Questions tagged [beam]
Questions about the theory and applications of structural elements designed to resist bending.
373
questions
0
votes
1
answer
13
views
understand clamped-mass modes and pinned-mass modes in frequency response of Euler-Bernoulli beam
The picture below shows the frequency response of the strain at the base (proximal end) of an Euler-Bernoulli beam, when actuated with random torque applied at the base (proximal end) from the paper: ...
- 101
0
votes
2
answers
408
views
Shear Force in Inclined Beam
Suppose I have an inclined beam with a UDL applied vertically downwards, will the shear force act normal to the beam, or vertically?
CommunityBot
- 1
0
votes
2
answers
99
views
Post and steel rope framework for grape vine
I am planning to build a framework to support a grape vine above a patio. Ideally I would like to use steel rope to provide this framework, rather than a full timber frame.
Diagram attached.
There is ...
CommunityBot
- 1
0
votes
1
answer
104
views
Calculate the deflection of a fixed supported beam
I am having a lot of trouble with the below question. Im not really sure how to calculate the deflection of the x coordinate, how do i go about completing this question?
Any help would be appreciated ...
CommunityBot
- 1
0
votes
1
answer
102
views
Calculating Admissible Shear stress with a uniformly distributed load and a point load
I have the following equation for calculating the Admissible shear stress for a uniformly distributed load.
$$\tau_{adm} = \frac{3}{2}\cdot \frac{F\cdot L}{2b\cdot h}$$
where
$F$ = kN/m
$L$ = ...
CommunityBot
- 1
0
votes
3
answers
178
views
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 ...
CommunityBot
- 1
0
votes
1
answer
105
views
Determine the temperature required for expanding or bending?
Is there any way to calculate the temperature required for a metal to expand or bend with dimensions?
For example, take Mild steel with a length of 100mm, width of 150mm, and thickness of 2.5mm.
I ...
- 204
8
votes
2
answers
1k
views
Design of transverse reinforcement in a wide beam
Besides satisfying nominal bar provision in the code, is there any special requirement in the provision of transverse reinforcement to ensure that the longitudinal reinforcement is fully effective in ...
CommunityBot
- 1
0
votes
1
answer
33
views
Bending in a wall due to deflection in the beam below
If I have a wall above an opening bearing on a beam that is simply-supported, will the deflection on the beam cause a bending effect on the wall if it is to rest on it? In order to match the shape of ...
- 8,222
0
votes
1
answer
51
views
understanding Euler-Bernoulli beam segment curvature distribution and external torque balance
For a cantilevered beam below using Euler-Bernoulli assumption, use $w(x,t)$ to denote the vertical displacement at position $x$ along the beam. At the clamped end, we have
$w(0, t)=0$ and $\frac{\...
- 22.6k
0
votes
1
answer
218
views
Boundary conditions for a cantilevered Timoshenko Beam
I am trying to find out the boundary conditions for above given Timoshenko beam. The boundary conditions that I have derived are
$x_1 = 0$
$$ \overline{u}_2^L = 0 $$
$$ \phi_3^L = 0 $$
$x_1 = \...
CommunityBot
- 1
1
vote
1
answer
219
views
Beam stiffness matrix with sliding end release in arbitrary angle
I know how to get the stiffness matrix of a beam with any type of end releases (hinges and rollers) by applying Guyan reduction (static condensation) to the beam stiffness matrix in local axes. ...
CommunityBot
- 1
0
votes
1
answer
77
views
Beam deflection for FEA model validation
I'm trying to validate an FE model that I'm using by comparing to a simplified analytical solution to the problem.
The part I'm analyzing is a lug that is constrained on one end and has a point load ...
CommunityBot
- 1
0
votes
2
answers
238
views
Composite Cantilever Beam Analysis
I'm trying to solve this composite cantilever beam for deflection analysis. How should I proceed? I'm not from mechanical background.
The connection between the elements is strong enough that the ...
CommunityBot
- 1
0
votes
1
answer
262
views
Linear Motion Stage with Offset Loading Problem
I'm currently developing a linear motion system which will have to withstand a large offset load (see image below). There will be two rails, each with a carriage on, which will be connected by a beam/...
CommunityBot
- 1
5
votes
2
answers
392
views
How to analyze a bent beam: Stress concentration?
I am analyzing a beam, that has a bend in it. Intuitively and inspecting FEA results using a linear solver, there is a stress concentration at the bend of this I-beam.
The part was not a straight I-...
CommunityBot
- 1
0
votes
1
answer
29
views
Searching for geometric modeller to investigate behaviour of beam when deflected
I have the scenario where I wish to model the movement of a simply supported beam under a central point load. I've done some stuff in R Studio to come up with deflection plots and that's fine. In ...
