Questions tagged [structures]

Questions relating to or the engineering application of a device that must withstand a loading via deflection, stresses, resistance to buckling, or natural frequencies.

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3answers
64 views

Is a ship a statically indeterminate structure?

We can consider that a ship is a complex implementation of forces on a beam, that a ship is essentially a beam. The support is the buoyancy force which is continuous but it takes different values ...
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2answers
41 views

Double Integration Method

How can I solve this beam. I was able to find the moments of each section, from there I need help. Please if someone could help me. The method to use is Double Integration.
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2answers
46 views

What happens when we remove the load, in different regions of the stress strain diagram of mild steel?

A: Proportional limit| B: Elastic limit| C: Upper YP | D: Lower YP Let us say, the gage length was 100mm (random, just for the sake of understanding). I know that if I unload the body anywhere between ...
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2answers
28 views

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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4answers
94 views

Mechanics: example of less mass/volume gives more strength

Lets assume we have a mechanical element from uniform material that is supposed to work in a static load conditions. Moreover lets assume there is no gravity or gravity is negligible. Are there any ...
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2answers
39 views

car steering to enter the parking lot [duplicate]

I would like to understand if a "typical" car could be able to turn in this space at the entrance to the underground garage. How can I set up my calculation? I have a 2.5 meter mouth at the ...
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1answer
45 views

How to find the reaction at the pinned support A as shown in the picture? [closed]

Please help me solve the problem. I need to know the reactions at A for both the cases as shown. Please note that E is a roller, D is a pin support , B is an internal hinge and A for case 2 is a fixed ...
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4answers
83 views

Do windows add to strength or rigidity?

A friend who repairs washing machines told me that the window adds rigidity to the front cover and compresses the gasket. Also the windows of cars act against shear forces, he said. Do you know ...
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0answers
53 views

Hencky nets/slip-line fields on the the interior of a closed domain

This is a crossed post. The equations for Hencky nets are usually solved in the exterior of some domain; typical examples are the upper half plane or the exterior of a circle. I would like to know ...
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0answers
9 views

Question regarding 2D simulation of orthogonal cutting operation on Abaqus

I'm trying to simulate an orthogonal cutting operation on Abaqus, I'm using Dynamic explicit analysis. I have defined my tool as Rigid analytical body and the workpiece is of Ti6Al4V, I have not ...
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2answers
43 views

Where to place air, water and electric cables in a composite beam [closed]

If water, gas and electrical cables have to pass through three (3) openings provided in the cross section shown in Figure 2, with tangible and scientific arguments specify the adequate opening for ...
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1answer
61 views

What Causes Asymmetrical Buckling in this structure?

I've been playing around with structural modelling on the SkyCiv platform and have created this structure, related to a project I am working on to educate myself. It is 2m wide, 3m long and 1.5m high ...
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2answers
68 views

How is any kind of structural reliability achieved if the probability of annual wind speed exceedance is 0.02?

Above is the definition of fundamental basic wind velocity from Eurocode 1. According to its instructions, wind loads on building are supposed to be calculated based on this velocity. It says that ...
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3answers
81 views

How many support beams/rods needed for a firewood storage cabinet

I am building a firewood storage cabinet which should support around 100-150 kg of firewood. The cabinet is made out of wooden boards (...
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1answer
60 views

Is it possible to use Plain Cement Concrete post for fencing?

I am in need of around 700-800 posts to fence my farm in a semi-arid area in TN state, India. In my place granite posts mined from quarries are normally used. It costs around Rs 300-400 per post(6-7ft)...
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3answers
134 views

How to derive fixed end moment of a beam fixed at both ends with a point force not in the center

So this is as far as I have gotten. The formulas written in green are the formulas that I have to find/ derive but I am hitting a wall. I know I am supposed to integrate but I am not sure where to go ...
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3answers
72 views

Hollow (rectangular) sections versus solid sections

I have an engineering competition coming up and one of the things I need to build is structure with both compression and tension members. The structure is scored based on the load held/weight ratio, ...
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5answers
5k views

Why are some public benches made with arm rests that waste so much space?

While watching a YouTube video today, I noticed this public/park bench somewhere in the USA: It looks strange to me the way the arm rests on each side are so far into the bench, wasting a rather ...
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1answer
45 views

Why isn't there yet such a thing as a "Minimum Life Module" standard and concept deployed? [closed]

Why are large companies not producing, selling and maintaining the concept of "Minimum Life Modules"? What I mean is a standardized "module" hosting exactly one human being, with ...
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3answers
103 views

How to measure the stiffness of a rectangular beam, and compare it to a triangular beam?

I'm an amateur at engineering, working more on musical instruments, and I'm often in confusion regarding what exactly constitutes stiffness of a beam for a load applied on it so it could resist ...
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0answers
19 views

Wind behavior and pattern

From the 5 options, which one shows the worse wind effect? Is it (b) because wind speeds accelerate through a gap? But how about in comparison to (c)? Or (d) due to the height and sharp corners? If it'...
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1answer
20 views

Seismic question

For a 3 stories building, in terms of seismic vertical instability which one is worse: a higher mass on Level 2 or, higher mass on the roof? Both are compared to L1 mass.
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1answer
65 views

How to determine the fixed end moment?

I was trying to compute the fixed end moment for the beam (given below) using equilibrium equation for x, y displacement and moment but there are 4 unknown variables reaction and moment at both ends ...
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1answer
49 views

Reinforce foldable table legs

I'm trying to build a table with 4 swivel legs that can be locked into arbitrary angles so that it can stand over one to three rows of storage crates in my garage: As you can see, the legs aren't ...
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0answers
52 views

Do any roller coasters actually use the brachistochrone curve?

