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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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What are the design principles for risers in sand casting?

Risers are added reservoirs used to feed liquid metal to solidifying casting. In the case of alloys that shrink during solidification (this is not the case of all alloys), one uses such reservoirs to ...
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2answers
24 views

Is a 1/8" AR400F steel plate strong enough, for 4,000 lbs?

I have a Ford F350 cab & chassis and a gooseneck trailer. For the gooseneck hitch I want to use a steel plate. The steel plate will be BOLTED to the frame, above the rear axle And the gooseneck ...
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0answers
23 views

Relation between burgers vector, slip plane, dislocation motion direction and dislocation line

I am really confused about the relation of this 4 entities. I know that the dislocation line is perpendicular to the burgers vector in an edge dislocation and parallel to the b vector in a screw ...
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1answer
76 views

How will using desert sand instead of concrete sand affect my concrete recipe?

I've read that desert sand is too round for concrete mixes. But, I'm not building a dam, I'm building a 3 foot landscaping wall. I'm interested in using desert sand for the color, so this is an ...
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1answer
20 views

Compressional Strain Definition

Strain in the x and y directions are defined by the following equations: $ε_x=\frac{du}{dx}+\frac{1}{2}[(\frac{du}{dx})^2 + (\frac{du}{dy})^2]$ $ε_y=\frac{dv}{dx}+\frac{1}{2}[(\frac{dv}{dx})^2 + (\...
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1answer
32 views

Help with determining the dimension change in the xyz direction of a component under a load?

I'm stuck on this question. I got the first part right which is to work out the dimension change in the x direction but I got the y and z directions wrong. I had to submit this online and it doesn't ...
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14 views

Phase prediction by cct diagram

Can someone please help in finding out the phase proportion of each phase w.r.t time , cooling rate and temperature by using (mathematical model to predict phases from given cct diagram) Leblond ...
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15 views

What's the methodology for adequate tetrahedralisation?

I'm running a linear elastic solver generating the tetrahedron's using tetGen. It's not clear to me though how one defines what's an acceptable tetra density that provides sufficient accuracy. You ...
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1answer
74 views

Which way of joining is stronger?

I have to build a box to extend the length of a projector bracket: The projector bracket weighs 7kg and has an arm of about 500mm. The projector weighs another 5kg. The box has a depth of 140mm. ...
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0answers
17 views

Ion exchange membrane that is dimensionally stable in organic solvents

For an electrochemical flow cell stack employed in electrosynthesis, I require an proton exchange membrane (PEM) in order to enable "divided cell" electrolysis mode. The Nafion proton exchange ...
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2answers
58 views

Could pre-stressed graphene be used to reinforce granite block construction?

I am curious whether this will become an option, especially for longer lasting structures. Could pre-stressed graphene or another high tensile strength material by used to reinforce granite block ...
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1answer
37 views

Stress strain curve [duplicate]

According to uniaxial stress strain curve, specimen fails at a certain stress value since necking begins. My question is that, same stress value appears before necking especially around yield point ...
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27 views

Is acrylic OK for children's toys under EU regulations?

I am developing a toy for 2-6-year old children with parts in acrylic ( Poly(methyl methacrylate)). I searched Toy Safety Directive 2009/48/EC and Regulation 1907/2006 REACH for mentions of perspex or ...
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17 views

How to find phase proportion at equilibrium - from iron-carbon diagram - Leblond

{Equilibrium proportion P, this is the proportion which is reached at a constant temperature after an infinitely long time:P is also the austenite proportion in the case of extremely slow heating. It ...
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3answers
96 views

Strength vs. Hardness vs. Toughness

for this question: "What is the difference between strength, hardness and toughness in materials?" i have searched and have found these following definitions Strength refers to resistance to ...
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1answer
34 views

Screw Dislocation and Edge dislocation

If in both cases if there is an application of Shear Stress then why do we have Screw dislocation in one case and Edge dislocation on the other?
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1answer
25 views

Which material index should be maximized for a component in a Car's manual type HVAC?

I was doing a case study on the plastic used in cars for controlling the AC in a manual type system which actually snapped in mine it just rotates according to the knob position in the dashboard, ...
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1answer
14 views

Finding Stress Concentration Factor when (D/d) ratio is not on a table?

So we have this homework problem, it is a rectangular filleted bar and we have to find the minimum thickness. I go and calculated the ratios but here's the problem: (D/d) = 1.375. What may the problem ...
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10 views

What bending test and torsion test standard are recommend for a surfboard?

I wish to find a bending and torsion test standard for a surfboard (non-prismatic) that is roughly 2000mm long. The closest I've found for bending test is probably those ones that are designed for ...
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0answers
17 views

How can I increase the strength of this clutch without shearing my bushings?

Here's the setup: (C) is a clutch. Beyond (C) is the source of torque. The belt (D) transfers the motion from the clutch to the sprocket (B). (B) then transfers the motion to (A) by way of 9 ...
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0answers
27 views

Why the Tensile modulus is always larger than Tensile strength?

I can't figure out this huge difference in values between these two mechanical material properties. When its refer to flexural strength and modulus there's a difference in value (if the material is ...
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2answers
47 views

Can a simple application of two forces have two different outcomes on a rigid body?

[Summary: If two forces are such that the component of one of these forces forms a couple with the other, than which of the two cases (obtaining resultant via adding forces or obtaining moment and a ...
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2answers
41 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
49 views

Why do people build the core of a sandwich structure using compsite

Usually I see composite as a laminate wrapped around the core of a sandwich structure. Usually in loading such as bending the bending stress is the highest furthest away from the neutral axis, while ...
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1answer
41 views

Force required to deform sheet metal

Hi all. I am building a machine to deform sheet metal into corrugations. I have attached an image that I got off a presentation from MIT's website. In the example, they provide a formula for the ...
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1answer
35 views

Which is more important XY plane thermal conductivity or z direction thermal conductivity?

