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Questions tagged [stresses]

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6 votes
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How to calculate the adhesion I need to keep a 3D printed bending part straight?

3D printed parts cool down during printing, resulting in thermal contraction which causes a bending moment and separation from the printing bed. The issue is solved by increasing adhesion to the ...
FarO's user avatar
  • 179
6 votes
0 answers
148 views

Calculating the bending moment ($M$) of a beam as it relates to stress ($σ$) and strain ($ε$)?

I am trying to learn how to work out the bending moment for progressively complex systems to model a beam. I am assuming only one axis of motion (transverse = $y$). For the basic equation of material ...
mike's user avatar
  • 161
4 votes
0 answers
84 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 ...
BobC's user avatar
  • 141
3 votes
4 answers
169 views

The behavior of the stress-strain curve of metal, containing a void

Let's assume that in a metal sample without any dislocation, there is a void. Then we conduct a uniaxial tensile test.
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3 votes
0 answers
316 views

Is having a keyway in aluminium for 30Nm a bad idea?

I'm designing an aluminium shaft hub for a 16mm keyed shaft with a maximum torque of 30Nm. However, stress analysis tells me that the keyway can suffer too much stress: If my understanding is correct,...
Kar's user avatar
  • 351
3 votes
0 answers
522 views

Why do we use the strain-controlled test for the compressive strength of concrete?

As you all now, a typical stress-strain curve for concrete under compression can be seen in any reinforced concrete design textbook. The decreasing part of the curve (post-peak) can be obtained by ...
alpos2801's user avatar
3 votes
0 answers
106 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 ...
Bruno KM's user avatar
  • 131
2 votes
0 answers
40 views

How do you estimate the energy of an impact?

I am trying to determine the energy of elastic stress waves generated in a solid by an impact. I have a time domain waveform from a piezoelectric transducer that was placed next to the impact site, as ...
Vishnu Venkatesh's user avatar
2 votes
0 answers
130 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 ...
DemonLordKing's user avatar
2 votes
0 answers
42 views

Unexpected stress concentration results

I've run some stress simulations but I keep getting some unexpected results. I have 3 parts connected using 4 bolts as follows: A torque of 1N is applied to the hole on the right to simulate a hung ...
John M.'s user avatar
  • 1,033
2 votes
0 answers
686 views

Double Shear Stress butt joint

A double shear butt joint is shown below in the diagram 4 plates are held together by two bolts. The applied force is 42KN. Determine the shear stress within the joint $$\begin{align} a &= 2 \...
Kyle Anderson's user avatar
2 votes
1 answer
169 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 ...
user1814893's user avatar
2 votes
0 answers
618 views

Impact force with unknown deformations or time duration?

I expected to find more documentation on analytical solutions to determine the contact force between bodies, where deformations ($\delta = \delta_{1} + \delta_{2}$) and impact time ($t = t_{f} - t_{i}$...
OnStrike's user avatar
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2 votes
0 answers
67 views

What is the load response of a threaded fastener?

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? ...
Mark's user avatar
  • 5,333
2 votes
0 answers
563 views

What is the longest self support length a chain one molecule wide can be?

Self-support length is the maximum length of a vertical column of the material (assuming a fixed cross-section) that could suspend its own weight when supported only at the top this is an important ...
James Jenkins's user avatar
1 vote
1 answer
63 views

Wind Pressure on Chimney

I have this question that I am trying to solve. I cannot put diagram up to show problem because it is over file size limit of 2 MegaBytes, but I will explain problem as best as I can. A brick chimney ...
Rob Wilkinson's user avatar
1 vote
0 answers
34 views

Optimizing the layer lines of a 3d printed part, based on subjected forces

I was directed here from the 3d printing stackexchange... For years I have been fortunate to only have had to make 3D prints that don't require a large amount of force on them. But recently (since ...
nick carraway's user avatar
1 vote
1 answer
109 views

Why does the torsion in a circular bar result in shear stress along the axial direction?

