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Questions tagged [materials]

Use for questions about designing, manufacturing or synthesizing engineered materials or about the properties of specific materials. Questions concerning common construction materials, such as wood, steel or masonry do not need to use this tag; use the more specific tag instead.

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1answer
21 views

What happens when you wear a hydrophobic suit and dive into water?

Do you float above the surface or you drown ?
0
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0answers
17 views

EM room shielding with DIY copper/zinc/graphite paint

I am considering a low cost but somewhat effective RF shielding for a 14 cubic meters lab room. I plan to use a mix of finely ground graphite and copper powder. Zinc would be added for cathodic ...
3
votes
1answer
46 views

Aluminum tube expansion (flaring)

Can anyone point me to a calculation or formula that would tell me what percentage an 6061 T6 aluminum tube OD should be able to be flared to, using any or all of the following: OD size, Wall size, ...
2
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2answers
66 views

Why had the Alfa submarines a titanium hull?

My limited knowledge in engineering tells me: Titanium is expensive, stronger and heavier than aluminium, lighter and weaker than high yield steel. The most significant advantage of titanium is the ...
3
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1answer
65 views

Are there any cold-expandable materials of significant expansion factor?

There are thermo-shrinking plastics, commonly used in electronics, which stay shrunk after cooling down. There are thermally expanding foams. The closest to 'expanding when cooled' I know is water, ...
1
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2answers
28 views

Difference between phase and grain in a material

I couldnt get a good explanation differentiating phase and grain.From what I understood, a collection of unit cells arranged in the same orientation is called grain.A collection of grains with similar ...
0
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1answer
32 views

LS DYNA Material Model 163, Modified Crushable Foam

Question is on the meaning of input variable TID within material model 163 of LS-Dyna 971. Definition of TID variable. TID: Table ID defining yield stress versus volumetric strain at different ...
1
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0answers
12 views

How to calculate the required thickness of a material to withstand a certain force or acceleration? [closed]

I am using a sheet of a certain material to dampen a product. Now, I have been looking at different soft dampening materials, and they're all defined by their durometer scale and other factors. ...
4
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3answers
98 views

What are some advantages of masonry over prefab for homebuilding, or, why are prefab homes so rare in the United Kingdom?

The United Kingdom has a housing crisis (see Financial Times, Shelter, The Independent, The Telegraph) and a housing quality crisis (killing 3000–15000 per year), due to poor insulation. Cash-strapped ...
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 ...
6
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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 ...
1
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1answer
51 views

What is the use of v notch in Izod charpy test

While testing the toughness of brittle material by izod or charpy test why do we provide v notch?
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0answers
27 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 ...
2
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1answer
48 views

What material is it? [closed]

I'm designing a coordinate measuring machine for my FYP. I need to know what is that black zigzag flexible cover usually made of. Is that leather, rubber or some other material? And how is it ...
2
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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 ...
0
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1answer
43 views

Which materials we can use for storing liquid nitrogen?

What are the materials we can use for the long-term storage of 30~liters of liquid nitrogen with composition and grade, along with the thickness of the sheet and storage capacity? Can we use any ...
0
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1answer
19 views

How to determine the maximum internal stress for a material under compression before brittle failure?

Let us consider a ceramic material, $\mathrm{Mg_2SiO_4}$ - Forsterite, with a sphere shape. At room temperature, the ceramic sphere is "trapped" in a matrix which does not expand (null thermal ...
1
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3answers
144 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 ...
0
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0answers
16 views

Trying to boil down real world properties of materials for a crafting system for a game, which properties should I focus on?

I'm working on a crafting system for a medieval fantasy RPG with a crafting system where the stats of the output item are determined by the materials used. Say you have a schematic for a sword which ...
0
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0answers
21 views

What plastics are commonly used for light diffusion?

I'm looking to create a mass-manufactured custom display similar to a seven-segment display found on alarm clocks. What material is commonly used to diffuse the light? The challenge I'm facing is ...
0
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2answers
37 views

What type of resin should be used to injection mold an instrument mouthpiece?

I'm designing an electronic musical instrument and need to injection mold the mouthpiece. This is my project: Multiwind. The mouthpiece needs to be safe to go in the mouth, opaque (preferably black),...
6
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1answer
53 views

Volume change during tensile test

During tensile test, why does the specimen's(let's say mild steel) volume changes during elastic deformation and does not change during plastic deformation?
0
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2answers
66 views

Methods for cutting glass

I am trying to find the easiest way to cut a thick glass pattern (glass thickness of 1-3 mm thick) without breaking. I am considering laser cutting but I don't know if I can cut glass of this ...
1
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1answer
33 views

Shape memory alloy for headphones

I have been looking a lot into shape memory polymers and alloys recently and have been wondering wether they have an application in headphones. By this I mean that when plugged into the phone the ...
1
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0answers
15 views

Phase Change Materials Charge and Discharge [closed]

Is there a way to approximate the charge and discharge time of a PCM. I understand that this is a transient process as a material melts from the outside in, but I was wondering it there a means of ...
2
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2answers
47 views

In what cases are the roughness values Rt and Ra used?

Roughness measurement instruments output those two values, where Rt is the distance between the top of the highest peak and the bottom of the lowest valley, and Ra is the average distance of every ...
0
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0answers
18 views

Type of Material | Experience Based | Reactive to Moisture

https://www.youtube.com/watch?time_continue=21&v=b-A6Hs_1SME I play baseball for my school and this device (see link) has always intrigued me. I have done roughly 10 hours of research on trying ...
2
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1answer
43 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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2answers
44 views

Why would 12L14 material be a “feature” of a work-holding flange nut?

