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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32 views

What parameters are involved in sizing the structure subjected to a dynamic condition?

Consider the example shown below. The force applied is a follower force, meaning that it always is tangent to the application face. Body-Ground revolute joint below means that the face is able to ...
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3answers
53 views

How will the reaction moment on the support be distributed in terms of forces in this model?

Consider a rectangular cross sectional solid beam, fixed at one end and a uniform shear force applied to the other end. Below shows the side view for this beam. Now, I change the support area as ...
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Question about cam follower design

It's always said that jerk function should be smooth to avoid undesired vibrations. What exactly is the vibration in a cam follower mechanism and why is it important to avoid it?
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Is Smith Diagram and Modified Goodman Diagram the same? And how does one construct it?

I am confused about the names. Moreover, I haven't found any textbook which attempts to show step-by-step construction of these diagrams. I would be happy if anyone pointed to some textbooks or even ...
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What is meant by Solid Mesh and Surface Mesh? [closed]

Solid Mesh vs Surface Mesh, which method should I choose in simulation studies. What is the geometry behind these meshes. Which mesh gives accurate results?
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How many more degrees of tilt can the Millennium Tower in San Francisco withstand before it becomes structurally unsound? [closed]

How many more degrees of tilt can the Millennium Tower in San Francisco withstand before it becomes structurally compromised/unsound? "...An examination in 2016 showed the building had sunk 16 ...
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Difference between Stiffness (K) and Modulus of Elasticity (E)?

Stiffness (F=Kx) is the extent to which an object resists deformation in response to an applied force. Elastic Modulus (E=Stress/Strain) is a quantity that measures an object or substance's resistance ...
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Why does a jumping rope have no bending stiffness and compression stiffness?

Can anyone just tell me that why doesn't a jumping rope, or any other kind of rope, have any bending stiffness? If I hold one end of the rope in my hand, the rest of the rope will just fall. It won't ...
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Can we use the Flexural formula and the Beam theories for bodies made up of Composite materials?

Below shows a link for the derivation of Flexural formula. Derivation of Flexural formula In this above link, there are a few assumptions made to reach to its final form. They are shown below. By ...
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Bending stress wave resulting from a lateral impact on a beam

I want to approximate a bending stress wave resulting from a lateral impact on a beam which is on one end fixed. According to Roarks 16.3-3 I can estimate a compressive stress wave from one mass ...
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Holzapfel-Gasser-Ogden (HGO) model

Can Holzapfel-Gasser-Ogden (HGO) model be applied to solid porous materials such as rocks, concrete and etc. as well? If yes, would you please introduce a reference. If not, is there any modified ...
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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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Clad Cylinder Thermal Stress Analysis

How can one determine the thermal stress between the clad and the substrate on a clad cylinder? How can one determine the thermal stress on a clad plane? Can it be shown that if the radius is ...
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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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76 views

Beam with width tending to zero

Suppose a cantilever beam (of rectangular cross-section) subjected to vertical transverse shear load at free end. If I consider any arbitrary cross-section then both bending and shear stress will be ...
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Interpretation of dimensionless numbers as ratios of forces

How can the dimensionless numbers like reynolds number etc be interpreted as ratio of the various forces? The explanation given by most sources in this regard seems quite unsatisfactory and not much ...
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Should we use Hooke's Law (that linearly relates stresses to strains) if the stiffness of body is changing during deformation?

Assume I have a slender cantilever beam, fixed at one end and force applied on the other. Now, during the deformation, we know that the beam's stiffness is going to change and the force-displacement ...
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559 views

Why shouldn't we use Bernoulli beam theory if deformations and rotations are large?

I was going through the basic assumptions made by Bernoulli beam theory. I realized that one of the most important assumption in this theory is that the deformations and rotations of the beams are ...
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How to choose contravariant or covariant bases?

I completed an introductory course on continuum mechanics, but we did not delve into curvilinear coordinates with CM. However, when I read some publications I see the stress-strain relationship is ...
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Stress divergence of elastically deformed body is not zero

TL;DR According to the analytical solution (link) for a deflection of a cantilever beam $\sigma_{xx} = - \frac{P xy}{I}$, $\sigma_{yy} = 0$ and $\sigma_{xy} = -\frac{P}{2I}(\frac{D^2}{4} - y^2)$ and ...
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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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What is the difference between max shear stress at neutral axis in bending and max shear stress from Mohr's Circle?

The maximum shear stress which we get from the equation: $\frac{VQ}{It}$ (for instance, the maximum shear stress at the neutral axis for a rectangular beam cross section, fixed at one end and ...
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Strain gauge measurement using NI 9944

I am trying to measure the strain on a part using a strain gauge. The gauge is a 120 $\Omega$ strain gauge from HBM. I am using National Instruments (NI) hardware and LabVIEW software to capture the ...
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4answers
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Is bending moment along a beam independent of the cross sectional area of the beam?

We know this that if the a cantilever beam (of any cross section) is fixed at one end and a transverse force is applied on the other, then it will bend. However, we just casually assume that the ...
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Connection between strain energy density and energy due to a moment

Can the strain energy density (volumetric density) always be written as $\frac{1}{2}\sigma\varepsilon$ as long as the object is subject to just axial loads and moments (neglecting the work done by ...
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1answer
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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 am I seeing a moment reaction at the supports for these beams in FEM?

