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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.

2
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1answer
56 views

Why are vacancies in solids called as equilibrium defects?

My professor, when discussing about Random Walk model during diffusion in metals said that "Vacancies are equilibrium defects but dislocations are not". I could not understand why. Why is it so?
1
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1answer
42 views

How to track parts through high-temperature oven and abrasive treatments?

I have been thinking of a problem and I would like to brainstorm about it with the community. Scenario: Machined parts going through termal treatment in an oven and further abrasive treatments. ...
1
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0answers
32 views

Buckling of composite plates help

I am trying to write code for the buckling of composite plates using the Ritz approximation but I can't understand something. According to Reddy (Mechanics of laminated composites), this is the ...
0
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0answers
30 views

Instron Test Profile — Failure when steadily dropping the load

I'm working on an Instron 5969 tester, and I'm trying to measure the residual strain in materials within their elastic zone. I'm using the test profile, which allows me to stretch the material a ...
0
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1answer
44 views

Sizing crumple zone for multi-vehicle collisions

I need to size bumper beams for the crumple zone of a very lightweight vehicle. Together with the driver, the vehicle will weigh 300kg. Sizing the beams for a single-vehicle collision against a ...
0
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2answers
73 views

Longitudinal and transversal strain

The Poisson ratio of the material equals 0,33. If I load a cube or a cylinder that is fixed at one end with compression force in ANSYS I can confirm that the ratio is 0,33 by dividing the lateral by ...
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0answers
7 views

How to Calculate the Speed Ratio between two rollers (overdrive of take-up roller) to provide a required Tension web tension

I have a web feed system with a re-winder and I need to apply a tension to the web. I have a driven roller and a take-up roller. I need to calculate how much overdrive to supply to the takeup roller ...
0
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2answers
92 views

Distribution of energy absorption in inelastic collision

Object A has mass $m_A$, and is travelling west with velocity $v_A$. Object B has mass $m_B$ and is travelling east with velocity $-v_B$. The objects collide in a perfectly inelastic collision so ...
2
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1answer
57 views

Can isotropic materials become anisotropic under elastic deformation?

Are there solid materials that begin as isotropic materials (i.e. isotropic elastic parameters) in their natural (i.e. unstressed) state, but that become anisotropic under sufficient stress/strain? ...
3
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1answer
29 views

Is there a reason why both plasticizer and vulcanizing agent are needed during processing of rubber?

According to this Wikipedia page, vulcanization is an important process to make rubber harder and more durable. However, another Wikipedia page says that plasticizers play a significant role in rubber ...
4
votes
2answers
66 views

What grade of titanium are “memory titanium” glasses made of?

I've worked with different grades of titanium. Mostly with grade 5, and also grade 1 which is ductile. I know that some glasses are made of titanium and are called "memory titanium", I guess because ...
0
votes
1answer
58 views

Approach to solve a frictional problem?

I am having a bar and surface (made of aluminum). I need to attach some material to the end of the bar so that, if I apply any force (25 N-sideways) to bar it has to stick with the surface. Force ...
2
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0answers
19 views

What are the raw materials for water filter housing production? [closed]

I want produce water filter housing (like below images) who can tell me what are need raw material for these? Best Regards
2
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1answer
26 views

Mineral Hardness Scales

I am doing research into lunar regolith's hardness in relation to abrasion of lunar tools and need to choose a hardness scale (either Mohs, or Rockwell A, B, or C). Is either of these metrics more ...
4
votes
1answer
39 views

How to calculate strength for titanium wire

I'd like to use a titanium wire to make some jewelry. I ordered two kinds of titanium wire, 0.3mm thick and 0.5mm thick. Both of them are grade 1 titanium. How do I calculate the strength they'll ...
1
vote
0answers
33 views

Polyurethane with microbial resistance properties

I'm looking for a polyurethane with microbial resistance. Doing some research I found two commercial types: DESMOPAN 9392A and DESMOPAN 2792A. Both are manufactured under GMP conditions and limited ...
0
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0answers
28 views

What is the difference between PET bottles and PP Bottles?

Good morning. I'm currently researching the differences between PET bottles and Polypropylene bottles for my industrial engineering thesis. I'm currently designing a business model for a company that ...
1
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0answers
33 views

Does containing explosives in a metal cassing make a bomb stronger or weaker? [closed]

Does it allow pressure to build up until it ruptures like a pressure cooker with a blocked safety valve? Or does it absorb some of the energy in order to deform the metal? Or is it's net effect ...
2
votes
2answers
65 views

Viscoelasticity and Hyperelastic model, history and difference

Actually, I see some papers use viscoelasticity or hyperelastic model for the same materials. It seems to me that those models were invented in different eras, and the hyperelastic is a newer model ...
0
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0answers
19 views

Two wire tandem gas metal arc welidng (GMAW-TW)

Please explain how two wire tandem gas metal arc welding (GMAW-TW) process requires less heat input. Appreciated if reference is given.
1
vote
1answer
161 views

What is the straightest, longest and strongest pole that could be launched into space?

Which of these poles would be straighter and stronger then the others? These are some poles that are compacted making them possible to send to space. Sending a single solid pole .5km long will not be ...
1
vote
2answers
42 views

Max torque allowed on cypress wooden beam

I am trying to calculate the maximum torque that a piece of cypress wooden beam can handle before it snaps or becomes structurally unsound. I know this will depend on the thickness and width of the ...
1
vote
1answer
33 views

What type of plastic is a good clear, flexible plastic for prototyping? (~0.5mm - 1.5mm thick)

I'm prototyping a hardware that involves many thin walls to bend around curves and such, so it needs to be flexible, cheap, and also transparent. It may also be the same plastic used in a production ...
0
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0answers
38 views

Material strength and toughness to be bulletproof

Good day, I would like to ask you this question: Lets have a bullet with mass m = 0.2 kg and speed v = 700 m/s. The tip of this bullet is a circle with S = 1mm^2. Now this bullets hits target which is ...
0
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0answers
80 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 ...
3
votes
1answer
52 views

How to calculate the bending resistance of a square metal bar?

I have an old bend/twisted wooden door. It has some character to it so I want to keep it and add square metal bars to straighten it. I have provided a sample drawing of the door and where it is ...
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0answers
22 views

Timber selection for water-based applications

I am in the process of a design project for university. It is a floating mechanical pump that uses a frame fixed to 200-litre drums, similar to a barrel raft. One of the design requirements is a 10 ...
0
votes
1answer
23 views

The resistance of the given angle

Be it a resistive wire placed in a circular array forming a closed circuit, as shown in the figure on the side. With an ohmmeter, the resistance is measured between a probe attached to the 0 ° angle ...
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1answer
44 views
0
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0answers
23 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
58 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
votes
2answers
78 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
votes
1answer
72 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
vote
2answers
32 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
45 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
15 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
votes
3answers
104 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
73 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
votes
3answers
832 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
vote
1answer
69 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
29 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
votes
1answer
49 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
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 ...
0
votes
1answer
66 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
votes
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
vote
3answers
197 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 ...
1
vote
1answer
26 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
25 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
votes
2answers
38 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
votes
1answer
56 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?