Not sure if this is the right place to ask this. But I'm assuming roller coasters are related to engineering. I know that in theory, the brachistochrone curve is the fastest way from point A to point ...
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4answers
100 views

Bending moment calculation

Considering all the variables are the same, how to rank these connections from highest to lowest bending moment?
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6answers
6k views

Why does a gear have extra holes?

In a gear you normally have a center hole for the shaft to be put into. Why do some gears have holes surrounding that center hole? Is it for weight reasons? Does it add stability? Is it so you can add ...
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1answer
24 views

reaction of structure

all is this sturcture stable ? or structural determinate ? Let the top support as A , bottom support as B , By taking moment about A, i managed to get 10(4*4)/2 -HA(2) = 0 , HA = 40kN, HA = HB = ...
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0answers
26 views

Help sizing of lug attachment flange/plate?

Apologies for the crude drawing attached, but here goes. Given Fx, Fy, and Fz loads applied at the lug hole, I've distributed the loading into each of the 6 fasteners to size them. I've also sized the ...
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2answers
474 views

Are these horizontal timbers removable in an attic/loft?

There are 3 horizontal lengths of timber stretching across the centre-level of my attic/loft space and are attached at either end to the rafters with a single nail. I can wobble them by hand and they ...
2
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1answer
128 views

Wood beam connection

Can someone please explain why the top left image is correct and the bottom left image is not? Both of these images have the bolts on the lower half of the wood beam (tension) side.
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2answers
59 views

Is it practical to use tensile cables in a composite beam?

Many composite beams combine material that has a good tensile strength with material that has a good compression strength (like concrete and rebar). I was wondering if there has ever been a beam that ...
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0answers
28 views

When settlement criteria of a foundation is satisfied, bearing criteria is also automatically satisfied?

We design the foundations to settlement criteria than bearing correct? Because settlement criteria is stricter? I mean, can there be an example where the settlement criteria is satisfied but bearing ...
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1answer
34 views

What is the linear strain for given lateral strain?

So, I am trying to calculate the linear strain of a shaft which is under plastic deformation in yielding region. The diameter is changing from 2d to 1.5d I'm assuming that the volumetric strain is ...
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1answer
53 views

Wood Dimensional Stability

Between Glue Laminated and steel plate sandwiched between two wood beams, which one is more dimension-ally stable?
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2answers
78 views

Beam/column sizing

If a load P is applied as shown to a fixed column-beam, pinned at the bottom, should the beam or column (or both) sizes be increased to resist the load?
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1answer
131 views

Question on the determinacy of frame structures

I have been working on a program to solve frame problems, and I have used the following formula for determining whether a frame is statically determinate: $$RD=3m + r-3j-s,$$ where: $m$ is the number ...
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1answer
30 views

Shear connections

Question: which of the three shear connections (beam/column) below will require diagonal bracing?
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2answers
170 views

Unable to obtain closed system of equations using method of joints

I am currently working on some code to solve 2-dimensional truss and frame problems, and I have come into an issue with one of the problems. I need to come up with a system of linear equations that I ...
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0answers
19 views

Secure loads to gearbox shafts

I have a sculpture that is designed to rotate over 3 axes at max. 30RPM and is mounted on an aluminium disc. My plan is to use 3 of these geared steppers and secure the sculpture to the Z-axis shaft, ...
2
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1answer
56 views

Cheap but durable design for a quick-to-assemble, portable globe?

This question has a bit of an arts & crafts / DIY flavour, but looking at those Stack Exchanges made me feel it fits better here. I have no background in any of these things, so apologies for my ...
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2answers
118 views

Do the floorboards in timber beam floors have a structural function?

Timber beam floors with perpendicular timber floorboards as indicated in the drawing below are common throughout northern Europe. The floorboards are nailed onto the beams and are quite substantial ...
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2answers
91 views

What is the easiest way to regulate the speed of a falling object?

I want to design a system that allows a 1kg metal brick to fall under gravity at variable speeds. The brick initial position is 20cm above a flat table. I want to have control on the duration (to ...
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2answers
188 views

Fixed-Free End Column Design

I am currently working on a problem where I have to design a column. The structure I am currently designing currently takes the following form, When designing the column, I know that I have to ...
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1answer
40 views

Method of joints not working on simple truss, supposed to be stable and determinant

In the process of editing the question to put better pictures of my dimensions in, I realized that how I calculated my angles was incorrect, and that is why my answers were yielding inconsistent ...
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2answers
36 views

Earthquake time history analysis

Time history analysis of earthquakes for structures, is a NON-LINEAR dynamic method correct? Then why is there also something called "LINEAR response history analysis"? What is the difference of this ...
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1answer
151 views

What is the strongest structure?

I am not an engineer, but I thought maybe this could be a very old and classic problem in structural/mechanical engineering. I need to build a support structure to hold a uniformly-distributed load of ...
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3answers
45 views

How to solve a system of second order ODE from time t = T to t = 0

I have a system of second-order ODEs $$ \mathbf{M\ddot{x} + C\dot{x} + Kx = f} $$ I want to know some good numerical methods to solve this system of the equation given the initial conditions at time $...
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1answer
50 views

Calculate whether a polycarbonate plate can withstand a certain force

I need to calculate whether a polycarbonate sheet can withstand a certain maximum force. The force is an impact force on any one point of the sheet at any given time. All I have are the Young's ...
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8answers
9k views

What are those large poles for that are always in front of US stand-alone store buildings?

Screenshot of a video where they are featured in the background: They appear to have no electronics built in, such as an electric charge station, or a parking ticket dispenser or something like that....

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