# 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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### Best material to prevent stainless steel wire abrasion (polyamide coated)

I have a 1.5mm diameter wire that must be pulled against the corner of a surface. The wire is made of stainless steel and coated with polyamide. What is the ideal material to make corner of the ...
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### What happens to insulation?

What exactly happens when an insulating material comes in contact with heat through any mode (conduction, convection, or radiation). Something like aluminized mylar will reflect the heat back. How ...
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### Spinning disc stress distribution

For a thin spinning disc, is the boundary condition on the outer surface that the radial stress is zero? If so, how is this consistent with the fact that the outer surface of the disc has a ...
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### Is half of depletion region a part of N region or P region?

Is it correct to say that if the P-N junction is in the middle of the depletion region, half of the depletion region is for the P region and the other half is for the N region?
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### Resources for engineering with wood

I'm an engineering student and I've just taken my first solid mechanics course and I absolutely loved it! However, most of the problems in the textbook tend to deal with materials like steel, copper, ...
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### Suitable ranges of electrical conductivity considered for semiconductors

I'm working on a Materials Science project guided by Machine Learning, where I try to predict the physical properties (in particular electronic properties) of materials given stoichiometry. As I'm ...
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### What would happen if we applied a stress greater than the yield stress to a rigid-perfectly plastic material?

Say we had a material that was rigid perfectly plastic, with a stress-strain characteristic as shown: Say that we are drawing this material through two dies, something like this: What would happen ...
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### orthotropic elastic moduli for laminated plates versus parallel rods

I am very confused about the directions of shear stresses in orthotropic materials, with two examples in particular. In a stack of laminated metal plates for example (the z-direction taken to be ...
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### Size characterization

Which technique can I use to characterize the size of my particles? They would be in the range of 50 μm to 300 μm. I have verified using a microscope, but I need a technique to analyse the size ...
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### What is the significance of brittle materials and why do we use them?

What is the significance of brittle materials and why do we use them? As you can see in the stress-strain curve, brittle materials have extremely low plasticity, in which cracks can initiate without ...
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### Alternatives to zinc die cast (Zamak)

I am working for a small domestic home appliance manufacturer and we are looking at ways to reduce our appliance's carbon footprint. Currently we use a lot of die-casted zinc-aluminum alloy (Zamak, ...
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### Requirement : Open Source API providing properties of engineering materials [closed]

We are a bunch of four in the ultimate year of the 'Bachelor of Engineering - Mechanical' degree. Our final year project is titled 'Computer-Aided Part-Code Generator for industrial parts'. For the ...
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### What Materials and Load cells are suitable for a Medical Weighing device?

I'm creating a medical weighing scale for immobile patients for my final year project in college. The weighing scale is a flat surface that can be slid underneath the patient. I'm at a standpoint as ...
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### POM-c/POM-c (dynamic) coefficient of friction

I've googled around but can't seem to find the value for the coefficient of friction (dynamic preferably) of POM-C sliding with POM-C. Does anyone have information on this?
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### Measuring delamination area in imageJ

I am measuring the areas of delamination in glass fibre reinforced composites using imageJ. I converted each image into an 8-bit grayscale image and then used thresh holding to show the delaminations (...
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### What is the difference between Hooke's Law and Young's Modulus?

In the elastic region where stress is proportional to strain up to elastic limit which is we call Young's Modulus (E). My question is if that is E, then what is Hooke's Law (K=F/x spring stiffness). I ...
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### How to measure compression modulus of a paper-thin elastic sheet

Is there anyway to measure the young's modulus with a compressive force on a paper thin elastic sheet (made out of a rubbery-fabric material)? I wish to compress the sheet in an orientation that ...
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### Effect of adhesive on ballistic fabrics

Adhesive is applied to "soft" ballistic fabrics (like kevlar or even fiberglass) in order to decrease bulge when being hit by a projectile. What would be the effect of gluing layers of ...
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### Why do rare-earth permanent magnets need to be recycled instead of just reused?

For years, scientists and engineers have struggled to find ways to efficiently break down and recycle rare-earth materials from various devices, especially permanent magnets.... My question is: Why do ...
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### Inverse Power Law for Accelerated Failure Times

I am working with some subsea cable data. I have $n$ samples that are split into three groups (sized $n_1$, $n_2$ and $n_3$). Each group goes through a different acceleration process until failure. ...
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### Best way to prepare a rusty metal surface for hardness testing?

I have a hardox #10mm plate that needs to be tested on Rockwell hardness. As hardox is sensible to heat I would like to avoid any heat treatment before the testing. The plate has been water cut. The ...
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### Up to what temperature, can titanium be safely used?

I was thinking about the realization of a pottery oven, and I wondered which material I could to make the inner walls. Most often the inner walls seem to be made of some kind of hard mineral wool. I ...
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### How could these 2 concrete pours affect algae build up?

Here's the image: https://ibb.co/12kJCg8 First off, I live in a third world country with little standards for home building. My family's driveway ended up like this as the laborers somehow didn't ...
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### What does it mean for a polymer to absorb water and how does this relate to hydrophobicity?

My materials teacher mentioned a polymer that is used for its hydrophobic properties but also can absorb water. How can a polymer do both of these things?
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### Plastic hardness after machining vs molding

Should there be any difference in the hardness of a plastic material that is machined vs one that is pressed from a mold? This question is in specific reference to vinyl record production where ...
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### Examples of Materials with a Coefficient of Kinetic Friction Very Close to or Equal to Coefficient of Static Friction?

