# Questions tagged [beam]

Questions about the theory and applications of structural elements designed to resist bending.

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### Deflection of a cantilever beam composed of separate (not bonded) planks

In the case of a simple cantilever beam having a uniform shape and being loaded at its end - the calculation of the deflection at any point along the beam is well known. What happens if we split it ...
36k views

### How to deal with a point force acting right on the hinge of a beam?

I have been attempting to solve a question where there is a point force acting on the hinge of a beam. Here is the problem: I am not sure how to deal with the 2 kN point force at $C$ ($C$ and $E$ are ...
• 149
6k views

### Why does a continuous beam have less deflection than a pair of simply supported beams?

Inspired by this question, and also this answer to a separate question. I have two beam models, one with two independent spans (a full hinge), another is a continuous beam over both spans (only ...
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3k views

### Deriving the deflection force equation for a beam that is fixed on both ends

I want to calculate the force-displacement equation for a beam that is fixed at both ends. I think I should use the superposition principle but I am not very sure how to get started. I know that for,...
• 41
62 views

### Continues beam deflection

does any one know how to derive the deflection equation of a continues beam of three span of equal length and equal UDL load Here's a link these two pictures shows my tries to solve the question
10k views

### How do I calculate the forces on a desk and its legs?

I have a design for a desk, and I'd like to not just guess at how strong it'll be, but I can't find an explanation on how to figure out all the forces involved that doesn't assume I already know a lot ...
• 121
2k views

### Large deflection of a cantilever beam with distributed normal load

I have a strip of stainless steel encastree'd at one end to which is applied a constant pressure on one side, and I need to know what the deflection equation y = f(x) is at equilibrium. If the ...
12k views

### Multiple Varying cross section beam deflection

How do we calculate the deflection of a cantilever with two or three cross-sections, and different forces acting at the end of each section?
26k views

### How much weight can an aluminum tube beam support?

I'm building a set of monkey bars for my kids and want to use aluminum tubing (6061 T6) for the rungs. The tubes will be 3 feet long and 1 inch outside diameter. Supported on both ends with a circular ...
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2k views

### Buckling vs. Yielding Failure of Columns

As I have been working through examples of construction projects, I've noticed that in nearly every case of a structural column (sample size considers only homogeneous material columns, no composite ...
100 views

### How to find a beam for my (simple) application

I have a spanof 9m that I bridge with a (as yet unspecified) beam. From this beam hangs a load (a pipeline), right in the middle, of 4.295 kN. The beam is simply supported. I want to use an IPE steel ...
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1 vote
83 views

### Proving the advantage of a composite beam

The textbook that I'm following for studying bending stresses in beams, states that - "Engineers purposely design beams in this manner (composite manner) in order to develop a more efficient ...
1 vote
2k views

### How to calculate deflection of a cantilever beam subject to point loading

I am trying to solve the following beam deflection problem: The cantilever beam is subjected to the point load at C. Generate the equation for the elastic curve by using the double ...
• 291
1 vote
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 ...
1 vote
4k views

### Beam deformation under trapezoidal load

Can somebody help me find the equation for the deformation of a simply supported beam under trapezoidal load (with intensity Q1 and Q2, at starting point X1 and end point X2)? I am trying to find it ...
1 vote
7k views

### Ceiling mounted punching bag without compromising structure or floor above

This question is regarding the safest way of installing a heavy punching bag of 100 lbs from the basement ceiling. Above the basement ceiling is a wood floor. The goal is to sleep soundly at night ...
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936 views

### Any way to approximate effect of two point loads with just one?

Imagine a 3D problem where the goal is to calculate the max. cantilever beam deflection. There are 4 equal point loads A, B,C,D separated equally from the beam's major axis. Is there a way to ...
• 13
528 views

### Direction of shear in beam cross section - how to understand the convention

In an I-beam, the shear flow is usually shown drawn as on the left, not as drawn on the right. I do not understand why. I do understand: The total horizontal shear force must be zero, consistent with ...
• 21
875 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 ...
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324 views

### Determining the ratio of bending moments in parts of a composite beam

Consider a composite beam formed by sandwiching a wood beam between two steel plates, whose cross section is shown. Say the beam is loaded by some arbitrary loading, due to which at any cross section ...
47 views

### Setting direction vectors for Lines in ANSYS APDL

I am using beam elements to mesh lines with "pre-meshed" shell areas. Problem is that the ANSYS sets Line Direction vectors on its own. This results in Cross sections assignment flipped from ...
5k views

### Simple beam with cantilever ends

I'm trying to find the maximum bending moment and deflection for this symmetrical simple beam. The formulae I can find, deal with either cantilever beams with one fixed end, or continuous beams ...
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