In the case of pure torsion, how does a differential area on cross-section of the cylinder with dx length undergo a shear force that is perpendicular to the cross-section ? I can understand that a ...
raconteur's user avatar
1 vote
0 answers
41 views

Why are these food stretch films (LLDPE) holding one one-thousandth of the weight in reality than what is expected from the datasheet values?

I am trying to reproduce analytically the results found in this experiment where a weight of 3 x 5 lbs (6,8 kgs total) breaks the cling wrap (LLDPE) which is stretched over a medium size cooking pot. ...
ChewingGumXpert's user avatar
1 vote
2 answers
202 views

How to solve this complicated truss system?

Below is a truss I simulated in a truss calculator. I'm just wondering, how to solve for the compression and tension of each member and are there any method that can solve this? My solution is I ...
Jasmine Su's user avatar
1 vote
1 answer
3k views

How do I calculate the strength of a carbon fiber tube?

I am not a mech engineer and have been struggling with this for a while, I feel like it is pretty straight forward but I'm missing something. The problem is a horizontal tube that is supported at one ...
Joshua von Damm's user avatar
1 vote
0 answers
33 views

Why doesn't the Stress Power in the theorem of the expended mechanical power contribute to the kinetic energy?

The following is the formula of the expended mechanical power: $P(t)$ $=$ $\frac{d}{dt}$ $\int \frac{1}{2} \rho\ v^2 dV$ $+$ $\int \sigma \colon d\ dV$ where $P(t)$ is the mechanical power entering ...
user134613's user avatar
1 vote
0 answers
190 views

What are the limits of small 3D printed gears?

How much tangential force should I expect a 10~20mm pitch diameter/1.5mm gear module 3D printed rack and pinion system to support without breaking nor sliding?
curioso's user avatar
  • 31
1 vote
0 answers
230 views

Is Viscosity = Slope?

studying fluid mechanics, I see that viscosity relates shear stress to shear rate, like a slope. However, on graphs I see that they draw a triangle, and where I would expect to see $\Delta \tau $, I ...
RMS's user avatar
  • 275
1 vote
0 answers
34 views

Should I use ST or LT values for extruded rod?

In MMPDS for AA7075-73511 (extruded rod) the Table 3.7.10.0(g3) show both ST and LT values for transverse directions. For a rod with circular cross section there is really no Short and Long transverse ...
David Lindberg's user avatar
1 vote
0 answers
27 views

Limit state design/ LRFD of short steel columns

Why do we use the yield strength as the limiting strength in short column design when using limit state design. Why is the full capacity of the material not utilized (as is the case with beams when we ...
Structural Enthusiastic's user avatar
1 vote
0 answers
813 views

Shear and normal stress in rivets

Hello everyone :) This is my first post here so please excuse any of my mistakes. I’m having some difficulty with solving the following problem. Let us have a thin-walled square pipe exposed to ...
EngineerInProgress's user avatar
1 vote
1 answer
249 views

Analytical solution of thermal stress in a bi-metallic cylinder

As a side project I have looked to solve using Python an analytical solution for one-dimensional transient heat transfer in a thick cylinder with cladding on the inside surface, wherein the fluid in ...
DMC05's user avatar
  • 11
1 vote
0 answers
26 views

WEC linear inputs

I have seen some designs being made for linear generators for WEC(wave energy) applications. A buoy driving a shaft. But what if the shaft inside was a rack and pinion? If you converted the ...
Ryan Griffith's user avatar
1 vote
1 answer
322 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 ...
S. Rotos's user avatar
  • 2,259
1 vote
0 answers
49 views

What is the difference between $K$ ,$K_{IC}$ and $K_t$?

I have seen three representation of stress concentration factor values $K$,$K_{IC}$ and $K_t$ now all that I know is $_I$ in suffix represents opening mode of crack.The suffix $t$ stands for tip....
user586228's user avatar
1 vote
0 answers
114 views

Shouldn't brittle materials be the ones failing under shear deformations?

