Questions tagged [beam]

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

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Ceiling mounted punching bag without compromising structure or floor above

This question is regarding the safest way of installing a heavy punching bag of 100 lbs from the basement ceiling. Above the basement ceiling is a wood floor. The goal is to sleep soundly at night ...
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1answer
81 views

How does the superposition principle relate to Bernoulli-Euler and Timoshenko beam theory? [closed]

I have a shaft with a bearing in each end, and a large eccentric mass covering the entire "free length" of the shaft. The attachment of the eccentric mass is done using heat shrinking. Without ...
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3answers
1k views

Transfering moment through internal hinge

My professor says, the internal hinge can not transfer moment: But can we calculate $\Sigma M_A=0$ for whole beam ( without cutting it or something) this way?: $\Sigma M_A=0 ===\Rightarrow M_A+(D_y ...
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1answer
57 views

Base Support for a Tree house

I am building a tree house in my backyard and it is going to be relatively simple. There are no parts that require drilling into the tree. The whole house is propped up by four 4x4 wood supports. I'm ...
4
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3answers
87 views

Natural frequencies of an orthotropic bending beam with circular cross-section

I am trying to find an expression for the natural frequencies of an orthotropic bending beam with a circular cross-section. I have tried searching for some literature on this, but have so far been ...
4
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2answers
3k views

Multiple Varying cross section beam deflection

How do we calculate the deflection of a cantilever with two or three cross-sections, and different forces acting at the end of each section?
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1answer
195 views

Beam Span for Outdoor Shelter [closed]

I'm building an outdoor shelter and I'm wondering what would be: The maximum beam span for the type of wood/material used such it can support the roof weight and not sag in the middle, Suggestions on ...
3
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1answer
122 views

Skewing of joints using virtual work

Given ist the following framework: $$E=210 \frac{\text{kN}}{\text{mm}^2}$$ $$ EA \to \infty $$ $$ I_1 = 80000\text{cm}^4 $$ $$ \frac{I_1}{I_2} = \frac{3}{4} $$ $$ I_3=I_1 $$ Using the principle of ...
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2answers
155 views

Engineering mechanics(statics) [closed]

I don’t get how to get the answer to part e. Should we assume reactions at A and B in all three figures are same? If so, why?
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2answers
812 views

Beam deformation under trapezoidal load

Can somebody help me find the equation for the deformation of a simply supported beam under trapezoidal load (with intensity Q1 and Q2, at starting point X1 and end point X2)? I am trying to find it ...
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0answers
1k views

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 ...
2
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3answers
57 views

Support columns inside metal tubing

Does structural metal tubing (e.g., either as HSS, or in space frames, or even motorcycle/bicycle frames) ever come with any small metal rods or columns inside of the tubing itself? While it might ...
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0answers
759 views

Simply Supported beam with multiple point loads and distributed load [closed]

How can I solve this problem using FEM (longhand calculation)? I want to find deflections at each load point. This is not a homework problem. This is related to a project that I and my brother is ...
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1answer
2k views

Transfer of moments in beams with internal hinges

We have a beam with 1 internal hinge just like the picture. We know the internal hinge can not transfer moments between AB and BD. We know the 30 kN force makes some moments on BD & AB. If B (...
4
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1answer
146 views

Why are steel I-beams mostly symmetrical?

From what I understand most types of steel are strong both in tension and compression, yet they are still usually significantly stronger in tension. Suppose a common I-beam supported on both ends and ...
4
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3answers
4k views

Are the points of inflection and contraflexure the same?

In theory of bending of beams, often these terms are used. There are no clear definition present. Most of them contradicting. Which of the property(bending moment and shear force) is zero in which ...
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1answer
278 views

How to deal with inverse distributed load ramp starts and ends somewhere along the beam?

I know how to solve it by moment line methode but i want to use singularity function here and i'm very confused. My strategy consist of writing the correspond singularity function for each element but ...
3
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3answers
117 views

Why in the construction of power transmission towers , the rods are hinged oblique? [closed]

I know if a rod is hinged at its two ends and if there is no load act upon it along its length then the forces exist only along its length but i don't see how this characteristic comes into play ?
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0answers
61 views

How to design a shelving unit out of McMaster Carr Struts? [closed]

I apologize for the complete beginner question. I'm an Undergraduate Research Assistant trying to design a shelving 8'tall by 10' Long, 4' wide shelving unit to support about 200 lbs. I'm designing ...
4
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1answer
99 views

Deformation of two perpendicular beams with parabolic properties

I want to calculate the deformation of the following structure: I have numbered the vertical beam 1 and the horzontal beam 2. The hight of beam 2 is given by: $h(x)=h\sqrt{1-x/L_2}$ So I thought I ...
2
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4answers
128 views

Moment and Torque at a Single Point

As far as I know, moments/torques occur when forces applied are not in line. However, I often see moments/torques being applied at a single point in free body diagrams. How can moment/torque be ...
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2answers
6k views

how to solve internal hinge problem with loading given on hinge [closed]

how to solve internal hinge problem with loading given on hinge
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1answer
993 views

Why are the support reactions of the two pin-connected members different?

Can someone please explain why the support at C does not have a vertical reaction force while the support at E has? Doesn't the support at C have the same kind of pin connection as the support at E?
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0answers
279 views

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 ...
3
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1answer
61 views

Is there a need to consider the moment generated by horizontal water pressure in a pool?

Suppose there's a pool which is supported by 4 beams (Perimeter beams)and 4 columns. When designing the beam should we consider the moment generated due to the horizontal water pressure? (I'm using ...
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1answer
93 views

Structural engineering: Would I need a beam for this? [closed]

If I was designing a simple gabled house with a 21 ft vaulted ceiling as the peak of the roof, and the house was about 32 ft x 40 ft with no load bearing walls (other than the 4 exterior walls)... ...
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1answer
2k views

Reinforcing beam and slab with correct steel bar structure

This question might look silly. I am not knowing the correct engineering terms to use in this question. I am trying to explain using the words what I know in English. We have been hired some ...
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1answer
102 views

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. ...
4
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2answers
2k views

Round beam deflection under its own weight

I'm trying to calculate how much simply-supported round beams of several materials and diameters deflect under their own weight plus an additional weight in the middle. I know the material densities ...
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2answers
255 views

How to analyse a beam considering P-delta effect?

I want to do some analysis of an axially loaded simply supported beam considering P-delta effect. I set up a non-linear load case and apply axial load to it. Subsequent analysis of live load and dead ...
2
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2answers
1k views

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 ...
2
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1answer
97 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
56 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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2answers
127 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 ...
3
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1answer
85 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
2k 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
364 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
1k 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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2answers
3k views

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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0answers
172 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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0answers
65 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 ...
6
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1answer
685 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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2answers
619 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
230 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
87 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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3answers
90 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
2k views

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
994 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
785 views

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 ...
3
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2answers
74 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? ...