Questions tagged [beam]

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

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What is the bending moment formula for continuously supported beam of equal span?

Is there a standard chart in Eurocode for the maximum and minimum bending moment in uniformly loaded beam for indeterminate structures where we can use directly? Many textbooks give different ...
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1answer
114 views

Wing as cantilever beam (beam-rod) model for aeroelasticity fluttering analysis

I recently bumbped into a rather basic but interesting question on aeroelasticity. I've learned to derive the fluttering critical speed from Pines's theory but it involves some spring stiffness like ...
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1answer
59 views

How to find maximum acceptable deflection?

I have a beam. I have its Young's modulus. I don't have its maximum acceptable deflection. How can I determine the maximum acceptable deflection without breaking the beam?
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136 views

Longitudinal impact of steel rod on a steel plate to verify the contact duration

So I'm doing an experiment to verify the contact duration when a steel rod (Material: Mild Steel) is allowed to free fall longitudinally on a steel plate. The arrangement is real simple: The rod is ...
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1answer
94 views

Translating the name of a type of beam from Russian to English

I am trying to translate the name of a special kind of beam from a set of Russian-language drawings. The dictionary translates the name as simply supported beam, but it's not that simple. There is a ...
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1answer
3k views

How to find the reaction forces, moments and the displacement of the fixed beam with a link?

The beam is fixed on both ends and there is a link in the middle. There is a force F on the link. My approach to solve this problem: A free body diagram is cut at the link and made into 2 systems. ...
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1answer
448 views

Reaction forces in a structure

I have the following structure, in which I am failing to calculate the two reactions: Cz (apparently vertical) and Dz, in the roller support of the beam. The beam length is 7.5 m, the reactions Az, Cx,...
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1answer
2k views

What is the formula for deflection of an end-loaded cantilever rod beam?

For a cantilever beam of circular cross section, loaded at the end, how does the deflection of the free end vary as a function of beam length and diameter? I expect the answer will be something like: ...
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Determine shear flow direction in profile/beam section

I have been looking at the location of shear flow centers for profiles for my mechanics of materials course. I am trying to figure out how to determine the direction of the shear flow in a given beam ...
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186 views

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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71 views

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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1answer
787 views

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 ...
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694 views

Steel Continuous Beam Structural Diagram

Here's an image of my structural plan that my group and I are designing for a university assignment. It is a 7-story steel structure with bracing at the two ends and at the verticle core near the ...
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1answer
252 views

What is the logic to solve this cantilever problem?

I solved it using the logic that the vertical link of the beam is basically there to make the beam act like a cantilever. So I think it is a cantilever problem. Therefore, $$EI\frac{d^2y}{dx^2}=-px=M$...
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1answer
98 views

Number of layers in a laminated steel transplant, using Young's Modulus

I'm not sure if my calculations are correct for the above question. $$ E = \frac{\sigma}{\epsilon} = \frac{\frac{My}{I}}{\frac{\delta}{L}} = k. \frac{1}{I} $$ Where k is constant for both beams, ...
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104 views

How can the linear relationship between curvature and bending moments be verified?

As part of an experiment, I'm verifying the existence of a linear relationship between curvature and bending moments for three beams using different materials. The plotted data can be seen below. ...
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1answer
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How can we know “by inspection” the location of maximum deflection of a simply supported beam with a point load?

I am working the following problem: The simply supported beam shown in Fig. 12-12a is subjected to the concentrated force P. Determine the maximum deflection of the beam. EI is constant. ...
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1answer
1k 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 ...
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2answers
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Given the tensile strength of a rod, how do you calculate the max weight that can be hung from it?

Given a 3.25" long, 0.125" diameter rubber rod with tensile strength 1200 psi supported on both ends, how much weight can you hung from the middle of it without breaking it? (This is not homework I am ...
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76 views

Is a force to the right positive?

I am trying to do this question and I have everything but one. Solving for $A_x$, $x$ force at $A$. $$\begin{gather} F_x = 6\cdot20 + A_x \\ A_x= -120\text{ kN} \end{gather}$$ Is this correct? ...
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2answers
443 views

Are linear beam element solutions ever exact and when are they used in practice?

In qualifying the results of a Finite Element (FE) beam model, I'm realizing that I dont understand FE beam elements as well as I should. Is there a procedure to determine what order beam element is ...
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2answers
10k views

Determining stiffness of a beam w/varying moment of inertia

I need to calculate $K$ or equivalent stiffness of a beam that has a varying $I$ across its length. $I$ has been given to me as a function of $x$, or length. I have been unable to find a proper ...
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2answers
643 views

Maximum deflection of a beam, fixed in one end and concetrated load at free end [closed]

A 2 m long beam fixed in one side with a 2000 kg concentrated load at free end. Profile of the beam is HEB100 material S235. I would like to know if the beam will break under this load. If ...
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137 views

Undesired vibration of a beam under foot traffic

The other day I was in the waiting room of a doctor's office in a new building as part of UCLA medical complex. A new construction as part of multi million dollar extension of existing medical complex ...
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1answer
2k views

The boundary condition(s) for a continuous beam

I have a continuous beam across a center column (not sure whether I've draw it correctly or not) The Displacement and force diagram is as shown: The first diagram is the bending moment, second the ...
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1answer
11k 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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1answer
351 views

Why do we need to take distance of center gravity of a distributed load to a point in order to calculate moment?

