taken and rotated along one of it's axes of principal stress. Nevertheless, it is clear that ...
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1answer
97 views
Do outer fillets|chamfers also reduce stress as inner ones do?
I kind of have an intuition or at least imagination about how fillet|chamfer of inner edges|vertexes reduce stress (concentration).
But does that apply to outer edges|vertexes aswell? Maybe to a ...
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2answers
18 views
How much ballast is required in 110 mph winds to stabilize: a 60 lb., 20’ pole; 3' below ground/17’ above ground, with a 24lb. wind turbine atop it?
I can’t seem to find an answer that doesn’t involve more than a ton and a half of concrete. The manual for the wind turbine reports that the load on the turbine in a 110 mph wind is only 155 ...
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1answer
55 views
Maximum Normal Stress From Mohr's Circle
Given This Diagram, I am to:
Determine Principal Stresses
(My Ans: 92000 and -8500kPa confirmed with Answer Key)
Determine Max Shear
(My Ans: 50500 kPa confirmed with Answer Key)
Find the Angle ...
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0answers
48 views
Plate bending boundary conditions
A plate with length 2L is placed on supports at x = L/2 and x = - L/2. The plate is deforming elastically under its own weight (maximum displacement bowing up at x = $0$). Both ends of the plate are ...
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0answers
133 views
Shear stress due to shear force in trapezoidal crosssection
I have a trapezoidal crosssection with a shear force applied at its top, like in this picture:
I know want to calculate the static moment, shear flow and shear stress of the crosssection. Given are ...
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3answers
78 views
what's the max stress value ?
in stress concentrations, say in a hole made in a beam loaded axially, we need the value of K ( the stress concentration value) which equals max stress\ avg stress for the given body.
the avg stress ...
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1answer
170 views
What's the difference between critical load and yield stress, and failure in general?
So far, I have learned of three quantities that are related to the failure of a beam (axial and longitudinal loads). The first illustrates the stress under which balsa wood will undergo plastic ...
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1answer
59 views
Most efficient fillet design given an envelope (for stress)
If one has a specified allowed X length and Y height, into which a fillet can be placed to reduce stress concentrations, is there an equation which can be used to determine the optimal shape of the ...
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0answers
25 views
Shear stress derivative in polar/cylindrical coordinates
I have an embarrassing question that I just can't seem to figure out. I have a fracture problem that is infinitely easier to solve in cylindrical coordinates. The boundary conditions, however, are ...
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0answers
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Calculating stress from elementary tension and bending formulas
I need help with this problem.
Suppose we have a cantilever with width $-c \leq y \leq c$ and length $x=l$ fixed at $x=0$. We know that it is loaded by uniform shear along the lower edge with ...
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2answers
52 views
Stress-resistant, elastic materials
I am currently looking for materials, which return into their relaxed form/ position after intense bending/ stretching.
Could you please let me know what is the name of this mechanical property, so ...
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0answers
45 views
How can I estimate the impact force of multiple objects falling at the same time from a given height?
I'm trying to model what impact forces a structure endures from multiple cylinders falling on it at the same time. I know the approximate geometry and density of the individual cylinders. I also know ...
2
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2answers
91 views
Computing strain in beams
I am studying this problem:
The rigid bar ABC shown in Fig. P-212 is hinged at A and supported by a steel rod at B.
Determine the largest load P that can be applied at C if the stress in the ...