Im seeking an alternative to thermal grease/ pastes. I was researching graphite pads when I stumbled across the soft PGS line from Panasonic. I need to choose a suitable thermal interface material ...
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2answers
38 views

Why does aluminum clad steel wire have high corrosion resistance?

Why do aluminum clad steel wires have high corrosion resistance despite being two dissimilar metals? Does the aluminum act as a protective & sacrificial layer similar to zinc in galvanization or ...
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1answer
41 views

Does tunnel lining made of cast iron tubings actually accept all the mechanical loads?

Here goes a recently opened underground railway station in Moscow, Russian Federation (image is from here) On the left is an undecorated (just painted and it will likely remain this way) tunnel wall. ...
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1answer
54 views

Recommendations on a rigid connection between materials

I am trying to construct a torsion pendulum/balance for a physics experiment but the research papers are always missing specifics on how the certain connections are made. I am looking for ...
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1answer
27 views

A problem on mechanics of materials

I would be appreciate if anyone can solve problems below for this beam. ・Find the all sectional forces $F_x,F_y,M_x,M_z$ for both elements① and element②. ・Find elastic strain energy of element① ...
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1answer
57 views

Torsional rigidity D vs torsional rigidity factor k vs torsion constant J

I have a physics background so apologize my ignorance. I'm confused by the constants $D$, $\kappa$, and $J$ when it comes to torsion of beams. From what I understand $\kappa$ and $J$ are the same ...
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1answer
34 views

How to perform 3 point bending test by using force instead of displacement in ABAQUS?

I know you can apply displacement to a rigid body (cylindrical rod) to perform a 3 point bending test in ABAQUS. Is it possible to apply force to the rod (e.g. rod with super high young's modulus so ...
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2answers
37 views

Stiff rod / tube - What material and diameter

I need a long arm which will transmit motion from a motor to a pen. It needs to be about 500mm long. What I want to try and do is reduce the bend (i.e make it stiff) but also make it fairly light. ...
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1answer
42 views

what actually cause quench cracking ? non-uniform cooling or rapid cooling?

It’s well known that quenching most alloyed steels starting from AISI 4140 to high speed steels in water, brine , or sometimes oil will cause cracking and distortions. in industry oil quenching ...
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1answer
76 views

What is the strongest and lightest material?

I have heard titanium is the strongest and the lightest material. It is used for my glasses frame. Is it true that it is the strongest and the lightest as well? Strongest, the biggest forces can it ...
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3answers
340 views

How to push an endoscopic camera upto 20 meters in a horizontal pipe?

I have a small endoscopic camera (custom made). I wanted to push the camera inside a horizontal pipe of dimensions varying from (25 mm to 65 mm ID). But the wire attached to the camera is not stiff ...
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Can high alloy tool steels be quenched in brine?

It is will known that most of tool steels are quenched in oil to prevent cracking and distortion which appears when quenching in water due to non-uniform cooling caused by formation of insulating ...
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0answers
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Looking for something to reflect ultraviolet light at extremely low wavelengths

I have been working on a product that involves the reflection of low wavelengths of UV light (200-250nm). However, I have not come across many materials that are able to do so and the high-...
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2answers
57 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 ...
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1answer
48 views

Is there is vanadium-free high speed steels?

Vanadium is present in all high speed steel grades. unfortunately vanadium not only very expensive but is also a will known cytotoxic metal. some workers get severe persistent cough lasts for months ...
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1answer
29 views

Generic category of PBT thermoplastic

I'm an EE, but I'm working on a project at work where I need to venture into materials science & chemistry. My question is, does thermoplastic, Polybutylene terephthalate (PBT), fall into any of ...
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2answers
61 views

which type of casting will give higher cooling rate, casting in thin water-cooled copper mold or casting in thick copper die?

It is will known that increasing cooling of a metal casting will lead to finer micro-structure which mean higher mechanical properties. If I have 2 molds one is thick copper die ,& second is just ...
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1answer
56 views

derivation of Young's modulus experiment formula

In an experiment used to find the Young's modulus of a steel bar, the formula for change in height is given as follows: $$\delta_x=\frac{Fx^2}{6EI}(3L-x)$$ $$I=\frac{bh^3}{12}$$ where: $δ$- the ...
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0answers
34 views

Does speed matter while one steel part is pressed into another?

If one press some steel part into steel hole to get unsplittable assembly, does this operation speed matter? Is it better to hit by hammer, or to slowly jam with vice? Does it relate to steel type (e....
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0answers
19 views

Dense, non-conductive UHV compatible material?

I'm not sure if this sort of question is appropriate here or not so please let me know if not! I am designing a UHV vacuum system with a few interesting requirements. Inside of the vacuum chamber ...
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1answer
115 views

What is the difference between work hardening and strain hardening?

I have come across the definition somewhere,"Work hardening, also known as strain hardening, is the strengthening of a metal or polymer by plastic deformation. This strengthening occurs because of ...
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1answer
60 views

Material with strongest grip on Aluminium 6061

Attached is an example picture of a clamp that will be attached to a pipe made of Aluminium 6061-T4. The clamp should have very tight grip on the pipe and prevent it from slipping or rotating but the ...
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1answer
84 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?
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1answer
50 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. ...
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0answers
39 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 ...