I'm looking for examples of frictional materials that have a coefficient of kinetic friction that is as close to equal to their coefficient of static friction as possible. What is an example of that ...
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### Material selection for plunger to be compatible with pressure seal

I am designing a jig to insert a pressure seal into a cap. The jig has a cavity which the cap fits into and then is loaded with the pressure seal which needs to be inserted further using a plunger. I'...
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### Is it possible to calculate the strains applied by a force on a molecule? [closed]

This question was originally in the Physics site, but the moderator believed it was better suited for this site. Hence, I am following the advice. Is it feasible to obtain the modulus of elasticity ...
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### Why does Poisson's ratio always have the axial strain as the denominator?

Why can't we divide the lateral by the axial strain? Why does the axial strain always have to be the denominator? Would it matter if I was careless and accidently switched them around?
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### What aluminum grade is the most resistant to corrosion in alkaline environment?

Quick google search will return either 6000 series (6061 more specifically), or 3003 However with so many option and each having it's own benefit, I still haven't make my decision What I am looking ...
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### What wire rope to use for a load-bearing telescoping lift, and how to secure it

I'm trying to find a thread that has good fatigue resistance and strength for a telescoping lift to be used in a robotics competition. The lift will lift a weight of around 2-3 kg. I do not intend to ...
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### Influence of design on corrosion control

In "Ahmad. (2006). Principles of corrosion engineering and corrosion control (1st ed.). Elsevier/BH.", it is stated that to fight against metallic corrosion it is more convenient to design (...
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### Electric heating element inside refractory concrete

I'm thinking of making an electric pizza oven in my free time. My thinking at the moment is to have one kilowatt electric heating elements in the bottom as well as the top of pizza oven. I would like ...
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### How to integrate a heater in polyeurethane foam?

We are trying to integrate a heater in polyeurethane mattresses. However, the heating units we found are in fabric shape and hence the moment we pressurize the PE foam in the mold they deform and do ...
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### Vapor deposition of 5um Beryllium onto 0.5um mylar

I am searching for a service that allows the deposition of 5 micron thick Beryillium onto half micron thick mylar for a R&D project I am doing. I am having a difficult time finding such a service ...
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### Will the material plastically deform or fail when heating or cooling?

You have a stainless-steel rod with constraints on both ends that is held rigid. Initially, it is at room temperature before getting heated to 300 Celsius. Then, it is cooled to room temperature again....
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### mechanism design for matrix of adjustable direction pointer

I need to construct a matrix of light pointers, each one aims in specific direction, and each pointer direction will be adjusted thousands times, size is flexible could be millimeters or centimeter ...
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### Is there a cloth-fabric that hardens on impact?

I am researching if there is a cloth/fiber (that can be worn) that instantly hardens on impact? I am well aware of oobleck - but this is a liquid. I also know of D30, which is a material that hardens ...
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### On Which Side Will The Tyre Wear Out More?

Whilst watching a F1 race recently I noticed the commentators talk about how all the cars on that race day started observing more/faster wearing down of the tyres on the front left of the car relative ...
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### Failure load of hollow tube under transverse compression

How would one analytically calculate the maximum force a tube under transverse compression can withstand? I am specifically looking for a general equation to model the yield strength of a hollow tube ...
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### Is it possible to estimate the young's modulus of an aluminum alloy purely based off its alloy designation?

I recently had an interview where the interviewer asked what the young's modulus would be like for an alloy like 5052 versus 6061. was a bit stumped on this one, saying that 5052 might be lower ...
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### Is there a difference in cast vs extruded acrylic with regards to how they appear in x-rays

I'm working on the experimental apparatus of an extension of this paper: https://arxiv.org/ftp/arxiv/papers/2110/2110.09017.pdf We basically have to make a bucket using an acrylic tube. My question is,...
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### Magnetising a needle with static electricity using silk cloth

A nautical navigation textbook on my table says that we can magnetise a non-magnetised needle by rubbing it with a silk cloth. I decided to cross check on the internet, and found some experts calling ...
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### Brittle = highly stiff but not very strong

I was trying to imagine materials undergoing collisions, and thought about materials that do not deform at all. Naturally this is an idealization that does not exist in reality but, if it did, I ...
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### Do piezoelectric materials produce a current flow or just an electric field?

I was watching a video https://www.youtube.com/watch?v=uvT3XvDSSQw about piezoelectric materials. They mentioned that "a current can flow when a pressure is applied to the material". I have ...
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### where did the concrete splitting test calculated stress formulat come from?

In compression test of cylindrical concrete sample we get the normal stress easily by dividing failure force by sample cross section, but how we can explain the formulat used to determine tensile ...
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### Preventing leakage in sludge tank

I recently went on a tour to a local water company plant where we were shown a sludge tank which is where the sludge in the water is removed and stored here. The sludge can be acidic and so can cause ...
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### What rubber to use to grip stainless steel?

I need to secure a plastic bobbin on a 316SS shaft so it can be wound in a winding machine. There is a potential for undesirable axial and rotational drift that I need to prevent. My initial thought ...
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### Impact damage in composite materials

I want to do a test where I use composite materials to mimic impact damage on aircraft materials such as impact from hailstone while the aircraft is in flight. I will cut out specimen sheets using a ...
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### How long will it take to anneal at a lower temperature?

Someone is trying to anneal a brass casting to minimize the segregation of Zinc. He likes the results of annealing at 400 Celsius for 3 hours, but the high temperature produces problems with residual ...
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