Questions tagged [strength]

This is to be used for topics regarding the strength of materials, the analysis of internal forces in a body and all the governing principles which considers deformation of bodies.

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8
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4answers
19k views

Why does the stress-strain curve decrease?

This is a stress-strain diagram I have noticed that the curve decreases between points C & D and between E & F. Why does that happen? I expected the curve to always increase since the ...
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3answers
6k 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 ...
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2answers
958 views

Calculating shaft diameter

I'm designing a circular shaft that's going to carry a spread radial load of about 200kg and also transmit a 160Nm torque. I'm not very familiar with materials but what I'm guessing I'll be able to ...
5
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1answer
188 views

Can concrete lose strength during curing?

We cast a bridge's concrete deck and kept samples for concrete strength tests at 7 and 28 days. We took a test at 7 days, and the test result were over the design strength (designed for 30 MPa, ...
5
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2answers
95 views

Could a vacuum tank ever be light enough to be boyant in air?

Given futuristic materials, could a structure ever be strong enough to contain a vacuum, yet light enough to provide buoyancy under standard atmospheric pressure? Obviously "futuristic materials" is ...
5
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1answer
101 views

Would a partial space elevator work? [closed]

Background The normal space elevator (that reaches from the Earth's surface to a counterweight beyond geostationary) needs a material that's strength/weight ratio is better than any material we have ...
4
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1answer
128 views

What methods are there to test the flexural, tensile and compressive strength of concrete?

The only one I know is the three point bending test for flexural strength.
4
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2answers
463 views

How to provide lateral support for adjacent masonry during installation of steel UC in an old cavity wall?

I've got a structural engineer ready to provide calcs on this job, but there is a specific aspect where I'd like a heads-up what the normal approach would be, before I raise it with him, in case he ...
4
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2answers
240 views

How to determine tensile strength while the normalised tensile strength is known?

I try to design a shaft with yet unknown diameter, i know the distribution of forces and stresses (shear, torsion and normal) in/ along the shaft. I need just one more parameter nl. the tensile ...
3
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2answers
75 views

Strength of Plastic Underwater Domes with various thicknesses

I'm currently researching the strength of domes underwater and I went down the rabithole of material science. The basics of this research (or though experiment) is to bring a dome filled with air to ...
3
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1answer
149 views

Distance of Pivot from the Rear axle

I am designing an NSAM crane. I have encountered the following issue when designing the vehicle: Generally the pivot(or the point about which the NSAM crane rotates) is in the center. But from two ...
3
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1answer
101 views

How to compute core stress in honeycomb structure?

Assume I have a honecomb(sandwich) panel under distributed normal load. Each edge of this panel is simply supported(pinned) as on the picture below: The problem is how to find the core stresses σ-z (...
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4answers
103 views

Which post would be stronger?

Just a quick question for you. Well hopefully. A contractor has installed a retaining wall with colorbond fence on top. In the contract he stipulated that he would use 65mm x 65mm x 1.6mm powder ...
2
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3answers
834 views

Springback after a plastic deformation

Before the yield point, the deformation is elastic, and then it is plastic. But what happens to the elastic 'part' of strain after the load is removed? Is it retracted fully or partly, and how does ...
2
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2answers
1k views

Is strain energy the same as potential energy, or something differen?

Sorry for this stupid, basic question. But I got hung up on it. We know from Clapeyron's theorem that the strain(internal) energy of an elastically deformed body is equal to half the work $$ U=\...
2
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2answers
56 views

Beam buckling criterion?

If I have an I beam which I subject to some bending load, how can I calculate when the thinner middle part of the I beam will buckle? I though I could use Euler's critical load formula here, but it's ...
2
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2answers
469 views

Fillet weld strength calculation

I have 2 plates that are fillet welded to each other. How can I determinate the max force the weld can take before it cracks? The plates are only welded on one side because the other side is not ...
2
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1answer
65 views

“The monofilament wire has a tensile strength of 18 kg” What does this mean?

