# Questions tagged [bending]

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### 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\,...
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Hi Please help me answer my homework about simplifying load diagrams quickly, Thanks. I don't know how to simplify the left-hand side but on the Right-hand side I'm guessing I have to move that 5 ft/...
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### Mat Footing (Bending Moment Issue of the Short Strip)

Hi I'm a civil engineering student, I wanted to ask for help and clarification for the design of mat footing. I used the Rigid method and based my design on the ACI 336_2R and Foundation Engineering ...
59 views

### Analysing Bending in a Linkage Member

Context: I'm designing a linkage mechanism as part of a university robotics design project. From previous analysis, I have determined the forces and torques applied to each member at all points in ...
50 views

### Which beam deflects and twists more, open section or closed section?

Two beams, one open section (like an I-beam with flanges and web) and the other closed section (like a hollow square section) are cantilevered and have the same overall cross sectional moment of ...
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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 ...
41 views

### How to CAD: smooth width transition in sheet-metal bends

I am working with FreeCAD 0.20 and Sheet Metal work bench 0.2.63, but universal CAD tips are also welcomed. As shown in the image, I would like to bend sheet metal with smoothly chancing width along ...
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### Are there structural (or code) reasons for choosing longer or shorter beam spans (besides bending moments, and ignoring cosmetics)?

When selecting the length of beams for a bridge, the better approach is to choose multiple full-length beams. Unless there is a compelling reason, one would not choose multiple shorter spans. An ...
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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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622 views

### Calculating Pressure Loss (K Value) of Pipe Bends at varying Angles

I am analyzing the total pressure loss of a run of pipe that has several pipe bends at varying angles (30, 60, 45, 90, etc. degrees). Reading through CRANE: Flow of Fluids Through Valves, Fittings, ...
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### Spring making machines

There's lots of videos of high-speed spring making machines floating around e.g. YouTube, typically taking wire stock of up to a millimeter or so in diameter and producing items which are clearly ...
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### Second moment of area (moment of inertia) for annulus segment

I am a Mechanical Engineering student and I'm working on some calculations for an assignment at a company. As a part of this assignment I need to calculate the moment of inertia (Ixx) of a segment of ...
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451 views

### Correct beam theory for calculating radial force in bearing due to a bending moment in beam?

I am designing a cylindrical shaft that has a round disc at its top. I am hoping to seat this shaft in 2 radial bearings and couple to a motor. The image below gives an overview of the loading diagram....
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### Truss beam like structure strength per height

The second beam is 2x the height of the first one. Is 1 stronger then 2 to bending force (arrow shows direction, supported on the sides)? If it does, I'm trying to figure out why, because they both ...
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### Bending moment capacity of T-cross-section (reinforced concrete)

I have a question regarding a simplification/derivation of the (ULS) bending moment capacity of a given T-cross-section, with compression-zone on the flanged side. The problem is that the rebar-strain ...
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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 ...
350 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 ...
28 views

### Is the a similar method of calculating moment in inelastic bending like in the case of torque for inelastic torsion?

When calculating for Torque in torsion or for Moment in the case of bending, the concept is usually first introduced with the simplification of the assumption that the stresses and strains are in the ...
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### Bending stress and permissible bending stress

I have a task to choose a material and gear module for a double step up gearbox with equal ratios The first pinion has a max bending stress of 296 MPa and the gear has 239 MPa. The permissible being ...
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### Calculating how many bolts are needed to hold parts

Suppose we have a stack of thin metal sheets, layered on top of each other. Let's say 20 sheets, 0.2mm thick, and each sheet is 70mm by 70mm. Let's also say that the sheets are not totally flat, so ...
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### What process is involved in freeform 3D tube bending?

I have seen 3D freeform tube bending in videos such as this, this, and this. I would like to ask what process is involved in such machines. I can see a swivel mechanism used for bending. What is it ...
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1 vote
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### Does Bending Stress Affect Natural Frequency?

I have been researching about the factors that affect natural frequencies, particularly about the effects of stresses. Most of what I have found only discusses compressive and tensile stresses though, ...
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1 vote
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### Bending analysis of beams with varying cross section

All problems I solved in MoM class regarding beam bending involved a beam with continuous cross section. But is the process the same for a beam with varying cross section? For 'same process' I mean ...
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### How to reduce a welded iron pipe without bending it?

