How Much Shear Force Can PVC Withstand Without Fracturing?

AI Thread Summary
The discussion focuses on determining the maximum shear force PVC can withstand without fracturing. The shear modulus (G) is calculated as 481 N/mm², and the applied shear force is 100 N with a resisting area of 28 mm². To find the maximum shear stress, additional information about PVC's maximum tensile stress is needed, as the relationship between shear and tensile stress differs for plastics compared to metals. The Von Mises criterion is referenced to relate shear yield point to uniaxial yield point, but the parameter μ, which affects yield point under pressure, is not clearly defined or easily accessible. Understanding these relationships and parameters is crucial for accurately calculating the shear force PVC can endure.
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Material: PVC
E-modulus: 1300 N/mm^2
Poisson's ratio: 0.35
Applied shear force: 100 N
Resisting area: 28 mm^2

Shear modulus: E = 2G(1+v) --> G = E/(2(1+v)) = 1300/(2(1+0.35) = 481 N/mm^2

Does this mean that a force which can be applied to the area without fracturing is 481 N/mm^2 * 28 mm^2?

I just need to know. How can I use this information to calculate how much shear force the area can be exposed to?
 
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G is the ratio of shear stress to shear strain, analogous to E being the ratio of tensile stress to tensile strain.

In order to answer your question about maximum shear stress of PVC, you will have to find out more information about the material (e.g., max. tensile stress) The max. shear stress is usually expressed as a factor * ult. tensile stress for ductile materials like metals. For plastics like PVC, there may be a different relationship.
 
SteamKing said:
G is the ratio of shear stress to shear strain, analogous to E being the ratio of tensile stress to tensile strain.

In order to answer your question about maximum shear stress of PVC, you will have to find out more information about the material (e.g., max. tensile stress) The max. shear stress is usually expressed as a factor * ult. tensile stress for ductile materials like metals. For plastics like PVC, there may be a different relationship.

I have an equation for polymers which describes the relationship between the shear yield point and uniaxial yield point based on the Von Mises criterion:

τy = ( ((1+μ)/sqrt(3)) /sqrt(3) ) * σy

From a diagram plotted by a stress test, I have the value for uniaxial yield point σy; the point where the material becomes subject to plastic deformation.

μ is a material parameter which determines the change in yield point with respect to a change in pressure. But I'm not sure how I can acquire this parameter, nor can I find any tables for this parameter. Neither do I know the name of this parameter. Is it effective viscosity?
 
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