I am used to strength being measured in units of stress, such as pounds per square inch, or Pascals. I am assuming what the author is trying to say is, "this filament will break when holding 18 kg," ...
2
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1answer
68 views

Strength of bolts

I was wondering if it'd be a good idea to attach a 10kg load to the end of a movable steel rod by fastening it with just one M5 bolt. Looking at Misumi's datasheet, M5 (Class 10.9) has an allowable ...
2
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1answer
81 views

Resolution of forces and state of stress at a point

Is resolution of forces similar to expressing a vector as a linear combination of some other vectors in linear algebra? Similarly, Is the state of stress at a point in 3D similar to expressing the ...
2
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1answer
381 views

Arc welder? Cheap welding device for chainmail/chainmail jewelry

I'm hoping this is the correct StackExchange for this question/request for advice. I'm looking to buy a welder to introduce me a little to welding, my main use-case right now is the hobby projects I ...
2
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1answer
50 views

Low-tech ways of assessing relative strength of a material (yield point)

I want to compare strength of a metal before and after heat treatment, to assess to effectiveness of that treatment. (See my previous question, Aluminium softened by brazing. How to harden?). ...
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0answers
8 views

Is inverse hall-petch relation valid crystals larger than nanocrystalline?

The image shown here is of ceramics, where they varied the grain size and measured the strength. For example, let's take Al2O3. There we observed that strength first increased from 3 μm to 95 μm. But ...
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0answers
35 views

Column Buckling Boundary Conditions — Welded Tubing Practical Application?

I'm trying to do some calculations for a personal project. I'm trying to understand column strength / buckling. My questions relate to Effective Length Constant, which is based on Boundary ...
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0answers
11 views

How do I relate Grab Strength and Grab Tear to the real world?

I'm looking at a spec sheet for a high density polyethylene woven fabric and I'm seeing the following parameters on it Tensile Grab Strength: Warp 155 / Weft 170 - tested ASTM D-5034-09 Grab Tear:...
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2answers
60 views

How to strengthen existing masonry vaults and domes? [closed]

I would like to know what methods are usually used to strengthen existing masonry vaults and domes, especially the ones called Catalan Vaults, and how to design them. Thank you in advance.
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3answers
85 views

Beginners material science for handling a load

I’ve got a reasonably strong grasp of Newtonian mechanics, but as far as material science goes I don’t know which of the many material properties I need to use to solve my problem: I’m trying to mount ...
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1answer
248 views

Definitions of strength?

Can tensile strength be the same as yield strength? Can Flexural Yield Strength be related to the yield strength of a material in any way?
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1answer
175 views

With which parameter can you specify whether a metal is ductile or brittle

I have to do a durability approval of feather key (shaft-hub connection) and the formulas are dependent if the shaft respectively the hub is ductile or brittle. But what is the decision about to say ...
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1answer
68 views

Boron Carbide Shattering a Bullet

Does anyone know how this works? I hypothesize that the reason that the bullet shatters is that boron carbide is much harder than the copper of the bullet. Does anyone think that this may be made into ...
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1answer
599 views

What causes shear force?

Most of resources I've been reading don't explain the scientific reason for the existence of shear force. Most resources just teaches how to solve problems and about properties. Nothing goes deep (not ...
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1answer
46 views

Stability of 3D-printed mask after sterilisation

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6797553/ https://www.hatchbox3d.com/collections/pla We are 3D printing masks that need to be used by medical staff treating COVID19 patients. The first ...
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1answer
26 views

Is there any way to improve the strength of simple at-home aluminum/copper/brass castings (sand-casting hammers)

I'm just getting-into melting-down cans to make aluminum-based slingshots, hammers and the like. In my ignorance I didn't realize that copper/brass were also things that I could process which has ...
1
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1answer
105 views

Locations of max stresses in a circular beam?

