Questions tagged [stresses]
The stresses tag has no usage guidance.
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1answer
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Finding Stress Concentration Factor when (D/d) ratio is not on a table?
So we have this homework problem, it is a rectangular filleted bar and we have to find the minimum thickness. I go and calculated the ratios but here's the problem: (D/d) = 1.375. What may the problem ...
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0answers
17 views
How do I find deflection and strain energy in this case?
How is the load transferred to the rocker beam? How do I find the deflection if the joint is a flexible joint?
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0answers
17 views
How can I increase the strength of this clutch without shearing my bushings?
Here's the setup:
(C) is a clutch. Beyond (C) is the source of torque. The belt (D) transfers the motion from the clutch to the sprocket (B). (B) then transfers the motion to (A) by way of 9 ...
0
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1answer
26 views
hoop stress on a thin glass window
A common problem with ultra-high vacuum viewport windows is that often the window material deforms, into a saddle or Pringles chip shape. .
An engineer from a viewport manufacturer explained to me ...
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1answer
49 views
Mechanics of Solids / Strength of Materials
I have shared a question from mechanics of solids and my solution with it, as you can see I am trying to take the derivative of the stress equations to find the min, max points but its going wrong. I ...
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0answers
29 views
Derivation of Bimetallic Strip Stress in Roark's Formulas
I am trying to understand some analytic expressions given in the handbook Roark's Formulas for Stress and Strain for bimetallic strip stresses. Namely, Roark's Formulas give the formulas
$$\text{...
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1answer
38 views
stress in X- and Y-direction
A steel parallelepiped with a square cross-section fits exactly into the cavity.
it's loaded from the top surface(see picture).
how can I calculate the stress in X- and Y-direction if the strain in X- ...
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1answer
34 views
Does tunnel lining made of cast iron tubings actually accept all the mechanical loads?
Here goes a recently opened underground railway station in Moscow, Russian Federation (image is from here)
On the left is an undecorated (just painted and it will likely remain this way) tunnel wall. ...
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4answers
71 views
Is youngs modulus a derivative of stress and strain?
From This page it can be seen that young's modulus is given by,
E = (Δstress) / (Δstrain)
Which means E is a point function, that changes as the strain in member is increased.
I am feeling ...
3
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4answers
74 views
How does stiffness/rigidity affect the bending moment of a beam
My question may sound silly as it’s mainly good sense but I may be mixing things up.
Let’s consider a flexible cantilever beam of a given length and material is fixed at one end and free at the other ...
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1answer
23 views
addition of non paralle shearing forces and stresses
I would like to ask for help regarding the summation of non parallel shearing forces acting on an elastic body.
In the image force F (Left to right direction,in yellow) acts on the top horizontal ...
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1answer
54 views
stress/shear analysis of components
I am working on analyzing a few problems, but have not really come across this type of stress concentration problem. Does anyone know where I can study the analysis of this situation?
Pressing ball ...
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1answer
38 views
Stress Tensor decomposition into Compression & Tensile forces
I'm working on a project that does a finite element simulation of a mesh. I can output the stress tensor at each node, but I'm not so sure how to implement failure criteria.
If my material is brittle,...
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2answers
35 views
How to calculate stress in a cylindrical-uniaxial-loaded bar with sudden changes in its diameter
How can I calculate the von Mises stress in the cross-section of a bar like this that is axially loaded?
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1answer
59 views
Is it possible to calculate Young's Modulus of Clay from load-controlled tests?
I'm trying to get the compressive strength (and Young's modulus) of a clay sample.
The method I found is called 'Unconfined Compressive Strength of Cohesive Soil'. According to ASTM D2166M, I have ...
2
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1answer
24 views
Normalizing the compressive stress to a cylinder
I'm not an engineer but a neuroscientist.
I do research in spinal cord injury whereby a clip is used to clamp the spinal cord to induce a bilateral compression injury model.
My research looks at the ...
2
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1answer
47 views
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
51 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 ...
0
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1answer
77 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
62 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
16 views
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
38 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
49 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 ...
1
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1answer
41 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 ...
2
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2answers
169 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?
1
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1answer
62 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
78 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
51 views
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
64 views
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 ...
1
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1answer
32 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
$$
I want to find the principle stress tensor $\sigma_{ij}^{pr}$.
...
1
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1answer
51 views
Base Support for a Tree house
I am building a tree house in my backyard and it is going to be relatively simple. There are no parts that require drilling into the tree. The whole house is propped up by four 4x4 wood supports. I'm ...
2
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1answer
39 views
What is symmetric?
What is symmetric?Please explain geometrically and in terms of displacements. I have encountered this while looking up for engineering strain and true strain values have totally different compression ...
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1answer
49 views
2-D Plane Stress Transformations
My strength of materials book provides the following equation to determine the x-component of the normal stress acting on all possible planes of a two dimensional element.
$$
\sigma_{x^{\prime}} = \...
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0answers
22 views
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
49 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 ...
0
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1answer
88 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
51 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
575 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 ...
0
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1answer
145 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 ...
0
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2answers
59 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
67 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
50 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 ...
2
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1answer
106 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
153 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 ...
4
votes
2answers
105 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
votes
1answer
83 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
40 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
16 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
1k 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 ...
4
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1answer
33 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 ...
