Questions tagged [structural-engineering]
Questions related to the integrity, design requirements, or analysis of structures.
566 questions
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Combining response spectra
I have a question regarding response spectra and its use within dynamic analysis.
Assume that a load combination that a component is subject to is the result of two events: A and B. If each event, A ...
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1answer
58 views
What can a licensed Mechanical Engineer do in the civil/structural field?
When I was younger, I had interned in a civil/structural engineering firm specializing in bridges that had many PE civil engineers on staff and a couple licensed mechanical engineers.
Now as a soon-...
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2answers
68 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 ...
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37 views
Assumptions to neglect shear stress in a sectional area
Which assumptions do I need to simplify or neglect the two shear stresses of my stress tensor for comparing two sectional areas in relation to their stability? And do you have any reference for such ...
2
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1answer
48 views
Help with cantilever table top questions
I'm hoping someone can help me with some questions to know whether or not the table can be supported by this design and how to calculate the length of the support runners and the width necessary to ...
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1answer
58 views
Equation of the parabolic suspension bridge cable when the deck mass is known
I'm reading the derivation of the equation of the hanging catenary from Wikipedia:
https://en.wikipedia.org/wiki/Catenary
In the same article the parabolic equation governing the shape of the main ...
2
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2answers
26 views
Is is possible to use singularity function to expresse the horizontal forces ?
I know how to translate torques and vertical forces into singularity functions, but may i also express the horizontal forces with singular function? if yes then what would be that expression?
Here ...
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3answers
106 views
Why aren't there moments in truss bridges?
One of the assumptions we make when analyzing truss structures (method of joints for example) is that all the components are assumed to experience only compressive and tensile forces, not bending ...
2
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1answer
48 views
Shear forces along a beam using singularity functions
$\newcommand{\a}[1]{\langle#1\rangle}$
As you can see, the left end of the beam is fixed, and a distributed load is applied to the beam. I calculated the shear forces by conventional means, but when I ...
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24 views
structural radius for strain evaluation - Propeller Design
What is 'structural radius for strain evaluation' in aircraft propeller design?
2
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3answers
165 views
Minimum thicknesses of an elliptical cylinder pressure vessel
For pressure vessels in the shape of circular cylinders, we can use $\sigma_{hoop}=\frac{pr}{t}$ to find the minimum skin thickness by setting the hoop stress the maximum allowed value, and then ...
2
votes
1answer
51 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
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2answers
64 views
Why is this structurally sound?
While visiting Vancouver, Canada recently, I noticed there is a lot of construction for apartments and condos. Attached is a photo of one of many of those sites, and at these sites, I noticed ...
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2answers
45 views
For a building on a slope, should the grounded earth lightning protection be downhill or uphill from the structure?
Would it be best to place the earth protection (the copper spike) for a building on a slope downhill (A) or uphill (B) from the structure? Assume that lightning is most likely to strike at (C), the ...
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2answers
37 views
Solar Array Frame Design / Statics Design Problem
I need some help with a statics design problem. I am tasked with designing a solar panel frame to mount on a building and am the only engineer on staff so I don't have anyone else to ask the simple ...
6
votes
3answers
796 views
How does the strength of a square tube depend on the side size?
There are two square tubes of the same length, material and wall thickness, one being 40x40mm, the other 20x20mm. How does their strength against bending compare?
On the one hand, the cross-sectional ...
2
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1answer
29 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 ...
2
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0answers
41 views
Difference between direction of ramming in hydraulic press?
In Printed circuit board/Plywood lamination Hydraulic Press machines (seen here).
The ramming action comes from bottom in all the machines I saw so far. For such action from bottom, excavation has to ...
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2answers
62 views
irregular shape basement as part foundation for two story timber frame house
A 3 m deep basement has a two story timber frame house above.
They share a side, however both have parts "outside" of the other, as can be seen in the sketch below. The red dash is the basement, ...
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0answers
27 views
20g 11 msec shock
Is there any reliable procedure to estimate a constant acceleration acting on a body (for structural calculation) in case it is subjected to a momentary shock?
I'm assuming it is possible to ...
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0answers
27 views
How to span a 28' gap, preferably with wood
I am building a temporary structure in a windy area (this is for Burning Man). We are essentially using 4x4s that are embedded into the ground (hard clay floor) that are spaced apart by 2x6 rafters. ...
2
votes
1answer
23 views
Shear strength polymers
I was looking for some shear strength properties of common polymers/plastics.... I have not found any usefull information yet. I know polymers aren't that linear elastic, but I expected to find some ...
2
votes
1answer
77 views
What is the engineering term for the gear style articulated arm
You loosen a screw (knob) and then move to the angle you want and tighten.
I need to know what the engineering term for this part is.
Thank you in advance
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3answers
47 views
Excavation near existing structure
I am thinking of building a house with basement next to some existing structures. Are there rules of thumb on how closely/deeply you can excavate next to an existing structure? By moving farther away ...
3
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4answers
177 views
Is there any need to consider loading sequence in construction stage for structure analysis?
Load sequence in phases can be considered applying the self-weight load only to the story added in the appropriate phase.
Assuming that the material will not go into yield stage ( will always be at ...
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0answers
26 views
why there is overestimated or underestimated occured in machine learning prediction?
