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quicksilver123
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Hi, I'm afraid I not very good at these questions just yet and would like a walk through a bit better than the one I was given by my tutors.
Thank you, please refer to the inline image.
The bulk modulus would allow you to calculate the amount volume strain, resulting from a given change in pressure ( ΔP ). The volume strain is dimensionless - think of it like a percentage change. If you draw a stress strain curve, think of the modulus as the slope of the curve in the linear region, and the Compressive strength as the point on the curve where it starts to fail.quicksilver123 said:The tutor wrote that out
I think the compressive strength is the inverse of the bulk modulus?
Could someone walk me through the problem solution? A few steps are skipped and the reasoning is not explicitly stated.
Good point. I should have stated that to let the OP know that those are not needed to solve the problem. The Compressive Strength is the maximum pressure that it is designed withstand before you are getting into risk of failure.Chestermiller said:Neither the bulk modulus nor the shear modulus nor the Young's (tensile) modulus determine the failure behavior of a material. The failure behavior of a material is not the same thing as its stress-strain behavior. They are entirely different concepts.
Actually, it is not the pressure (which is the isotropic part of the stress tensor) that causes failure. It is the anisotropic part (i.e., unequal principal stresses) that causes failure (along shear planes at an angle to the principal stresses). When we talk about compressive strength, we are talking about unixial loading of a bar or column, with zero principle stresses in the transverse directions. If we somehow placed the bar or column under isotropic pressure loading (like lowering it to the bottom of the ocean or placing it in a liquid high compressive chamber), it would not fail until a much higher compressive stress than the uniaxial compressive strength.scottdave said:Good point. I should have stated that to let the OP know that those are not needed to solve the problem. The Compressive Strength is the maximum pressure that it is designed withstand before you are getting into risk of failure.
Once I learned dyadic notation, all my problems with tensors vanished.scottdave said:Thanks @Chestermiller . Yes it is starting to come back to me. It has been around 20 years, since I took that materials course. But I do remember when I first was introduced to tensors. I had a similar feeling to the first time that I was introduced to imaginary numbers.
The inverse bulk modulus, also known as the compressibility, is a measure of how much a substance or material can be compressed under a given amount of pressure. It is the reciprocal of the bulk modulus, which measures the resistance of a material to compression.
The inverse bulk modulus is calculated by dividing the change in volume of a material by the change in pressure applied to the material. It is typically measured in units of pressure per unit of volume, such as pascals per cubic meter (Pa/m3).
The inverse bulk modulus is directly related to a material's compressibility. A material with a high inverse bulk modulus is more easily compressed and therefore more compressible. This can affect the material's elasticity, stiffness, and overall mechanical properties.
The inverse bulk modulus measures a material's resistance to compression, while the shear modulus measures its resistance to shear or twisting forces. Both are measures of a material's elasticity, but they represent different types of deformation.
The inverse bulk modulus can be measured using specialized equipment, such as a compression tester or a bulk modulus tester. These instruments apply pressure to a material and measure the resulting change in volume, allowing for the calculation of the inverse bulk modulus.