Questions tagged [deflection]

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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 ...
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2 answers
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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 ...
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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 ...
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1 answer
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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 [2] showing the results of applying hydrostatic loads to an acrylic ...
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2 answers
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Maximum Deflection for simply supported beam under arbitrary triangular loading

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 ...
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My solution of this deflection of beam problem not matching with the book solution

Here is the problem and it's solution done in book - https://imgur.com/a/DRS7OvN Here is my solution - https://imgur.com/a/Yd9JGuC The book solution has 1/384wL^4 term but I am getting 1/128wL^4. ...
1 vote
1 answer
54 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 ...
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1 answer
726 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 ...
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2 answers
114 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 ...
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3 answers
620 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 ...
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211 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 ...
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3 answers
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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 ...
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1 vote
3 answers
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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 ...
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2 answers
299 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 ...
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1 answer
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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 ...
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3 answers
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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 ...
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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/...
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1 answer
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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 ...
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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 ...
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1 answer
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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 ...
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4 answers
300 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 ...
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1 vote
2 answers
983 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 ...
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377 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(...
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2 answers
323 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 ...
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1 answer
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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. ...
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1 answer
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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 ...
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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 ...
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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 - ...
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1 answer
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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 ...
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2 votes
2 answers
462 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 ...
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1 answer
207 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 ...
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2 answers
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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 ...
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3 votes
1 answer
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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? [...
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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. ...
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1 answer
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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, ...
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2 answers
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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
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2 answers
310 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 ...
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263 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 ...
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1 vote
2 answers
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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 ...
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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 ...
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1 answer
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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 ...
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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 \...
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1 answer
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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 ...
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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 ...
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0 answers
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Most efficient way for finding the rotation angles after moment distribution (Cross method)?

First of all, I have taken a look at the Grinter's method, which is similar to Cross, but balancing angles instead of moments. My question assumes that we are using the Cross method, and not the ...
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1 answer
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How can I calculate the maximum load of a steel box section frame?

Is it possible to calculate the maximum load of the steel structure shown in the image using its dimensions?
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3 answers
3k views

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 ...
2 votes
1 answer
1k views

Bending equation and max deflection of UDL and multiple point loads

I have a beam, simply supported with 2 points loads and 2 UDLs. The loads are symmetric about the centre of the beam. I've tried to derive an expression for the moment along the beam and then via 2 ...
2 votes
2 answers
243 views

Deflection of a stack of disks under applied force/pressure

I'm trying to calculate the deflection of a stack of metallic disks, when subjected to a force. In the case of the figure below, representing a valve for a shock absorber, the force is due to a ...
1 vote
1 answer
147 views

Which diameter and thickness pipe to choose

I'm building a roller for a "pool" cover I got at home. The cover weighs 10kg (8kg but I'm considering some weigh added by the water present on it). I have a bosch profile structure where I will ...
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