It is known that brittle materials tend to fail under normal stresses, that is, tensile or compressive stresses. Brittle materials often are bound together into crystals by ionic bonds between atoms, ...
S. Rotos's user avatar
  • 2,259
1 vote
0 answers
1k 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{...
user19001's user avatar
1 vote
0 answers
74 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?
user3408085's user avatar
1 vote
0 answers
47 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 ...
Zihan Shen's user avatar
1 vote
0 answers
79 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 ...
Jonah Rolfness's user avatar
1 vote
0 answers
137 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?
user14783's user avatar
1 vote
0 answers
24 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 ...
Chang Hexiang's user avatar
1 vote
0 answers
125 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 ...
anarchoNobody's user avatar
1 vote
0 answers
103 views

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 ...
David's user avatar
  • 11
1 vote
0 answers
499 views

Will drilling a hole in a pane of glass reduce it's structural integrity?

I've got a glass box that measures 900mm x 450mm x 450mm. The width of the glass is 6mm thick. If I drill, cut, or grind a small hole in/through one of the faces; will it significantly affect the ...
voices's user avatar
  • 201
1 vote
0 answers
2k views

How to calculate effective strain in plane stress?

What is the correct formula to calculate the effective strain under plane stress conditions? In plane stress it is assumed that the out of plane stresses are zero. The out of plane strains are not ...
1QuickQuestion's user avatar
1 vote
0 answers
230 views

Distribution of shear stress in beam bending

Beer, Johnston, and DeWolf's Mechanics of Materials includes the following image of the distribution of shear stresses in a bending beam: (Axes and load vector carried forward from Fig 6.1 in the text ...
ericksonla's user avatar
1 vote
1 answer
589 views

Thermal expansion of a hole in a plate with a temperature gradient

I have a rectangular metal plate with a hole in it (with diameter of 300 mm). The plate has a temperature gradient going from one of its short sides to the other, I can measure the temperature ...
Ricardo Magallanes's user avatar
0 votes
0 answers
12 views

COMSOL multipysics - thermal stress for cubeSat in low earth orbit eigenvalue slover error

I'm using COMSOL version 6.2 for my simulation work. I'm dealing with Heat Transfer involving Radiation and Thermal Stress in solids phisics only after inserting all the constants and boundry ...
Abo Ayman's user avatar
0 votes
1 answer
21 views

Shaft undergoes torsion and centrifugal stress

I use this model to get the tangential and radial stress formulas but I want to examine a system also undergoes a torsion under constant speed. I'm a little confused at this point, do I need to point ...
Enes's user avatar
  • 1
0 votes
0 answers
26 views

What would be a good way to connect parts that would be replaced on a training model?

I'm trying to work on a training model for neurosurgery. Residents will be operating on the posterior part of the model, and it needs to be replaced after each training session. While the anterior ...
Bilal Bahadır Akbulut's user avatar
0 votes
0 answers
14 views

Mat Footing (Bending Moment Issue of the Short Strip)

Hi I'm a civil engineering student, I wanted to ask for help and clarification for the design of mat footing. I used the Rigid method and based my design on the ACI 336_2R and Foundation Engineering ...
CivilWorkz's user avatar
0 votes
0 answers
12 views

Addressing Variations in Stress Levels for Accurate Fatigue Analysis of Crankshafts

In analyzing the fatigue resistance of a crankshaft, how should we account for the variation in stress levels throughout its 360-degree revolution? Given that the crankshaft is subjected to different ...
amirhosein majidi's user avatar
0 votes
0 answers
15 views

Find stresses involved and calculate magnitudes

I am new to mechanical design.What all forces and moments act on the hinge plate in following figure?How to find magnitude of stresses induced on the supports? Note: The spring is an expansion spring ...
Bumane's user avatar
  • 1