If a torque and axial force is applied to a beam with a circular cross section, where along the cross section of the circular beam is the location of the max shear stress, max bending moment, max ...
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1answer
108 views

Most efficient fillet design given an envelope (for stress)

If one has a specified allowed X length and Y height, into which a fillet can be placed to reduce stress concentrations, is there an equation which can be used to determine the optimal shape of the ...
1
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1answer
54 views

Mounting outdoors camera using aluminum 5052

I designed a simple U shape 2mm sheet metal bent mount for a 4kg outdoors CCTV camera. The mount was accidentally produced from 5052-H32 Aluminum instead of 6061-T6. Is it common to use 5052 ...
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0answers
57 views

Analysis Of Planar Frame Using Hardy Cross Method (Moment Distribution) With Sway

The image shown below is a sketch of the structure/frame that I am attempting to analyse using the Hardy Cross (Moment Distribution) Method. I need to find the bending moments, axial forces and shear ...
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0answers
20 views

Generating random samples for some concrete structural characteristics [closed]

I want to test a program that performs FRP concrete structural strengthening calculations according to a particular design code. As inputs for these calculation, there is existing concrete cross ...
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0answers
24 views

Force applied on board from bed of nails [closed]

For testing a new manufacturing process of PCBs in our company, we design 2 bed of nails. One bed will have about 80 nails while the other about 180. Both beds will use the same fixture that will ...
1
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0answers
348 views

Will drilling a hole in a pane of glass reduce it's structural integrity?

I've got a glass box that measures 900mm x 450mm x 450mm. The width of the glass is 6mm thick. If I drill, cut, or grind a small hole in/through one of the faces; will it significantly affect the ...
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0answers
408 views

Cement-Filled 6" PVC Bollard [closed]

My next door neighbor's car backed into my wooden fence and knocked down a section. I want to protect the fence from a future accident. A steel pipe filled with concrete would cost more than PVC. A ...
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4answers
5k views

Is it safe to stand on a toilet bowl?

As most westerners know well, ceramic toilets are designed to be sat on, even by those who are quite overweight. However, since it's customary in Asian countries to squat when using the toilet, some ...
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3answers
226 views

Surface Finish and Strength

Does surface finish affect steels strength properties? If so, how does strength increase or decrease with the type of surface finish applied?
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2answers
188 views

Thick walled cylinder theory - Stress/strain in ballooned out tube

I want to work out how much I can expand a piece of rubber tubing before it ruptures. The wall is 0.75mm and the ID 5mm. Hence I am working out the stress/strain from thick-walled cylinder theory ...
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2answers
51 views

Material for car mounted fire extinguisher bracket

Don't try this at home. I am taking personal responsibility for what happens in my car. Hi all, I recently purchased a fire extinguisher for my car (it weighs 1.5 lbs or 0.68 kg). I browsed the ...
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1answer
5k views

Maximum compressive force for pipe vs solid cylinder

If I have a pipe with external radius R and internal radius r. Maximum compressive force will be given by the same formula Fmax=σS as for cylinder or different? where $S = πR^{2}-πr^{2}$, and σ is ...
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2answers
472 views

Do I understand column buckling?

I'm going to make such a stool: Originally it's made of thick plywood, and I want to switch to a thinnest possible OSB to make it as cheap and light as possible. It's a bar stool of 70 cm height, 33 ...
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2answers
75 views

What is the actual stress in a certain point in a body?

I'm reading my book on strength of materials and it says that the stress in a point depends on the orientation of the section that we are observing, and since there are infinite number of section that ...
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1answer
423 views

Along which direction is the area moment of inertia taken in bending moment equation?

Is it in the same direction of the applied load or in the co-planar perpendicular direction to the load applied?
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2answers
41 views

Need advice: Estimating the compressive yield strength of abdominal tissues from the data of its rigidity or stiffness constant

I am doing research on biomedical device development, and focusing on devices that work on grasping tissues in the abdominal area. I need some help with applying the concepts of material strength to ...