# Questions tagged [beam]

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

93 questions with no upvoted or accepted answers
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### 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 ...
356 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-...
239 views

### Design a beam that is straightened with force on one end

From here, I read that if you have a straight beam, bend it with force at one end, and then create a beam with the resulting curvature, the equal and opposite force won't make a straight beam. What ...
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### Shape of a beam that is bowed under compression?

Suppose you have a uniform beam, such as a piece of plywood that is 4 feet long, six inches wide, and half an inch thick. Suppose you cause it to bend by attaching, for example, a string under ...
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### Moment Of Inertia Specifications AISC

Is there some regulatory body/inspection that verifies the AISC specified Moment(s) of Inertia for steel I-Beams? So for example, if a mill produces a W8x21 and says hey, it meets the specs, it's 8 ...
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### Problems with shear force diagram in beam model

I am starting to learn how to use ANSYS APDL. So I don't have much knowledge in the software. I have modelled a cantilever beam (with beam188 elements) and the only load that i have applied was the ...
1 vote
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### How do I calculate kg/m for 5 boards sitting on 3 beams

I'm new to this, thank you for your patience, I have some wooden boards that each weigh 5.5 kg with dimensions of 120 cm * 60 cm I also have some wooden beams with dimensions of 3 meters length and 10 ...
1 vote
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### 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-...
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### On rectangular section beam properties of plate stiffeners

I am trying to understand the expression of the vertical dynamic stiffness $K_T$ and the rotational dynamic stiffness $K_r$ which appears in this paper where they consider a semi-infinite plate ...
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### 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 ...
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### 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 (...
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### 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 ...
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### 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 ...
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### Pin connection on beam - FEA analysis

I am establishing a MatLab FEA code for determining the stiffness of a structure. Diagram of the structure is added below. I have established a code for determining the stiffness of the structure, but ...
1 vote
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### Rotational bending in Timoshenko beam theory

The Wikipedia article on Timoshenko beam theory says: The model takes into account shear deformation and rotational bending effects, I am familiar with shear deformation, but what is meant by "...
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1 vote
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### Simple beam deflection of cantilever beam

Recently I had need to prove the beam deflection equation for a simple cantilever beam with a point load at the end. The equation would be in reference to the Euler-Bernoulli theory taught in most ...
1 vote
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### Derivation of Bimetallic Strip Stress in Roark's Formulas

I am trying to understand some analytic expressions given in the handbook Roark's Formulas for Stress and Strain for bimetallic strip stresses. Namely, Roark's Formulas give the formulas \text{...
1 vote
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### How to add Beam cross section properties to imported mesh in Ansys?

Ansys Workbench 17.1 I have a mesh that was imported from Abaqus into Ansys but the beam cross section data is missing. As a result the structural model omits the beam elements. How do I access the ...
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### Equivalent spring of beam supported by springs

My professor gave us yesterday a problem to calculate the equivalent spring of the system shown in the attached figure. The problem: a cantilever beam supported by two springs $k_1$ and $k_2$ located ...
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1 vote
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### How can I use the bending stiffness of corrugated cardboard to determine maximum stacking heights of pallets loaded with glass bottles?

I am doing a project at the moment which involves improving the packaging operation at work. Right now I am looking at ways to improve packaging selection based on engineering principles, rather than ...
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### 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. ...
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### Distribution of shear stress in beam bending

Beer, Johnston, and DeWolf's Mechanics of Materials includes the following image of the distribution of shear stresses in a bending beam: (Axes and load vector carried forward from Fig 6.1 in the text ...
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### Why don't we calculate buckling in composite beams?

I have a frame, it consists of steel beams and my flooring is a composite deck. It consists of composite beams that are hinged to my steel frame beams. Composite beams do not transfer moments. Now, ...
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### 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 ...
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### 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 ...
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### Finding deflection on a uniform beam with fixed supports ~ Incorrect answer :(

This question has asked us to find the deflection of a beam (in millimeters) if the beam is under a load of: f(x) = 9.46(x+0.82)(9.2288-x) N/M The beam is supported with fixed supports at both ends ...
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### How can I mount this plate on a Steel Beam?

As mentioned in the question, I am looking for a method to attach this mounting bracket to the flange of a steel beam that permits effortless removal and remounting without permanent fixation.
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### How to suppress longitudinal stress waves in a beam in FEA

When simulating a bending beam in FEA mimicking the textbook model and approach, unwanted stress waves appear. How to suppress longitudinal stress waves in a beam in FEA? To add friction/damping?
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### Is there explicit expersion for the natural frequency of a cantilever timoshenko beam?

I am trying to find a closed form solution for the natural frequency of cantilever Timoshenko beam. In mechanical vibration (Rao, 5th edition) he outlined the details to include the Effects of Rotary ...
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### Multiple varying cross section beam with distributed load - FBD Method?

Based on the 2 different threads read below : Multiple Varying cross section beam deflection + Multiple varying cross section beam with uniform loads I'm trying to set up a calculation sheet (Excel is ...
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### How much weight can aluminum square tube support?

I'm building a bed platform in a campervan and trying to determine what type of aluminum tube to buy. I'm thinking to purchase 6061-T6511 aluminum Square Tube with 1.5" width, 1.5" height ...
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If we take the moment about A from the $F_{BC}$ will make the body want to rotate counter clock wise but If we take it from the point C it will make the body rotate clock wise whats the mistake?
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### Uniform Direction for Line Directions

Despite several similar questions and my efforts, there is still no solution so far. Presently, ANSYS gives Directions to Lines on its own which are flipped even for two collinear lines. As a results ...
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### 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 ...
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### Mass Brick Settling Causing Excess Load On Center Beam

I live in a 115+ YO building and recently had my kitchen remodelled. During this the subfloor was replaced (old 1x6s in bad shape). I noticed a significant bow in the joists with the central steel ...
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### 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 ...
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### 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. ...
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### 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 ...
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### Can someone help me with solving this beam problem using Rayleigh Ritz Method, my trial function is not working

The question is there is a two element beam joined together. The first element is 5m long and the other is 4m long. At the outer nodes there are roller supports and at the middle point where two ...
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### 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?
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### Justification for choice of beam stiffness at pinned far-end member

I’m reading off an example provided by the ICE structural analysis book, specifically example 4.7 (moment distribution method) I dont seem to understand why the stiffness from member D-C is 4EI/L ...
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### 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 ...
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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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### 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 ...
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### The Effect of Accelerometer Position on Modal Analysis of a Cantilever

We have obtained the first two vibration modal frequencies of a composite cantilever (33 gm). We placed the accelerometer (3.4 gm) near the fixed end and the two frequencies were F1=30 Hz and F2 = 256 ...