# Questions tagged [deflection]

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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 ...
31 views

### Maximum deflection of PSL + steel beam

I'm an amateur structural engineer, and I'm not understanding how to calculate multi-material beam deflection in my particular scenario. I start with a simply supported PSL (wood) beam that is ...
31 views

### Which Deflection Formula is Correct for Hollow Aluminum Tube, Simply Supported, Uniformly Distributed Load?

Which deflection formula is correct for simply supported hollow aluminum tube with a uniformly distributed load (I've read conflicting answers online): δ = (5 x w x L^3) / (384 x E x I) δ = (5 x w x ...
22 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 ...
102 views

### Find deflection and reaction force of a beam using Castigliano's energy method

I want to find the reaction force of support A and also find an equation for deflection using Castigliano's energy method for this beam. I know that the reaction force of A is 65.625 N but my solution ...
25 views

### 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 ...
334 views

### Calculating deflections on an inclined beam

I'm applying a force to a stepped inclined beam (that's what I'm calling it; don't know what the correct technical term would be) in which it's essentially a cantilever with the first section angled ...
69 views

### Cantilever Beam Deflection under Plane strain

I have a university code that calculates the maximum deflection of cantilever beam of length, $L$ subjected to a point load, $P$ on its free end. The software assumes plane strain conditions. I ...
25 views

### Do axial displacement experiments under hydrostatic load scale linearly to any size?

In J. D. Stachiw's book Acrylic plastic viewports for ocean engineering applications [PDF] on page 337 it includes a Figure 7.12  showing the results of applying hydrostatic loads to an acrylic ...
158 views

I am trying to get the: maximum deflection location of maximum deflection deflection at any point For a beam under an arbitrary triangular load (i.e. a, b, c, and w can vary). I tried to solve this ...
1 vote
56 views

### Principle of virtual work "geometric proof"

I spent a full day searching for and trying to understand why in this "proof" of virtual work makes sense. I've come to understand the idea from D'Alambert's principle, but I want to ...
2k views

### deflection of mild steel hollow tube beam

I am trying to compute the deflection of a hollow tube of mild steel, and my computation seems to give radically different results than a couple of online calculators. Apparently one is in error. The ...
188 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 ...
1k 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 ...
383 views

### Deflection of Cantilever Beam with Midpoint Spring, Integration and Superposition Methods

How can I get the deflection required below using 1) the Integration and 2) Superposition methods (two ways)? The beam $AB$ is supported by a spring $CD$, which is fixed at $C$ with constant $k$, and ...
5k views

### How is load bearing capacity of a leg of steel angle calculated?

Suppose a section of steel angle is used to support a structural beam, which would otherwise have no available bearing, as in the following sketch. Assuming that appropriate connection/fixing on the ...
1 vote
365 views

### Castigliano's theorem for deflection

Consider a prismatic bar fixed at one end and acted upon by a force P at the other. According to Castigliano's theorem we can determine the deflection of point A by partially differentiating the total ...
710 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 ...
71 views

### Ways to stiffen a HSS profile?

I have an issue with a post that’s deflecting a little bit too much. Picture a 10 foot HSS c-channel section, used vertically as a post. Web/flange 4.5 x 1.75 @ 3/16 thick. Clients (friends) insisted ...
1 vote
304 views

### Utilizing symmetry in statics problem

I am given the structure below, and supposed to find the forces occuring in $A, F, E, D, C$ and $B$. The task hints of using symmetry, as several forces are equal in magnitude. Supposedly, $A=B$, and ...
4k views

### How much deflection can/should I accept with Aluminum Extrusions?

I plan building things with aluminum extrusions. On this website I can calculate the deflection depending on the profile length and load. https://8020.net/deflection-calculator I.e. if I select a 20/...
58 views

### How to determine beam deflection with this unusual configuration (diagram attached)

So I've got a support system shown here in the attached image. Comparing configuration "A" to "B" it seems intuitive that "A" could support a larger load. The stubs are ...
1 vote
128 views

### How does the stiffness of semicircular beams connected in series increases?

I am working to reduce the deflection in a cantilever/ dive board at work.$300 mm(L) \times 30mm(B) \times 2 mm(H)$, i.e. it's a rectangular cross section currently. I can't change the material, or ...
79 views

### Calculating the load on the end of a beam

We ordered a really nice light for our dinner table and ordered a special "lightswing" seperatly. The light that we ordered however is heavier than the 'lightswing' is rated for. Please see ...
423 views

### Deflection of a fixed-fixed pvc pipe under self weight

I would like to start by saying I am not an engineer, so I apologize if this question seems simpleminded. I am making a manual tarp reel from pvc pipe, and I am trying to decided whether to use ...
1 vote
1k 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 ...
505 views

