Questions tagged [solid-mechanics]
265 questions
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Interpretation of Lamé’s parameters in solid mechanics
I think I have a pretty good understanding of the physical interpretation of Young's modulus $E$ and Poisson’s ratio $\nu$ in solid mechanics. However, I often find in mathematical papers that the equations are formulated in terms of Lamé's 1st and…
Paul
- 683
3
votes
1 answer
Can a material generally score or cut itself by hand?
I'm wondering if a given solid material can, in general, score or cut the same material, when applied by (at most) human muscular strength.
I've tried searching for this online, but it seems like a difficult-to-express search target. For example,…
3
votes
1 answer
How to interpret the constraints on Poisson's ratio values, physically?
If I'm not mistaken, a Young's modulus $E$ can theoretically take on any positive value without bound. Physically, I interpret this as though a solid can have any arbitrary "stiffness" (within the limits of its linear stress-strain region, of…
Paul
- 683
2
votes
0 answers
Simple model of fiber interaction for pressurized braided tubes
I am trying the understand the failure modes of braided tubes containing high pressure gas. Here is an example of such a braid with a variable radius:
The tubes have an internal liner for sealing purposes, but nearly all stiffness (pressure…
Geoffrey Irving
- 213
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1 answer
What is the spatial derivative of strain tensor?
I'm looking for a metric that contains enough information of a 3D solid's deformation: stretch, bend and twist, etc. Stretch, bend and twist may be ambiguous for a 3D solid, since unlike a rod, it doesn't have a curve direction. Let's assume that…
Fei Zhu
- 363
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2
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1 answer
Why are rebar grooved?
Just what the title states, please.
Iron reinforcement bars used to provide the framework over which concrete solidifies always appear to bear grooves. Do the grooves behave as the thread of a screw and provide better grip? Are the grooves merely a…
Everyone
- 4,703
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votes
2 answers
How to formulate pin joints in finite element modeling of solid frames
In frame analysis with finite element every node can be assumed with 6 Degree of Freedom (3 translation DoF and 3 rotational DoF). There are formulations over the web for creating stiffness matrix etc. of frame elements like this one. These…
epsi1on
- 123
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vote
1 answer
Infinite deflection on axially compressed beam
With $k$ proportional to the square root of the compression force, an axially loaded (and otherwise unloaded) beam has a deflection following the DE
$$
\frac{\partial^4}{\partial x^4}z + k^2\frac{\partial^2}{\partial x^2}z = 0
$$
With solutions on…
user877329
- 115
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vote
2 answers
Deflection in beams -- which material properties are most influential?
I am modeling a beam made of an orthotropic material. The beam's length is aligned with the x-direction, and the force is applied in the y-direction (it is a 4 point bend experiment that I am modeling), along the thickness of the beam.
Intuition…
anonuser01
- 175
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vote
1 answer
Taylor series expansion for stresses on an element vs equal stress values on opposite faces
I only recently realized this "confusion" despite having cleared all my exams long ago. Consider these 2 diagrams:
and 2.
Clearly they yield different equations. I have seen both in different sources, but cant reconcile them since in both…
rrkkass
- 75
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vote
1 answer
How do you compute the stiffness tensor for anisotropic linear elasticity?
The stiffness tensor for anisotropic linear elasticity stiffness tensor consists of 36 elements, but only 21 are unique.
Are there equations for these elements as a function of the material properties elastic modulus and poisson's ratio? If so, I…
user27504
- 117
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vote
2 answers
Relationship between Young's modulus and Bulk modulus
I recently came across a statement in a publication "The Young's modulus and Bulk modulus are independent of each other for a uniform isotropic material".
Is this valid considering the two are related in terms of Poisson's ratio?
Ls Staley
- 11
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vote
0 answers
Diameter cutting x Center mass
I'm trying to set the ratio between the variation of the diameter cutting in the region lower a sphere with respect to distance from the center of mass with the center of the radius of the sphere.
For example, if the diameter is zero the center of…
LCarvalho
- 111
1
vote
1 answer
Do pipes only expand lengthwise when heated?
Pipe Stress engineers seem to only be concerened with lengthwise expansion. Why is this?
When something expands due to temperature increase, does poisson's ratio apply? Or is poisson's ratio only due to an external force being applied?
Mike K
- 36
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1 answer
Does 'maximum principal stress fracture criteria' only apply in tensile loading?
I'm working on 3d simulation of solid fracture, primarily for graphics applications. I have one question about the Rankine fracture criteria, which is widely used in the computer graphics community.
The maximum principal stress fracture criteria,…
Fei Zhu
- 363
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