Please observe the Finite Element model below, in ANSYS WorkBench, (Remote force behavior = Deformable). Also, please take a lot at the force and moment reactions at the fixed supports. I couldn't ...
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1answer
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equivalent Hertzian contact pair for arbitrarily shaped bodies in 2D [closed]

I am a bit new to this field here. I am trying to determine the contact stress between two arbitrarily shaped bodies that are indenting into each other (see attached image). I would like to solve ...
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1answer
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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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Formation of robot links programmatically in Solidworks

Spherical Parallel Manipulator in SolidWorks My question is a continuation of the topic. Is it possible to form the links and joints of the robot not manually, but programmatically in Solidworks? For ...
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3answers
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Does lead screw's thread have to be trapezoidal?

I want to move a small tool table/bed linearly, so I'm designing its mechanism. Fairly simple, it's going to have 2 rails and a lead screw. Browsing the web I find that locally the shortest ...
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Does the Superposition principle actually make sense in reality for a rod subjected to bending and axial force togehter?

Consider a rectangular rod, for example. I fix it from one end and apply a transverse force on the other (to cause bending) and also a axial force (lets just assume its compressive). Now, according to ...
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Why is the theoretical formulation not explaining why the graph of the square of the velocity and angular displacement is nonlinear (experimentally)?

So I did a wind tunnel experiment where I put a rope restrained (1 degree of freedom, so it can wave in the direction of the wind) at one end so that it displaces according to the variation in wind ...
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2answers
136 views

Reaction forces on a three support continuous beam with two of them requiring compatibility equations. Superposition method done wrong!

I need to analyze a continuous beam of length L and three supports: A (at x=0), B (at x=L/2), and C (at x=L). An applied load P is applied at x=3L/4. Now, at A, the continuous beam is bolted to a ...
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torque for a machine shaft

this is a formula for torque and I was wondering for what P in this case stands for . . .
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1answer
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i need help regarding my project of animating a machine

I am designing a machine consisting of gears , four bar mechanisms and rollers but I need the reference of a software where I can draw or construct the instruments and components and execute the ...
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What is stress stiffening in Finite Element Analysis?

In a Finite Element Analysis, if we turn ON the geometric non-linearity, it also takes into account the stress stiffening if any structure is undergoing it. That is what I have read in the literature. ...
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Why do we always need to calculate the 'Moment of Inertia' about neutral axis for bending?

I was having a look at the bending stress derivation in few of the books. The derivation indicates how each of the element in the bending stress equation is derived into that equation. However, for ...
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Does numerical dissipation in FE simulations affect system's elastic energy? Does it depend on thickness?

I am running a finite-element simulation in Abaqus, for which I also have a theoretical model. To be precise, I am simulating wrinkling in a thin annular sheet, with shell elements. The model makes a ...
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Would poisson's ratio also result in stresses in lateral directions?

This is kind of like a basic question which students might ask in their bachelor's level of education, which I want to refresh my knowledge about. So if I apply a load in a single longitudinal ...
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Compute deformation response history from ground motion

I'm reading a book of Anil. K. CHOPRA related to Structural Dynamics, I'm intending to obtain the deformation response spectrum from given ground motion. What I have here in hand is ug(t) ground ...
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1answer
64 views

Spherical Parallel Manipulator in SolidWorks

I need a little help with SolidWorks. I need to assemble such a mechanism, which I am currently working on. But I get a rather complicated and cumbersome algorithm: First, I build a "wireframe&...
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1answer
35 views

Why is plastic deformation a non-linearity if I am using Bilinear hardening to model it in FEA?

Attached you may find a picture for isotropic bilinear hardening up until the ultimate tensile strength. The first line is the elastic region while the second one is plastic. I couldn't understand ...
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Why do we have two different Elastic Modulus in Tension and Torsion?

I was trying to get a value for elastic modulus for 316L stainless steel material from internet, and I saw a brochure online which was giving two different values for elastic modulus, one in tension ...
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2answers
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Which yield strength should I use in FEA in ANSYS; Engineering or True?

Attached is a figure to illustrate the difference in the value of yield strength as observed from the true stress/strain curve and engineering stress/strain curve. While conducting FEA in ANSYS for a ...
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What happens to load bearing capacity during the plastic region for a ductile material?

Attached is a picture of a typical isotropic ductile material. Can anyone please tell me what happens to the load bearing capacity in the structure in each of the sub-regions under plastic deformation,...
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Can we say that stress strain curve for a tensile test is function of strain rate and temperature?

I am currently studying about tensile test where it is saying that it is conducted at a constant strain rate. Also, it is said that it is conducted at a particular temperature. So can we say that ...
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Boundary condition at supported end of a rod

I have one end of a rod held in a hole of a 'rigid' part with no clearance, while the other end is loaded with a force. I have shown 3 simple reaction-force models in the picture. If my intent is to ...
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2answers
482 views

Calculating the von mises stress in a 3D beam when given stresses and moments on both ends

I want to calculate the von mises stress in a given structural member. I want to generate a von-mises plot from this data. The forces are according to the local coordinate system of the beam. Also, I ...
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1answer
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Neutral axis and 2nd moment of area [closed]

Does anyone know how I would find the horizontal neutral axis (yc) and 2nd moment of area of this cross section? (R = 210 mm) I know that and that there needs to be the same amount of area on either ...