Mechanical Characteristic Values of Plastics

The mechanical behavior of plastics, in other words the relationship between strain a and the resulting elongation e and the force f acting on a molding and the resulting deformation AL is best characterized by tensile testing. Unlike the flexural test, tensile testing can also be carried out with the softer plastics [8, 66], 

In terms of the characteristic values measured by mechanical testing, a broad distinction is made between 

The tests and test techniques for ascertaining the short-term behavior of MID materials and impact behavior are dealt with in more detail below, because they are particularly relevant for sizing and designing MID. 

In accordance with ISO 527-1 and -2, dog-bone-shaped test specimens (ISO 3167 multipurpose test specimens) are stretched at a constant rate specified in the test standard. 

The relevant characteristic values are shown again in diagrammatic form in Fig. 2.4. Fig. 2.5 shows typical strain/elongation diagrams for selected plastics by way of example. The reliability of the MID is determined by the mechanics of the polymer basic body, so materials characterized by strength (elongation strain) and ductility are eminently suitable (see curves (b) and (c). Fig. 2.4). 

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