Yield strength of polymers

Apart from that, the smaller the particle size, the stronger the structure formed by filler in the melt (that is, the yield strength of polymer ry is affected). Table 5 below demonstrates how the yield strength of molten polycarbonate composites depends on the size of CaC03 particles. 

Polycrystalline-Alumina-Reinforced Aluminum Alloy Compressive Yield Strength of Polymers Flextural Strength... 

In contrast to metals, the yield strength of polymers is different in compression and tension. Frequently, the yield strength in uniaxial compression is 20% to 30% larger than in uniaxial tension (see also section 8.4). To account for this, the von Mises yield criterion is augmented by terms that depend on the hydrostatic stress state. We will discuss two possible approaches. 

The yield strength of polymers generally depends on hydrostatic stress because hydrostatic compression decreases the specific volume and thus hampers shding of the molecules. This was already discussed phenomenologically in section 3.3.3. However, the criteria discussed there did not take crazing into account. 

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