Anyone who's spent much time in a machine shop will be familiar with the hardware commonly used for work-holding and fixtures on a machine tool. In particular, the flange nut is a common item used ...
3
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3answers
65 views

What type of stainless steels can resist 6 months under the sea?

Resist means without catastrophic corrosion here. We assume that there is no coating or anodic protection. The steel can be mirror polished and passivated. To make it more difficult, the shape is not ...
0
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0answers
31 views

Coating Silicone or FKM, with PTFE?

Is it possible to coat Silicone or FKM with PTFE? My Application: I'm using Silicone and or FKM (Viton) tubing in an enclosed system and would like to reduce the amount of residue build up within ...
1
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5answers
118 views

How to create an airtight connection between Stainless Steel and PTFE?

I have these two parts shown below, the bottom cylindrical part is stainless steel, the rectangular upper piece is PTFE (Teflon). The SS prongs from the lower part need to insert into the holes of the ...
1
vote
1answer
19 views

Heats affect on material permeation?

I know that heat affects material permeation (increasing it); but I have not been able to find much in the way of data other than biologically, on how it effects materials such as plastics. Does ...
0
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2answers
45 views

Recommendations on impermeable high temp material selection?

I'm currently looking for a tubing that can withstand 350F+, have a shore rating of less than 80A, and must be impermeable or very close to it. I've found a tubing called "Viton" which is close but ...
2
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2answers
74 views

What's the difference between tempering and aging?

The processes sound really similar; I'm asking with respect to Martensite processing. Essentially the difference between Tempered martensite and Aged martensite for Steels
2
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0answers
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Recycling materials like plexiglass, polycarbonate and dibond

I'm working on a project for a printing company with the main goal to reduce their waste. Paper products are not the issue but they also use materials like plexiglass, polycarbonate and dibond. I was ...
10
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2answers
3k views

How can a knife cut through butter?

How does anything actually cut anything, since we all know stuff is made up of atoms and molecules, which can't be touched together (It Requires Binding Energy). So how come we see things all around ...
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1answer
54 views

Can fusion be used to synthesize precious metals? [closed]

According to https://en.wikipedia.org/wiki/Synthesis_of_precious_metals, precious metals can be synthsized using fission. I think that if we found a way to do it with fusion, it would be more ...
2
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1answer
40 views

The Bauschinger effect

I have a question on the Bauschinger effect. Let's say that we have a material with yield stress $400 \,\mathrm{MPa}$, and let's say that the actual applied stress is tensile for starters. If we load ...
2
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1answer
45 views

How to calculate the swl of aluminium?

I am designing a roof rack for my car that attaches to my canopy and extends over the roof of the cab. I am deciding what size of aluminum. It would need to support me walking on it ideally (80kg). ...
0
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0answers
33 views

Need help in understanding an equation in solidification modelling

I am not able to understand the 2nd equation. These equations are to model a simple solidification of an alloy system, the equations are set on a region which is semi-liquid ( mushy region ) , The ...
1
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1answer
64 views

What is strain hardening exponent?

Hardening leads to a material being more brittle.However I can't understand what is strain hardening or strain hardening exponent.Please explain why hardening leads to brittleness also in this answer ...
1
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0answers
23 views

Why shouldn't dark area analysis be used to estimate carbon content on high carbon hypoeutectoid steels?

I had this thought with me for quite some time, that you can't use the usual formula for estimating carbon content on a Nital etched hypoeutectoid sample (DarkArea*0.77) if the steel obviously has ...
0
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0answers
12 views

How can I make a copper-iron alloy by heat treatment of a sample of steel coated with copper?

I am working on corrosion test of a steel sample coated with pure copper by using a thermal projection with an arc spraying in my graduation project. I came a cross a problem with the adhesion and the ...
1
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2answers
35 views

Young's modulus for composite auxetic material

If you look at the screenshot you will see a composite auxetic material. How would you calculate the E-modulus for it? Is it as simple as the rule of mixtures, ...
2
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5answers
69 views

How would you seal a hole in an HDPE container that's in -20C environment

I have a temperature sensor in a -20C freezer. The probe is going into a bottle filled with propylene glycol solution. I want to seal the hole where the probe is inserted into the bottle. What's a ...
1
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2answers
46 views

How do I solve for the mole and mass flow rates in a system?

I've been trying to solve this problem for a while with no success. I think I figured out that $m_1$ is $420 kg/hr$ and that $n_{3,A} = 3 kmol/h$ using the mass balance equation: $input-output+...
1
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2answers
20 views

What properties can be plotted on an Ashby diagram?

I am having trouble interpreting Ashby plots. Usually, I am given the plots with the shapes but I am asked to identify where each material (metal, ceramic, composite...) fits. Can someone provide me ...
1
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0answers
74 views

Is it possible to create a hard slick non-stick non-degradable substance? [closed]

I once read on a web page I can no longer find that corundum is a covalent network. I'm guessing that's because despite the fact that the electronegativity difference between aluminum and oxygen is ...
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0answers
13 views

Heat of Combustion, Vaporization tables

It's my first time posting on this specific forum. I hope I'm doing this right. I am currently modeling fire spreading through different buildings via FDS, but I lack the properties of the materials ...