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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Low temperature flexible polymers

I'm working on a design project that will require a flexible component that will be operating at temperatures from $0^{\circ}$C to $-200^{\circ}$C. Are there any thermoplastic polymers that remain ...
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How to calculate Average temperature from area under the curve?

Let us say I have a graph of temperature against time for a material as shown here. I want to calculate the average temperature. Will it be simple mean of the curve or rms of the curve? Edit: The ...
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Calculating young's modulus of a metal from compressive stress and strain curve?

I know that young's modulus is rise over run of the curve in the elastic zone. But what do you do if the the curve is for a ductile material under compressive load, which has no clear yield point or ...
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1answer
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Initial shallow gradient in measured stress strain curve

What's causing the initial shallow gradient of the stress strain curve of ceramic in this graph? The rest of the curve is a straight line alright until the yield point. Edit: the material being tested ...
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1answer
48 views

How to know the material of key-top?

There are keys (push buttons) on the front panel of an avionics device that fits inside the aircraft cockpit. I need to know the material of which those key-tops are made from. I can guess the ...
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is there a hard castable ceramic i could use to make an engine cyllinder?

Im thinking of building a model piston engine. Since i don't have machining equipment i will need to cast it out of something. Melting metal requires some equipment (i tried melting aluminium in a ...
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2answers
56 views

Does a change in specimen dimension affect the measured yield strength and tensile strength?

I am having a hard time trying to understand the effect of geometry on a specimen's yield and tensile strength or if there even is one. If there is an effect or not, why is it so? Thanks in advanced!
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Durometer and Shore

Can someone help me understand durometer and shore hardness testing with relation to rubber hardness? My understanding is durometer measures hardness, shore is a different type of scale. The image ...
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1answer
18 views

How many kind of material resistance are there in engineering?

I have seen many kind of material resistance mentioned scattering around, such as fracture resistance / deformation resistance / chemical resistance / weathering resistance and so on But I cannot find ...
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1answer
24 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 ...
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1answer
22 views

Is there a material that returns to original, curled form when straightened?

Is there a material that 'wants' to be curled up but can be straightened an indefinite number of times without failing?
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1answer
29 views

Is it just surface area alone that causes bridges to freeze?

Scenario: Object 1, a bridge freezes over do to the surface area exposed to the below freezing air. Object 2 has the same surface area exposed to the same air, but its base sits on the ground that is ...
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2answers
26 views

How to choose the right liquid pump?

I'm an electrical engineer building a pump system to transport various disinfectants from large drums into smaller bottles for my parents' family gym business. I've realized that I need something ...
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Is it possible to get the hardening exponent and coefficient (n, k) if I just know the yield point, the ultimate stress, and the failure strain?

For a certain steel I have the following data: Yield stress and strain (engineering) Ultimate tensile strength (engineering), I don't have the strain at this point Strain at failure (engineering), I ...
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3answers
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Better / Cheaper Material Choice?

Current State Currently I have designed a coffee roaster that mostly uses the stainless steel tri clamps / tubes that many brewers use. The system can get up to 450 degrees F (232°C) even with moving ...
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3answers
28 views

Material selection of heating element

I am interested in heating coils which are heated using Ohmic/Joule/resistive heating - specifically, how the material for the heating coil is selected. When I read about heating coil materials - ...
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1answer
30 views

How can i clearcoat galvanized steel?

My immediate thought was Rust-Oleum clear spray, but rustoleum, krylon, and any other alkyd-based paint will react with the zinc and flake off. Primers cover the patina and are therefore not useful. I ...
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1answer
40 views

Purpose of a GD-Zn alloy

Here are screenshots of the data-sheets of two separate products for a reference. They both are nickel plated, used for coupling nuts. The former is shielded, the latter is not, I wonder if this is ...
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1answer
43 views

Pullout Force of Screw from Epoxy

I would like to estimate the pullout force required to pull a screw out of epoxy. Mine is an unusual situation where I want the joint to fail to protect other parts of the assembly; that is, it is a ...
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1answer
26 views

Galvanic compatibility with mild steel

Let me just get this out of the way: this is a total newbie question. But I appreciate any advice I can get! I'm rebuilding / retrofitting a wood-and-steel trailer, and trying to identify affordable ...
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1answer
41 views

How did OXO get text into this inside feature?

I am a student trying to learn about how OXO made this cup. Here are some constraints that I know: I figured out that the text on the outside can be made using screen printing, but then I don't think ...
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1answer
28 views

What's the thermal bounds of a typical computer case fan?

I'm thinking of repurposing computer fans (case fans and/or CPU/GPU fans) for a hobby steam turbine project. So the idea would be to use the fan rotors in the turbine to drive the shaft (discarding ...
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0answers
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Estimation of cutting torque for circular saw device

How could I estimate the required torque for cutting through wood using a blade, say 180 mm in diameter? I am not too sure how to approach this.
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1answer
41 views

sinking speed of particle in water

For a Newtonian fluid the sinking final speed of a metal particle is given by this equation : while g is Gravitational acceleration , $\rho_P$ = is particle density , $\rho_F $ = is fluid density ,...
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Determining the heat capacity of an X-Band transmitter

I am conducting a thermal analysis of an X-Band transmitter that will form part of the payload in a CubeSat. The goal is to determine how long the X-Band transmitter can operate before it will ...
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1answer
31 views

What is the relationship between the strain in different directions?