### Large deflection of a non prismatic cantilever beam under distributed load

Here's what I got trying to calculate the large deflection of a cantilever beam with two different cross sections under a uniformly distributed load: From the figure, the shear force is:  V(s) = q(...
534 views

### How can I find deflection in a member that doesn't have a constant area moment of inertia?

I'm trying to calculate the maximum deflection in a simply supported member with a uniformly distributed load. The trouble is this member does not have a constant area moment of inertia. I've drawn a ...
130 views

### simply supported beam with a midspan load

First off non-engineer apologies, A plate of 5251 Aluminium is used to support the load of a centrally seated human I estimate a load of 1 kilonewton. The beam measures a length of 1000mm, 100mm wide. ...
186 views

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

This is related to this question It is the case of a simple cantilever beam having a uniform rectangular cross-section. cantilever beam composed of separate planks - taken from The question in the ...
1k views

### Deflection of a rectangular plate simply supported (transverse load)

I am looking for the formula allowing to calculate the deflection of a rectangular plate with a "transverse loading in its center" (maybe the kind of loading will be more clear with this picture : I ...
1k views

### Sign convention for deflection and slope of beam?

What is the sign convention for deflection and slope of a beam as shown in the diagram below? When I derive the formula using Euler-Bernoulli for deflection and slope myself, I end up with - ...
386 views

### Calculate deflection of a beam with an arbitrary shape

I have a beam with rectangular cross section, but rather an strange shape in the length wise direction as seen below: So I have taken out the symmetry part of it: And it actually has some nice ...
608 views

### How to determine the deflection of a wire mesh under wind load?

I am trying to extend a metal wire mesh over a large distance, while tensioning it to limit the deflection of the mesh due to the wind as much as possible. After doing some research I came across ...
331 views

### Flexure Deflection - Both ends fixed (one translation free)

I have a flexure problem. One of its ends is fixed to a frame (say F1) which is stationary (no rotation & no translation) and the other end is also fixed to another frame (say F2) which can move ...
141 views

### Deflection In Multistory Structure

When analysing and designing a structure for the serviceability limit state the deflections of each beam must be found. When considering a multistory rigid jointed structure (as below) and applying ...
4k views

### What plastic material is best for a snap-fit design?

I'm designing a plastic holder that will secure a metal part with snaps. Which plastic will be able to take multiple removals and re-insertions without getting weaker (bent out of shape) over time? [...
1 vote
121 views

### How to calculate load on roller to create given deflection?

I am trying to calculate what loading on a fixed roller will create a predetermined maximum deflection. I ran some calculations, but the values I'm getting are significantly lower than I would expect. ...
103 views

### How to size a rectangular steel tube to hold certain weight?

I would like to build a shelf (1m width and 0.5m depth) using only four rectangular steel tubes on for legs. Each legs are at the end of the rectangular tube. I would like to put 500kg on the tubes, ...
116 views

### How to calculate the deflection of beam that is reinforced through formula?

Example an aluminium tube reinforced with steel tube inside. 100*50*2mm thick aluminium with 80*40*3mm MS tube
347 views

### Pin joint system displacement question

A pinned system comprising bars of the same material and cross-sectional area is subjected to a vertical load P. I am required to form a relationship between FAB and P. The first part of the ...
313 views

### Why does rebar in reinforced pre-stressed conrete reduce in deflection if compressive stress is applied to member?

According to What is Prestressed Concrete? - Practical Engineering, one way to reduce deflection in the steel rebar is to pre-stress the rebar by applying compressive stress in the member before ...
1 vote
87 views

### Where is the axis of bending for a box lifted by a crane?

A box is being lifted by a crane. Sometimes the box will be completely full, and sometimes it will only be partially full (indicated by the gray shaded regions). The question is, where is the axis of ...
366 views

### simple supported Beam deflection question involving two point loads and a UDL

so i was given a problem by my mechanical principles teacher to work out the max vertical deflection of a simply supported beam with two point loads one a distance of 5.3 away from A and another 5.9 ...
1 vote
241 views

### FEA: What is the difference between a spider of RBE2s and multiple SPCs

I am not sure what the difference is between using a spider of RBE2s. and multiple SPCs across a face. I've heard that the spider is the more accurate method as multiple SPCs make the model overly ...
3k views

### Deflection of Rectangular Plate with 2 Simply Supported Edges

As shown in the figure provided, a Uniform load acts upon a rectangular plate with edges at Y = 0 and Y = b which are simply supported. Using this form of the Plate Equation: \$\frac{\partial^4 \...
228 views

### Why do we increase the minimum beam/slab depth if we increase the grade of the reinforcement to control the deflection

I've just started to study reinforced concrete design and I came across this in the "Design of Concrete Structures" by Dr.Nilson. and I was wondering why do we increase the minimum thickness if we ...
1 vote
242 views

### 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