Questions tagged [solid-mechanics]
Solid mechanics deals with the solid bodies subjected to various type of loading and internal forces generated due to this loading.
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What is the difference between maximum principal strain and maximum in-plane principal strain?
For the purpose of answering/explaining this, it does not need to be restricted to strains (i.e., it can be stresses too). I am mainly trying to understand when to use which one (i.e., if I am ...
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Honeycomb structures vs shear stress
Honeycomb structures are made of top and bottom shells and honeycomb geometry at core. In terms of bending load, maximun normal strains take place on top and bottom hence, sheet parts can support them ...
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Relationship between shear moduli in an orthotropic material
I'm confused what the relationship between each of the shear moduli are in an orthotropic material. From what I understand, there are 3 independant major shear moduli, G12, G13, and G23. They each ...
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What is the meaning of the traction continuity condition in the generalized momentum balance (continuum mechanics)?
In Nonlinear Finite Elements for Continua and Structures by Belytschko and al. it is stated:
As we have already noted, the strong form, or generalized momentum balance, consists of the momentum ...
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Rationale For Plain Strain Assumption in Long or Infinite Bars
When plane strain is discussed, there are two examples given, both of which involve two dimensional boundary stress conditions. One is a constrained object that cannot move along the third axis. From ...
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Vertically oriented shaft sleeve rubbing against bearing - Calculating side load due to a certain amount of tilt
At some given angle of tilt, we will perceive the pressing of a rotating SS shaft sleeve against a greased bronze journal bearing. How would you compute the side load force on the bottommost bearing ...
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In FEM, what is the difference between a single element with a quadratic shape function and two elements with linear shape functions?
Using Finite Element Analysis to obtain a Weak form of a PDE, what is the difference between the two cases:
A single element with a quadratic shape function
Two elements with linear shape functions.
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Specific Heat, Pore Fluid In ABAQUS
I want to model a problem that the theory behind is in the "Coupled Pore Fluid Flow and Stress Analysis" context that there is in the ABAQUS online documentation, version 2022. The link to ...
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Mechanics of Materials Method for Curved Beam with Different Centers
The common curved beam theory covered is the Winkler method (e.g. in Johnston and Beer, or Boresi and Schmidt). As can be seen by reading any derivation, this method applies to beams with a common ...
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Error while using VWRITE command in ANSYS APDL
I am writing code in APDL for a nonlinear structural analysis of a plate.
Following is the Post processing part which returns a formatting error. Help will be appreciated in identifying the problem ...
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Moment at the end of the shaft, after a bearing?
I have an application with an interchangeable load. That can be swapped in a machine.
The bearing and break are both mounted to different sides of the same plate
The load is placed on two shafts that ...
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Understanding forces acting on solids
I've just started learning about axial stresses on solids, primarily soil samples and this is the first time I've encountered proper forces on solids, and we consider this over an area, previously I ...
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Does gold have elastic behavior?
I know structural steel is considered to have an elastic behavior and after a certain deformation, it has a plastic behavior.
How about gold metal?
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How do I properly scale down a force for scale-down model testing?
I am designing structural frame for a shipping container that would have 8000 lbs of weight stacked on top of it. Of course, i don't access to real size container. I have built a model whose scale is ...
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Problems in the application of the first theorem of Castigliano for a cantilever beam
I'm having contradictory results while applying the first theorem of Castigliano for the cantilever beam shown in the figure above. Due to P and the restrictions on point $B$, it will have a bending ...
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how to determine the direction of support reactions in a truss?
Hi, I am not sure how to determine the direction of support reactions at point A and K. I know point A has a pin support, therefore, it can take in horizontal and vertical loads and point K has a ...
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How to find Tensile Modulus of a layer of Plain Woven GFRP with GSM of Fabric given
I need to Input "E" the tensile modulus for analysis of a composite layer made from Plain Woven E-Glass Epoxy composite material.
I know the GSM (g/m^2) of fabric is 106.
Using GSM =106, ...
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How to calculate failure stress on a hollow pin loaded in shear
Calculating limit stress on a solid pin loaded in shear is straightforward, and there are several handy calculators which will do single shear and even double shear. However, everything I have found ...
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Which design is most resistant to tipping against 90 degree downward force?
Have a question sort of related to question at (What calculation to find how much force before tipping over?) but with slight modifications.
Trying to weld some tubing together and onto a heavier base ...
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What is the steel used for CHC DIN912 class 12.9 exagonal bolt?
I would like to know which steel is used for CHC class 12.9 bolt DIN912 (i am looking for the young modulous & poisson ratio of the material).
Thanks a lot.
Alexandre
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Can the general Flexural formula be used in the case of transverse loading of a beam?
The general derivation of the Flexural formula uses the pure bending case, where the distance from a curved section to the neutral axis is assumed to be constant even after bending, denoted by y. The ...
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how to find the tension matrix knowing the extensions
At a point $ P $ on the surface of a body, the rosette of 45 gauges indicated in the Figure is glued, whose readings are $\varepsilon_1 = 2 \times 10^{-6}$ , $\varepsilon_2 = 1 \times 10^{-6}$ e $\...
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Building Equations of Motion
The following figures represent a model of a building, can someone help me, extract the newton equations of motion and determine the degrees of freedom.
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Why is there a negative sign in case of moments caused by longitudinal stresses?
I came across the following relations in the plate theory. I, however, don’t understand the reason for the negative signs in Mx and My. There is, however, no negative sign in Mxy. I am guessing, this ...