From the picture above, in order to calculate the moment of load acting on the beam we take moment $M=\frac{W}{L}×L×\frac{L}{2}$. Why can't we calculate the moment as $M=\frac{W}{L}×L×L$? Why do we ...
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1answer
114 views

IPE Beam weight

In civil engineering calculation I have seen weight of IPE 300 profile expressed in kN/m2 unit. IPE 300 0.42 kN/m2 I know IPE 300 is approximately 42.4 kg/m. How did they calculated that value ...
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2answers
454 views

Deflection of beam, according to thickness of top plate and bottom plate

When there is one rectangular beam like below image, I would like to know how the beam is deflected according to thicknesses of top plate and bottom plate. My concerning cross section patterns are ...
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2answers
480 views

Does a concrete slab (deck) cause compressive load in a wall beneath it?

Let's say you build a square reinforced concrete deck at height of, say, 3 meters, with the deck supported by its own steel reinforcement and by four reinforced concrete piers (call them, A, B,C, and ...
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2answers
464 views

Buckling of a cantilever with midway support

I'm trying to understand the implications for buckling and column sizing in the drawings below. A 3000mm 120x60 RHS steel column supports a 350mm horizontal steel beam. The column base and right side ...
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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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2answers
559 views

Solid mechanics: Deflection of a rectangular elastic membrane

I am trying to solve for the deflection $w$ of a rectangular membrane with tension $T$ acting on two opposite edges. These two edges are fixed i.e. $w = 0$. The other two opposite edges are free. The ...
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1answer
81 views

Can the thickness of a guard post be derived purely from energy principles?

Consider an ordinary staircase with a banister rail supported by a wall at one end and a steel post of constant profile at the other end. The base of the post is embedded rigidly in the fabric of ...
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1answer
935 views

Composite beam calculation

I'm building a shelf out of an Oriented Strand Board (OSB-3), reinforced with steel strip attached to it's bottom side. Please check my calculations for deflection. The OSB thickness is $h_{OSB}=18 \...
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3answers
698 views

Tolerance for Beam With Cope End

I need to have some beams fabricated with copes on the ends. They will be set on top of existing steel trusses, and used to replace undersized purlins to shore up existing rafters (hence the need ...
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2answers
322 views

What does it mean when actual member reaction is 100% of allowed?

I received construction documents for an extensive residential remodel and looking at the engineering there's a glulam drop beam with a calculated member reaction that is 100% of allowed (3965 lbs @ 5 ...
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0answers
51 views

Axially Distributed Load [closed]

Given a beam ($\rho, A, l$) rotating with angular velocity $\omega$, find the maximum stress in the beam and its location. I think the maximum stress occurs at the base, because the resultant force ...
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1answer
570 views

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 ...
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1answer
2k 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,...
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1answer
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Strength of a Vertical Round Aluminum Tube with load cantilevered off it?

Can a vertical round tube safely support a cantilevered arm mounted near the top of the tube? ROUND VERTICAL TUBE: 6061 Aluminum 2 inch Outside diameter 0.25 inch wall thickness 3 feet height ...
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1answer
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How determine the compression of a beam with a concentrated end load in the x axis?

I'm studying Electronics Engineering so I have almost no background in mechanics, just a little of statics and dynamics. I have recently started an internship in an investigation center where they ...
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3answers
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Is it possible to convert uniform loads to point loads?

I want to perform a structural analysis on a portal frame using a finite element solver to get a displacements and reactions for a load. The software library only accepts loads applied to node, not to ...
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1answer
50 views

Evaluating replacement pulley axle strength

Repairs... My garage door has counterweights, and the weight of the door is connected to the counterweights with a steel cable which runs over two pulleys. The original (cast iron) pulleys had needle ...
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1answer
929 views

Maximum deflection of a beam with both ends fixed and distributed load

I'm designing a part, and I'm trying to figure out what distance a slot should be from the bottom of the part. For simplicity in analysis, I'm approximating the region between the bottom of the slot ...
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3answers
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Why do we assume the moment is zero when analyzing a simply supported beam?

When calculating the reactions of a simply supported beam under any type of loading we assume that the moment about the reaction points is zero. What if our assumption is wrong and in actual practice ...
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336 views

Energy of a 3D Timoshenko beam

I am interested in the kinetic energy T and the potential energy U of a three dimensional Timoshenko beam. For a 2D Timoshenko beam the energies read: $$ T = \dfrac{1}{2} \int\limits_o^l \left( \rho ...
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1answer
149 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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1answer
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What is the mathematical derivation for shear center of a beam?

For me, it's a bit hard to imagine where shear center can be, and what purpose it serves. The definition I found online is very vague: Shear center is defined as the point on the beam section where ...
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1answer
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Beam Reaction Problem With Hinged Joints

The problem was assigned in my Structural Analysis class, and I am having some difficulty with it. My professor said the problem is "very easy" if we just think about what the fixed end moment on a ...