A cube made of an isotropic material is subjected to a tensile stress as shown in Figure 2. What is the relationship between the strain in different directions ? There is an elongation in $z$ ...
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1answer
20 views

Constant crosshead speed or constant strain rate for comparing samples of differing thickness?

Say I have two different specimens of a material, one is 10mm thick and the other is 1mm thick. Assume that this material has properties which vary depending on the rate of deformation (I would call ...
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Thermal expansion during the course of melting (in metals specifically)

The question is with regards to Thermal Expansion at the point of melting. My basic understanding is that a material will generally undergo linear thermal expansion until some phase change occurs (...
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19 views

Is it possible to use a laser push a 100 micron diameter droplet of water through a fine mesh?

Context I've had the thought of a printing device that uses a thin grid that has holes small enough to allow suspension of a water based ink above a sheet of paper using surface tension. I've ...
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0answers
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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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2answers
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What type of material is this?

I'm sorry if the question doesn't fit the site but I didn't know where to ask. I found this at a car service where the guys used this thing to correct the painting on the car on the regions where ...
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1answer
50 views

Non-toxic material for deformable wire/rod without work hardening

I am looking for a non-toxic material for a wire/rod that allows room temperature deformations without work hardening. Example uses are semi-rigid cables that one can bend and that hold their shape ...
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1answer
37 views

Why Does Particle Size Matter For Bridge Pillars here?

I was watching this engineering video here and it talks about a technique used to prevent the pillars of a bridge from falling over in an earthquake. The pillars of the bridge are partially submerged ...
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1answer
40 views

Safe temperature thresholds for #2 HDPE and #5 PP plastic

It would be convenient to use a temperature adjustable heat plate (element)/mug warmer for the massive amount of blender bottles accumulated over the years. What are safe thresholds to safely warm the ...
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2answers
44 views

Why do they vacuum pump the carbon fiber fabric?

I have seen plenty of YouTube videos in which they use carbon fiber fabric to build various things. One such channel is Mike's Patey's channel where he makes amazing aircrafts from carbon fiber. In ...
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1answer
26 views

Maximum bending stress and neutral axis

I need to calculate the maximum bending stress So let $r$ equal the radius $$\frac{1}{r} = \frac{M}{EI}$$ $$\sigma_{max} = \frac{Mc}{I}$$ $$\Rightarrow \sigma_{max} = E\frac{c}{p}$$ But how do I ...
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28 views

Galvanic corrosion in a non-corroding environment

If we submerge a welded structure of, for example, Duplex (1.4462) and Stainless Steel (1.4301) in water, which is normally not a threat for either of these materials alone, do we see corrosion in the ...
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2answers
42 views

Soapbox - GoKart material - Bamboo or steel?

I am building a soapbox (go kart) and I am planing on what materials I could use for the frame and the chassis. I have thought about using bamboo or steel. Steel is normally the go to material when ...
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2answers
17 views

Elongation values for materials

According to EN standards, elongation for each material type has been defined, and it varies with different range of thicknesses for the same material. Why is it so? How is this value calculated?
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1answer
27 views

Why don't car manufacturer's use a combination of disc brakes and electeomagnetic brakes to reduce braking distances?

It many be due to costs or that the brake discs would have to be made out of aluminium/copper for the electromagnetic braking to be effective or there may not be a significant reduction in braking ...
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0answers
28 views

Lagrangian of a piezoelectric material

I'm confused about the Lagrangian of a piezoelectric material. I've seen multiple sources which seem to contradict each other. The way I personally approach the problem is the following ($\underline{...
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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
31 views

Looking for thin flexible and strong material

I have a project in which I have to use a up to 2.5mm diameter needle with a 90 degree (L shape) angle similar than the one in the following picture: I say similar because there is only the tip of ...
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0answers
36 views

Aerogel to filter virus particles

With the hype around COVID-19 DIY technology, everyone seems to circle around the same concepts. I'm trying to think outside the box and I was wondering: Is it possible to controllably create an ...
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How is EPD different / related to anodising?

What is the process of applying dye to anodized surfaces (specifically aluminum)? Is electrophoretic deposition (EPD) just the process used to apply the dye to anodised surfaces? Or is it a ...
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1answer
51 views

Why does fatigue crack growth require unloading?

When a crack has been initiated in a material, further loading of the material causes stress concentrations at the crack tip. This high stress causes the material to break at the tip and the crack ...
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1answer
29 views

What material can withstand continuous working temperature of 1000 degree Celsius?

I'm designing a block for creating turbulence inside a traditional furnace. I would like to know about a material which is economical and can be put into operation for more than 2 years.
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1answer
47 views

What is the less ductile and thinnest wire material?

I'm looking for a very very thin wire that does not bend easily. Which kind of material should I look for? The thinnest the wire the better but copper can be found in a very thin format (0.01mm) but ...
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Considerations for switching from Conc. Sulphuric acid to Oleum

First off - this project is still in the early planning stages. The basic scope is that a plant want's to switch from using conc. sulphuric acid (~98%) in its process (nitration) to oleum. I ...
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279 views

Is surgical and medical mask based on static electricity?

Is surgical and medical mask based on static electricity? By static electricity I mean like 3M N95 mask with at least two different layers of positive and negative static electrical layer. I googled ...

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