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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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Aluminum rivet used to join stainless steel and aluminum sheet

I am using Aluminum pop rivets to join stainless steel and aluminum sheet together. I am aware of the galvanic corrosion risk in this situation. Are there any other risks the joint may face over time ...
Prabhakar Pandey's user avatar
1 vote
4 answers
3k views

Tension cable underneath rafter tie?

I just bought a new property with a large garage and I'm curious about the roof structure. The roof structure is supported entirely on the front/rear walls using rafter and collar ties. The rear wall ...
ryan's user avatar
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2 votes
2 answers
514 views

Should we use Hooke's Law (that linearly relates stresses to strains) if the stiffness of body is changing during deformation?

Assume I have a slender cantilever beam, fixed at one end and force applied on the other. Now, during the deformation, we know that the beam's stiffness is going to change and the force-displacement ...
Rameez Ul Haq's user avatar
0 votes
3 answers
93 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 ...
Larsa se eidaklaxtarsa's user avatar
0 votes
2 answers
132 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.
RCristianL's user avatar
0 votes
2 answers
614 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 ...
Harshit Rajput's user avatar
0 votes
2 answers
102 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 ...
Rameez Ul Haq's user avatar
1 vote
4 answers
103 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 ...
radoslav006's user avatar
1 vote
2 answers
1k 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 ...
Fedele Nacucchi's user avatar
1 vote
1 answer
193 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 ...
Share thy thought's user avatar
0 votes
4 answers
158 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 ...
Larsa se eidaklaxtarsa's user avatar
2 votes
0 answers
57 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 ...
Daniel Castro's user avatar
1 vote
2 answers
47 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 ...
Bernard's user avatar
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1 vote
1 answer
170 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 ...
Steve Feeds's user avatar
1 vote
2 answers
340 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 ...
S. Rotos's user avatar
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1 vote
3 answers
137 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 (...
ddofborg's user avatar
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0 votes
1 answer
226 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)...
Kumar's user avatar
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0 votes
3 answers
3k 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 ...
Justin E's user avatar
1 vote
3 answers
2k 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, ...
Lucas Wu's user avatar
10 votes
5 answers
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 ...
B Burnie's user avatar
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1 vote
1 answer
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 ...
T L's user avatar
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1 vote
3 answers
1k 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 ...
Aecarvalho's user avatar
0 votes
0 answers
41 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'...
SSan's user avatar
  • 101
3 votes
1 answer
21 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.
SSan's user avatar
  • 101
1 vote
2 answers
872 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 ...
some dev's user avatar
1 vote
1 answer
117 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 ...
John M.'s user avatar
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2 votes
4 answers
378 views

Bending moment calculation

Considering all the variables are the same, how to rank these connections from highest to lowest bending moment?
SSan's user avatar
  • 101
12 votes
7 answers
8k 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 ...
Mat NX's user avatar
  • 265
0 votes
1 answer
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 = ...
gx6336's user avatar
  • 35
2 votes
0 answers
52 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 ...
Hunter's user avatar
  • 79
0 votes
2 answers
3k 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 ...
DerekOS's user avatar
  • 19
2 votes
1 answer
2k 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.
SSan's user avatar
  • 101
2 votes
2 answers
139 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 ...
Klik's user avatar
  • 247
1 vote
1 answer
49 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 ...
upstream's user avatar
  • 462
0 votes
1 answer
65 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 ...
Anivarth's user avatar
  • 139
-1 votes
1 answer
295 views

Wood Dimensional Stability

Between Glue Laminated and steel plate sandwiched between two wood beams, which one is more dimension-ally stable?
San's user avatar
  • 1
-1 votes
2 answers
116 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?
San's user avatar
  • 1
0 votes
1 answer
368 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 ...
Rafael Hurtado's user avatar
-1 votes
1 answer
45 views

Shear connections

Question: which of the three shear connections (beam/column) below will require diagonal bracing?
San's user avatar
  • 1
-1 votes
2 answers
298 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 ...
Rafael Hurtado's user avatar
1 vote
0 answers
23 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, ...
John M.'s user avatar
  • 1,033
2 votes
1 answer
123 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 ...
Robin Saunders's user avatar
2 votes
2 answers
330 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 ...
sba222's user avatar
  • 151
-1 votes
2 answers
1k 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 ...
Jon Sat's user avatar
1 vote
2 answers
785 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 ...
Justin's user avatar
  • 47
-1 votes
1 answer
116 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 ...
FinallyAnEngineer's user avatar
0 votes
2 answers
112 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 ...
upstream's user avatar
  • 462
-1 votes
1 answer
505 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 ...
terauser's user avatar
-1 votes
3 answers
65 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 $...
RandomElasticity's user avatar
2 votes
1 answer
403 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 ...
Hal's user avatar
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