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Plane strain delamination on bilayer material (conversion from material stress state to residual force and moment)
I have been reading the book The Mechanics and Reliability of Films, Multilayers and Coatings (https://doi.org/10.1017/9781316443606) on chapter 4.2 and got stuck in chapter 4.2 and 4.3.
Suppose that ...
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Is the a similar method of calculating moment in inelastic bending like in the case of torque for inelastic torsion?
When calculating for Torque in torsion or for Moment in the case of bending, the concept is usually first introduced with the simplification of the assumption that the stresses and strains are in the ...
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How do bearing companies calculate their bearing's dynamic load rating?
I can find L10 and L50 life of bearings on the bearing catalog and use that to find the life of bearing for a certain load 'F'. But I can't really find any references on how these companies find ...
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Why are the indices of term of the Cauchy Stress Tensor and Maxwell Stress Tensor opposite to each other?
For CST (https://en.wikipedia.org/wiki/Cauchy_stress_tensor), the first index represents the plane and the second index represents the direction:
For MST (https://en.wikipedia.org/wiki/...
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Why do two simply supported beams stacked on top of each other deflect more than a single beam of twice the thickness?
If the thickness of each beam in the stacked configuration is 't', the thickness of the single beam is '2t'.
Explanations in terms of Euler Bernoulli beam theory, or any other explanation that is ...
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How to find the displacement at each interface of a composite structure subjected to shear force?
Imagine a block made of 3 horizontal layers of 3 different materials (shear moduli S1, S2, S3) and fixed at the bottom surface.
If I apply a displacement 'x1' (or shear stress 'V1') to the top layer, ...
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Which of these two cases will have the most friction?
I have a structure colored in blue which we are looking directly downwards on (birdsview). Its high up in the air, and the only thing keeping it from falling down is the friction surface (red) between ...
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Why is there a lack of data and analysis of elastic range of PTFE (Teflon)?
I am looking for the proportionality limit and elastic limit of PTFE (Teflon).
There are several papers which reported the mechanical behavior of PTFE in tensile test. However, almost all of those ...
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Optimal shape for cantilever beam subject to body weight only
How can I find the optimal shape of a cantilever beam subject only to its own weight, and having the following restrictions?
The cross section is a rectangle
Only the height of the rectangle can vary ...
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CNC a hemisphere in SolidWorks
Dear all, I am currently learning CNC Milling software. I have successfully be able to simulate the toolpath for milling a square block to a hemisphere. May I ask how to add another operation, that is ...
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Can stress be generalised to points?
I know we can talk about a 'stress' in an area for which a 'uniform' force acts, can we generalise this to the stress at each point in the area, by making smaller areas around a point such that:
Over ...
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How to find out the strain distribution of a block in a simple compression test?
I am performing a displacement-controlled compression test on a square block, where the top of the block is attached to a fixed plate, and the bottom of the block is attached to a movable plate that ...
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Thin wall pressure vessels: local stresses in bends
How can I calculate the stresses in corners where different geometries meet?
This image is a quick example of the positions i am referring to.
Additional information
In class we studied the membrane ...
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How to calculate press load for an interference fit with no friction coefficient between the materials (shaft & hub)
Press-fit load calculation always takes friction into consideration and gives you the load expression as follows,
$$F = µ\cdot PA$$
where µ is the friction coefficient, P (Interference Pressure) is ...
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Why carrom coins have the circular profiles on them?
Why do carrom coins have these circular profiles on them? At first I thought that this will reduce the friction as area reduces, but quickly recalled that friction for solids don't really depend that ...
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Thermal Expansion and Stress in a Heated Beam
Consider the case of a beam that is supported in such a way that expansion can occur freely. Suppose that the beam is heated in such a way that the temperature varies with the depth of the beam. Let $...
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How can I recover the deformation gradient from the finite element strain result
I have performed a finite element simulation which corresponds to the example in https://de.wikipedia.org/wiki/Deformationsgradient#Beispiel .
The result from the theory in wikipedia is the following (...
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Using Strain Tensors to Recover Stress Tensors
Disclaimer:
I am very new to the field of mechanics, my background is in electrical engineering. I apologize in advance if anything is horribly wrong.
My references are:
"First Course in FEM, 4th ...
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Potential Problems of Excessively Hard Shaft
Will there be any issues if we make the shaft too hard?
Hardness being a surface property may prevent surface scratches and wear, could it lead to any problems in general?
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Infinite life of a material, Fatigue Strength
After 10^6 cycles a component is considered to have infinite life. What makes 10^6 cycles a deciding factor for infinite life? Why not 10^8?
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In the context of Beam Deflections If the moment curve has a discontinuity, how do we account for it in the slope and deflection curve?
In reality if we load a beam within the elastic range of the material, it forms a curve that can be represented by a mathematical equation. But if the moment curve has a discontinuity it must mean ...
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Doubt related to S-N curve
S-N curve is drawn from the results of fatigue test and fatigue test is conducted under completely reversed bending stress condition on a standard specimen. Is there any reason for conducting the test ...
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Failure of component due to natural frequency vs stress
lets take a component like a fan blade as an example. Is it right to conclude that it will fail even when the stress is within permissible limits but its operating frequency is close (close enough ...
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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 ...
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Understanding Castigliano's First Theorem Proof
I'm trying to understand the derivation of Castigliano's first theorem in the book Fundamentals of Finite Element Analysis by David V. Hutton, which goes as follows.
The strain energy is defined as
$$...
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Why is it that plane stress varies?
Take the simplest example of some uniform bar being stressed by a force N, I understand that we need to adjust an angle to determine the stress in terms of shear and principal stresses on that plane, ...
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