PSI - Issue 13

Lesiuk G. et al. / Procedia Structural Integrity 13 (2018) 1595–1599 Author name / Structural Integrity Procedia 00 (2018) 000 – 000

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However, the J-integral approach will be the most useful in many engineering tasks. On the other hand, its implementation could be not simple in engineering practice.

Fig. 1. Typical PUR elastomers in vehicles parts

In a last decades, the Essential Work of Fracture (EWF) is a promising substitution and alternative in a polymer testing by several researchers; Mehmood et al. (2012), Gamez-Perez et al. (2009), Arkhireyeva, A., and S. Hashemi (2001) and ESIS (European Structural Integrity Society) recommendations: Clutton (2001) It should be underlined that, the physical explanation and relation with J-integral approach are well documented in work of Arkhireyeva, A., and S. Hashemi (2001). The main fundamentals of energy approach EWF for PUR elastomers (Lesiuk et al. (2016)) can be shortly represented by the W -specific total work of fracture referred to the non-fractured ligament L area (divided by the Lt, t-thickness of specimen): W We Wp    , (1) where We represents essential specific work of the fracture referred to the non-fractured ligament area (divided by Lt, t-thickness of specimen) and  Wp -non-essential – plastically dissipated energy work of fracture referred to the non-fractured ligament area (divided by the Lt, t-thickness of specimen).  -factor is a scalar, non-dimensional factor associated with geometric shape of deformation zone.

2. Fracture susceptibility and fatigue crack growth in PUR elastomers

2.1. Static tensile properties

According to the American Standards ASTM D412-16 (DIE C specimen type), ASTM 624-00 (DIE C specimen type), basic static mechanical properties were determined. The main results are collected in Table 1.

Table 1. Basic mechanical properties of tested PUR materials (static tensile test, tear resistance test) Property PUR80ShA PUR90ShA Ultimate Tensile Strength  UTS (MPa) 31.8 41.8 Critical strain at rupture  u (%) 419 422 Tear Resistance T (N/mm) 93.7 134.0  100% (Mpa) 3.7 7.4  200% (Mpa) 5.4 11.1  300% (Mpa)  7.0 15.1