I would like to reduce the diameter of an iron (welded) pipe without bending to the side, where the weld is. With the usual procedure, the result is as follows: I am using the usual pipe reducing ...
94 views

### Composite Beam Theory - Calculating torsion and beam deflection of a composite beam made up of a pipe inside a pipe

I am trying to calculate two things. First the beam deflection of my model after bending and second angle of twist after applying torque. My model is composed of two tubes (cylindrical hollow beams). ...
1 vote
123 views

### How to find the location on the 2-support beam where the deflection will be biggest?

Consider the uniform indeterminate beam as shown above. This beam is to be subjected to a single, 80N point load (acting down ) somewhere along its length. What is the procedure (i.e steps and logic) ...
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### What is the theory behing why is it harder to bend a block of wood on its thinner side when load is put onto it

What is the theory behing why is it harder to bend a block of wood on its thinner side when load is put onto it as opposed to when the wood is on its thicker side. For example, if you had a 1x2x20cm ...
315 views

### Relation between welding bead and outer diameter of a pipe?

How can we find a relation between welding bead and outer diameter of a pipe? Welding bead is inside of the pipe and I am using M.S. pipe. Dimensions are listed below: Pipe OD=25.4mm Thickness=2mm ...
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### Justification of static equilibrium for a cut structure/frame

Axial deformations are ignored. This structure is under the specified force: Is the internal shear force in column BC equal to that of column DE? If we cut the structure at middle of BC and DE ...
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### 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 ...
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### Max bending moment estimate

Context: I study aerodynamics and want to design and build an RC wing to put the theory I learned into practice. The essence of the theory I learned is: Given some mass of wing building material, how ...
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### Are you able to compute the bending moment exerted on the inner edges of parallelepiped box under inner pressure?

Suppose you have a parallelepiped box of dimensions $a\times b\times L$ with $L\gg (a+b)$, filled with simple distilled water exerting a uniform and constant inner pressure $p$ as reported in figure. ...
1 vote
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### should the hachures in moment and shear diagram be vertical?

when we plot the shear or moment diagram we add hachures to the area created with these diagrams , in most cases we see vertical hachures, is it represent the internal forces? or its just used to ...
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### Max length of 12mm OD steel rod for CNC axis [closed]

Standard rod used for CNC guides, outer diameter: 12mm. Material: Ck55 steel, hardened to 60 HRC (according to store) What would be the maximum length I can have before the rod starts to bend? The ...
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### How to calculate the deflection displacement of a circular looped, closed bending beam?

There is a given ring A, with a given cross section B. Ring A is placed on Columns C. The number of the columns is a variable, but minimum three. The linear distance X between two columns can be ...
1 vote
627 views

### Maximum shear in a beam

Engineering books and lectures typically make two things clear: Maximum bending stresses (normal) develop at the beam surfaces, that is, at the greatest distance from the neutral axis. Shear stresses ...
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### 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 ...
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### Why can't I-beam resist torsion but can resist shear stress due to transverse loading?

It is already known that the I-beam is very bending resistant (causes less deflection for the same transverse load and also results in lesser stresses relatively). But for an eccentric transverse load ...
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1 vote
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### Which force generates the reaction moment in a fixed support

The question is: Which force causes the reaction moment at a fixed joint ? Lets consider a very simple example, a beam with one end connected by a fixed support to a wall. I understand that at A, ...
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### Is bending moment along a beam independent of the cross sectional area of the beam?

We know this that if the a cantilever beam (of any cross section) is fixed at one end and a transverse force is applied on the other, then it will bend. However, we just casually assume that the ...
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### Metal sheet forming - material properties when switching material

What does one have to look out in material properties when changing material grade in cold sheet forming operation (example: from DC04 to DC03 or to DC01). Operation is mostly made of 90°bends and ...
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### Does the Superposition principle actually make sense in reality for a rod subjected to bending and axial force togehter?

Consider a rectangular rod, for example. I fix it from one end and apply a transverse force on the other (to cause bending) and also a axial force (lets just assume its compressive). Now, according to ...
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### Shear and Bending Moment

A square tube is slid into a larger square tube. If a load is applied to the end of the inner tube, I would think that inner tube would mainly contact the outer tube in two locations as the load is ...
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### Find the maximum stress at a point in a machine member

A machine member having a diameter of 50 mm and a length of 250 mm is supported at one end as a cantilever subjected to different forces as shown in the figure. Find the maximum stress at points A and ...
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### Why do we always need to calculate the 'Moment of Inertia' about neutral axis for bending?

I was having a look at the bending stress derivation in few of the books. The derivation indicates how each of the element in the bending stress equation is derived into that equation. However, for ...
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1 vote
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### Unusual bending moment at simply supported beam in etabs [closed]

The horizontal beam is simply supported. I have assigned pinned to released the moment at the both ends. However, there's moment spike near the end in ETABS, what's the problem ? I have checked thru ...
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### What are the units used in beam bending equations? Do they matter?

I was just wondering whether or not the standard beam bending equations worked for all units. E.g. imperial and metric etc. From what I'm guessing it shouldn't really, since once we plug everything in ...
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### How do I EXACTLY calculate the k-factor for metal bending?

Introduction I've recently started to work with metals and the process of bending them. There is a lot more math involved than I initially thought. All the break press operators just have a ...
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### BMD of the beam joined at intersection

4 beams are supported by the column at one side, another side is jointed together at the intersection. I have assigned UDL of 20 kN/m on all the beams. 2 beams are longer (3m), 2 beams are shorter (2m)...
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