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This topic is inspired by an interesting idea given to the forum by PhotonBytes, in early 2025.
The idea itself has to do with air pressure at various elevations on Mars.
However, as the idea is explored by NewMars readers, it will become apparent that compression pressure due to gravity increases more rapidly in the crustal material of Mars than is the case for the atmosphere.
The result of this difference in rate of growth of compression forces is that it becomes clear that a structure intended to survive at great depth on Mars, while open to the atmosphere as proposed in the scenario offered by PhotonBytes, must provide support service greater than has been achieved on Earth to date.
This topic is offered for NewMars members who might wish to contribute links or text to help NewMars readers to understand the physics of compression with depth in a gravitational field, and of various materials that might be considered to support a cavity under the surface where humans might reside.
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This post is intended to hold an index to posts that may be contributed by NewMars members over time.
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This post is a follow up to the interesting problem posed by PhotonBytes in his 55 Kilometer topic.
I asked Gemini (Google's extension of it's search tool) to "think" about materials in compression...
The all time winner is clearly diamond. If the pressure at 44 km on Mars is 4000 bar, then diamond will not be in the least phased.
On the other hand, Tungsten is apparently next in line for compressive strength, although in this round the numbers for Tungsten look low.
I may be asking for more than your resources can provide, and it so i apologize, but can you quantify the compressive strength of diamond in terms of bars. Thank you for suggesting tungsten as well. Is there information about it's ability to hold against compression on the order of 1000 bar?
You're right to push for specific numbers! It's important to have a quantitative understanding of these materials.
Diamond:
Compressive Strength: Diamond exhibits exceptional compressive strength. Theoretical calculations suggest it can withstand compressive stresses in the range of 469 - 470 GPa (gigapascals).
Conversion: 1 GPa = 10,000 bar
Therefore, diamond can theoretically withstand compressive stresses exceeding 4,690,000 bar.Important Note: These are theoretical values. Experimental measurements are more challenging due to the extreme pressures involved and the potential for experimental limitations.
Tungsten:
Compressive Strength: Tungsten is known for its high compressive strength. Typical values range from 1,500 to 2,500 MPa (megapascals).
Conversion: 1 MPa = 0.01 bar
Therefore, tungsten can typically withstand compressive stresses between 15 and 25 bar.
Key Takeaways:
Diamond: While incredibly strong in compression, its extreme brittleness limits its practical use in many engineering applications.
Tungsten: Offers a much more practical balance of strength and ductility for high-pressure applications.
Disclaimer: These values are general ranges. The actual compressive strength of any material can vary depending on factors such as purity, crystal structure, and the specific testing conditions.
I hope this provides a more quantitative understanding of the compressive strengths of diamond and tungsten!
What is the Strongest Metal in Compression? - Technische veren specialist | Tevema.com
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www.tevema.com
Material properties of diamond - Wikipedia
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en.wikipedia.org
Diamond is made by subjecting pure carbon to great pressure. Humans learned to make diamond some decades ago, but to the best of my knowledge (correction is welcome) human made diamonds are on the small side.
It would appear that if bricks could be made of diamond, then they should be able to easily handle 4000 bar at 44 km below the surface of Mars.
That is a ** big ** if.
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Since the figures found by Gemini in the post above (#3) seemed low, I asked Gemini to take another look.
Thank you for this additional insight! The citations you found for tungsten seem low. Titanium is known to be able to withstand 1000 bar when used to protect humans in an undersea vessel. Can tungsten perform as well or better?
You're right to question the previous compressive strength values for tungsten! I seem to have provided incorrect information.
Tungsten, in its pure form, can indeed withstand significantly higher pressures than the range I previously gave.
Tungsten Compressive Strength:
Tungsten can withstand compressive stresses well beyond 1000 bar.
Reliable sources indicate that tungsten can withstand compressive stresses in the range of several gigapascals (GPa).
This translates to several thousand bar, making it a highly suitable material for high-pressure applications.Comparison to Titanium:
While both tungsten and titanium are strong materials, they have different strengths and weaknesses:
Tungsten:
Pros: Extremely high compressive strength, high density.
Cons: Brittle, difficult to work with.Titanium:
Pros: Excellent strength-to-weight ratio, good corrosion resistance, good ductility (less prone to brittle failure).
Cons: Generally lower compressive strength than tungsten.
For applications like deep-sea submersibles:
Titanium alloys: Are often preferred due to their excellent combination of strength, ductility, and corrosion resistance.
Tungsten: Might be considered for specific components where extreme compressive strength is paramount, but its brittleness would need to be carefully addressed in the overall design.I apologize for the previous error in tungsten's compressive strength. I am still under development and learning to access and process information more accurately.
I hope this corrected information is more helpful!
Disclaimer: This information is for general knowledge and should not be considered definitive engineering advice.
Let me know if you have any other questions or would like to explore specific applications further.
Titanium vs Tungsten Rings: Which Is Right for You? - Rustic and Main
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All About Tungsten Metal - Xometry
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Titanium Properties - Kyocera SGS Europe
Source iconkyocera-sgstool.co.uk
This revised report implies that Tungsten might be able to handle the compression load at 44 km on Mars, but more research is needed to be sure.
A merger of diamond and tungsten (or titanium) might deliver a capability to support a chamber in living rock at 44 km on Mars.
What I'm thinking about is diamond bricks and metal mortar.
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A thick material of low stress capability supports the same force as a thin material of high stress capability, all else being equal. But, mechanical instability is the more important factor, by far, compared to material compressive stress capability, in vessels subjected to external pressure. I rather doubt your AI has any understanding of that, because most people do not.
Actually, I doubt any AI has any "understanding" of anything, because AI is just high speed computation coupled with trained imitation. There is no intelligence there, only imitation. "Artificial intelligence" is actually an oxymoron.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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