I have these 5 cases I considered to validate my ANN model
all parameters included
ave thick, plate width, plate length, initial thick, young modulus, ultimate strength, yield strength
parameters in ...
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3answers
55 views
What is the good reason if the curves between two results are not similar?
According to my results, I can have this curves.
And somehow in this figure, it is not pretty much similar,
What can I say if it is asked why I still want to use the FEM results?
Or how can I ...
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0answers
34 views
strength of eggshell
It is a known fact that beams and spheres have the ability to carry relatively high loads.
Beams are seen in bridges and other structures even since the days of ancient roman architecture.
Spheres ...
2
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1answer
37 views
Timoshenko Beam Theory for Quasistatic Cantilever Beam: Shear Term
I'm trying to determine the effect of shearing force on the deflection of a quasistatic cantilever beam. In his book, Theory of Elasticity, Timoshenko added the following term to the deflection:
$$\...
2
votes
2answers
31 views
How to find a beam for my (simple) application
I have a spanof 9m that I bridge with a (as yet unspecified) beam. From this beam hangs a load (a pipeline), right in the middle, of 4.295 kN. The beam is simply supported. I want to use an IPE steel ...
17
votes
1answer
3k views
Why are truss bridges the way they are?
Just by taking a train ride across my home city I can see truss bridges like the one in above picture everywhere. There are numerous variations, but the most common design seems to be this. But why ...
4
votes
3answers
75 views
Do scaled models reflect strength characteristics of full size
Lets say you want to build a bridge out of carbon fiber. This has never been never been done before, and it's super expensive stuff. So your goal is to use as little material as possible, but ...
10
votes
4answers
883 views
Why does column buckling occur when the load is parallel to the column?
I'm studying Euler's work on structural engineering from a book out of curiosity and it is mentioned that he developed a mathematical theory describing the buckling of columns under a parallel load (...
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1answer
28 views
How buildings 3D model is created [closed]
Suppose I have a rough 3d model of a building created it some CAD software. Now I want to change some portion of the model based on the following factors
Lighting
Energy consumption
Structural Load
...
0
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1answer
32 views
FEA; overstressing over crushing for glass container
How do I prove that during a loading session of a glass container, between two failure modes, overstressing or buckling (crushing), which will happen first via FEA? Is there any scientific way of ...
2
votes
2answers
50 views
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 ...
1
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1answer
53 views
Debugging Ansys ACT C# Extensions
I'm using the Ansys ACT Api with C# to create an extension for Ansys (Mechanical).
When developing the extension I need to build a dll file from C# code (using Visual Studio). My problem is that ...
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0answers
15 views
Difference Between minimum steel required in Slabs and Shear Walls
My question is very simple, I need to know why the minimum reinforcement for slabs is less than the minimum reinforcement required in Shear walls?
What are the criteria and reasons to set minimum ...
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0answers
24 views
Will screed on plywood do instead of beam and block, to replace a floor?
I'm gutting and redoing an older house (early 20th C, ordinary suburban terrace house, London UK).
I'd planned beam and (dense) block for the upstairs structural floor, for a few reasons, and already ...
0
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1answer
40 views
Should I apply Force or Pressure, Ansys Static Structural
I am working on a project where I must find the maximum principal stresses on an object subjected to impact loading condition. I know the velocity of the object (the one which will hit the test object)...
4
votes
3answers
84 views
Wind load of panel
I am planning a prop for a marching band show and I want to determine how to best address the challenge of the wind blowing it over. This is definitely not my area of study and I am hoping for some ...
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3answers
131 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 ...
1
vote
1answer
49 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 ...
1
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2answers
62 views
How to determine how large each terrace should be on a multi-level retaining wall?
I am making a concrete sleeper wall and am unsure of the current structural integrity (I am not a civil engineer) specifically regarding the width of each terrace.
My retaining wall will be made ...
4
votes
1answer
62 views
How do you convert “kps” to Pounds per Square Foot (psf)? [closed]
I'm looking at a soil bearing capacity report, which has a column labeled "kips" and the values are followed by "kps".
A "kip" is 1000 pounds, but I'm not sure how to convert from "kps" to psf.
The ...
2
votes
1answer
37 views
Structural mechanics
Ques: I have a question regarding solid mechanics and plate theory,is 2 layer plate means laminated plate or simply refers to as a plate?
4
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3answers
40 views
Shear force expression for singly supported triangular load
From equilibrium: $$C_y = \frac{w_0L}{2}$$
And the load is given by: $$w(x) = \frac{w_0}{L}x$$
Thus the expressions for shear and moment are given by: $$V(x) =\int{-w(x)dx}=-\frac{w_0}{2L}x^2 + C_1\...
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1answer
53 views
What is the maximum deflection and bending moment of a hinged hinged beam? [closed]
It is not a simply supported beam with one end hinged the other end with roller support. I am working on both the ends hinged beam. i.e at the two ends only rotation about z axis is allowed and all ...
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0answers
31 views
What type of steel is the Golden Gate Bridge made of?
What type of steel is the Golden Gate Bridge made of? What metals does the alloy consist of? Where and how was it created? Does the type of steel used in the bridge have a serial number? Is the type ...
0
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1answer
152 views
How would I find the Second Moment of Area of a Parallelogram?
How would I find the second moment of area of a parallelogram, as shown?
