Fig. 7
Exemplary nominal stress–strain curve of a semi-crystalline thermoplastic material. A = proportional limit; B = yield point; C = neck stabilization; D = fracture. a Undeformed chains, b elongated amorphous region and start of void formation, c disentanglement of amorphous chains, alignment of crystalline region and enlargement of voids, d formation of fibers (after [6, 14])