CommunityBot
- 1
1
vote
3
answers
144
views
How many support beams/rods needed for a firewood storage cabinet
I am building a firewood storage cabinet which should support around 100-150 kg of firewood.
The cabinet is made out of wooden boards (...
CommunityBot
- 1
0
votes
2
answers
39
views
Deriving an analytical solution for a bar under distributed torsion
Okay, so I'm considering the torsion model given by this figure:
I understand that the differential equation of such bar model is given as:
$$\frac{\text{d}}{\text{d}y}\left[G(y)J(y)\frac{\text{d}\...
CommunityBot
- 1
0
votes
1
answer
16
views
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 ...
CommunityBot
- 1
0
votes
1
answer
47
views
Rigid frame deflection and material selection
I'm building a frame that will receive a point load mid span (likely it won't be but want to design for worse case).
The frame is 1.5 x 0.095 square tubing, and it will be skinned with 14ga on one ...
CommunityBot
- 1
0
votes
1
answer
150
views
Modeling the Internal Forces Exerted on a Catapult Arm while Throwing
I am currently creating a MATLAB script to determine the internal forces present in a uniform beam as it is accelerated by a torsional spring. I was able to derive the equation for the axial force ...
CommunityBot
- 1
1
vote
2
answers
2k
views
Multiple varying cross section beam with uniform loads
I have the following cantilever beam problem where I need to find the deflection of the tip at P.
I tried to compute the deflection of the beam using Castignliano' s theorem as described in this ...
CommunityBot
- 1
0
votes
3
answers
2k
views
What's the best shape (solid of revolution) for a cantilever beam to carry a point load at the free end?
How should you change the diameter/radius (while keeping constant overall volume) of the cross-section along the length of a round cantilever beam so that you minimise deflection with concentrated ...
CommunityBot
- 1
1
vote
1
answer
114
views
Beam load - bending design value of southern GC yellow pine for treehouse beam span
I'm looking to build a treehouse and wanting to ensure the support beams can carry a sufficient load over an 11-ft span. Based on page 78 (aka 83) of https://awc.org/wp-content/uploads/2021/12/AWC-...
CommunityBot
- 1
1
vote
1
answer
171
views
Simple cantilever beam deflection - what is the simplest way to add a damper?
I am looking at a simple cantilever beam deflection:
I understand the general expression for deflection/force would be:
$$y_s = \frac{Fx_s^3}{3EI}$$
$$F_p = \frac{3y_sEI}{x_s^3}$$
If you were going ...
CommunityBot
- 1
1
vote
1
answer
232
views
Comparison of Shear Stress obtained from thin-walled beam theory and Timoshenko beam theory
I am studying the book "Structural Analysis with Applications to Aerospace Structures" by Craig. In Chapter 8 titled "Thin-Walled Beams", the authors derived the governing ...
CommunityBot
- 1
0
votes
2
answers
1k
views
Calculate shear and deflection for simply supported beam on different support height (like a staircase)?
I’m trying to calculate the beam deflection for an inclined beam. It’s only connected to floors (and not walls). The beam is a monorail, and I want to test different shapes (tubes and I-beams).
Plenty ...
CommunityBot
- 1
0
votes
1
answer
147
views
Determining the critical load of a fixed beam with non-uniform cross-section?
I am a computer scientist, not a mechanical engineer, so it is absolutely possible that I am missing some basic understanding here.
I have a beam that is fixed in both ends and my goal is to ...
CommunityBot
- 1
0
votes
2
answers
782
views
How is the limit state EQU used in Eurocode?
Quote from here:
Limit state EQU, dealing with static equilibrium, is defined as: Loss of static equilibrium of the structure... considered as a rigid body, where minor variations in the [actions or ...
CommunityBot
- 1
0
votes
2
answers
54
views
Steel beam splice design
What is a good source of design recomendations for beam splices? I'm designing a structure and I need some help with getting proper splice strength for certain beam size. To make it simpler, I need ...
- 8,222
0
votes
3
answers
50
views
Help understanding why bending moment is integral of shear
I am aware of the basics of Euler-Bernoulli beam theory but there is one thing that I have never understood satisfactorily. Where $M$ is the bending moment, and $V$ the shear force:
$$\frac{dM}{dx}=V\,...
- 1,330
2
votes
2
answers
231
views
How to design an enclosure around the load cell (Beam type)?
Hardware and Electronics Used: Arduino UNO, HX711 ADC Load cell amplifier, Load Cell (2Kg);
Currently, I am working on a project which requires me to put load cell along with the other circuitry in an ...
