Shear Modulus, Modulus of rigidity

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Discussion Overview

The discussion revolves around determining the shear modulus (modulus of rigidity) for a bar of unknown material based on experimental results from a torsion experiment. Participants seek to analyze their findings, identify the material corresponding to their calculated G value, and discuss the credibility of available reference tables.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant shares their experimental result of 86.7 GPa for the modulus of rigidity and seeks guidance on analysis and material identification.
  • Another participant questions the accuracy of the G calculation and whether the material is metal.
  • The original poster confirms the calculation was supervised and identifies inconel as a close match at 79-80 GPa.
  • A participant finds a credible table of shear modulus values, noting that steel and nickel are close at 83.9 GPa, but still not matching the 86.7 GPa result.
  • There is mention of stainless steel as a potential close match, but no definitive conclusion is reached.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the exact material corresponding to the calculated G value, with multiple materials proposed but no consensus on the best match. The discussion remains unresolved regarding the identification of the material.

Contextual Notes

The discussion highlights the limitations of available reference tables and the potential discrepancies in reported shear modulus values for different materials.

gbenga
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Hello lol first post . so I've done an experiment in determining the modulus of rigidity for a bar of an unknown material (torsion experiment). I have been asked to analyse the results, which I still have no idea what that means and find the material with the G value that i have. I've been searching Google and the only material material close enough to my value is about 6.5 GPa off and the tables are usually a small selection of common materials.
So is there any table available where i can find out the material used in the experiment and can someone explain what i need to do in the analysis since I've described the results in the data section with the table and graphs and calculations.

Thank you
 
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gbenga said:
Hello lol first post . so I've done an experiment in determining the modulus of rigidity for a bar of an unknown material (torsion experiment). I have been asked to analyse the results, which I still have no idea what that means and find the material with the G value that i have. I've been searching Google and the only material material close enough to my value is about 6.5 GPa off and the tables are usually a small selection of common materials.
So is there any table available where i can find out the material used in the experiment and can someone explain what i need to do in the analysis since I've described the results in the data section with the table and graphs and calculations.

Thank you
What's the absolute value of G for your material?

Chet
 
86.7 GPa ...i do need the source, if you happen to find it. It'd be better if you could refer me so i can feel like i did the work lol
 
Are you sure that you calculated G correctly? Are you sure it's metal?

Chet
 
Chestermiller said:
Are you sure that you calculated G correctly? Are you sure it's metal?

Chet
yes i calculated it correctly, with supervision from the lab supervisor. The bar used was indeed metal. the closest to the value I've found is inconel at 79-80 Gpa
 
could not edit my previous reply.
I found a table with some values of shear modulus and it looks like it is credible but the closest are two materials, steel and nickel. both 83.9 still some way off 86.7. the table is here: http://www.kayelaby.npl.co.uk/general_physics/2_2/2_2_2.html
I'm just looking to get to the closest i can (best advice i received from supervisor lol)
 
gbenga said:
could not edit my previous reply.
I found a table with some values of shear modulus and it looks like it is credible but the closest are two materials, steel and nickel. both 83.9 still some way off 86.7. the table is here: http://www.kayelaby.npl.co.uk/general_physics/2_2/2_2_2.html
I'm just looking to get to the closest i can (best advice i received from supervisor lol)
Stainless looks close enough.

Chet
 

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