CommunityBot
- 1
0
votes
1
answer
23
views
Bolted plate static and dynamic friction explanation
I will not go into the exact details of the engineering problem. Still, I kindly ask for some help with a proper explanation because I am having trouble explaining the correct principle in this ...
- 35
0
votes
3
answers
317
views
Confusion about sign of beam's moment force
A positive bending moment bends a beam concave upward(or towards the positive y direction), whereas a negative bending moment bends a beam concave downward(or towards the negative y direction). (...
CommunityBot
- 1
0
votes
1
answer
47
views
Need to Align Line Directions Normals Along Specific Coord in APDL
In Preprocessor of APDL, I have built areas which are meshed with shell element and lines meshed with beam elements.
I have assigned Sections to Beam elements but when I view them their cross sections ...
CommunityBot
- 1
0
votes
2
answers
125
views
Is bending stress over round thin-walled tube cross section linear?
It is thin walled because roughly d=200mm and t=6mm of a carbon fiber wrapped tube.
The question is, if the bending stress $\sigma$ over the cross-section (in y-direction) is linear or not.
It is ...
CommunityBot
- 1
0
votes
0
answers
22
views
Normal Weight of RC Beam
Is 450kg/m for a reinforced concrete beam outlandish?
The dimensions are:
width: 0.3m
depth: 0.6m
I am designing a beam, and that is what I got.
- 1
0
votes
2
answers
1k
views
How can I understand shear flow in a beam cross section?
I am trying to understand shear flow and I am just not getting it. For example, one of the problems in Beer has an I-beam and there is both a horizontal and vertical force acting on it. So it has ...
CommunityBot
- 1
4
votes
3
answers
14k
views
Determining stiffness of a beam w/varying moment of inertia
I need to calculate $K$ or equivalent stiffness of a beam that has a varying $I$ across its length. $I$ has been given to me as a function of $x$, or length.
I have been unable to find a proper ...
1
vote
3
answers
80
views
What load would a 2" x 4' x 8' sheet of pink XPS foam wrapped in fiberglass using epoxy resin support if used as an 8' bridge?
I need to build a light weight ramp roughly 4' wide by 8' long. I've built similar out of 1/2" plywood and 2x4s. That's plenty strong but much too heavy. If I wrapped a 4' x 8' sheet of 2" ...
- 7,297
0
votes
1
answer
87
views
Need to find beam deflection of a steel tube
So I have a square tube of 40mm, 3mm wall thickness with a length of 1 meter. Both ends are fixed 25mm inwards. Load is 3kg centerpoint. Steel is SJ235.
I need to know the deflection of this beam.
...
- 1,231
0
votes
4
answers
73
views
Static Equilibrium of Rigid Bodies
When we talk about the idea of static equilibrium in engineering mechanics we consider the idealized case of a body which is a rigid body, meaning it cannot deform. Then we solve for the 3 equilibrium ...
CommunityBot
- 1
0
votes
2
answers
52
views
Do tensile and compressive stresses create moments?
Below are 3 examples I designed. My question is about the tensile and compressive stresses that occur in 3 examples under the influence of a horizontal force F=100N (earthquake force). I ask my ...
CommunityBot
- 1
0
votes
1
answer
506
views
MSC Nastran - BAR3/4 elements - can't assign any properties
I'm modeling a pipe in Patran, and I'd like to try bar3 and bar4 elements.
I assing the properties CBEAM to my geometry, but when I create the mesh, Patran tell me bar3 and bar4 don't support that ...
CommunityBot
- 1
0
votes
1
answer
372
views
What is the equivalent rotational/angular stiffness of a beam
I'm trying to model a larger system and working through a conceptual issue. I'm familiar with the concept of expressing the stiffness of a beam as an equivalent spring stiffness like in the image ...
CommunityBot
- 1
0
votes
0
answers
125
views
Calculating deflection of a cantilever beam using Young's modulus
I have looked at a lot of deflection questions on here and I didn't see anything that quite matched what I needed to know.
I am working through some curriculum for students and I am working through ...
- 1,330
3
votes
3
answers
5k
views
Is it possible to convert uniform loads to point loads?
I want to perform a structural analysis on a portal frame using a finite element solver to get a displacements and reactions for a load. The software library only accepts loads applied to node, not to ...
9
votes
5
answers
7k
views
Why is it unwise to choose cylindrical horizontal beam
I heard that it is unwise to choose cylindrical horizontal beam. My question is why?
- 472
0
votes
0
answers
24
views
FInding deflection on a uniform beam with supports ~ Incorrect answer
Hello I am asked to find deflection of beam in millimetres at different points.
The uniform beam is 3.55 meters long with a flexural rigidity of 32269Nm^2
It is under a uniform load of 92N/m and is ...
