PSI - Issue 39

Branko Nečemer et al. / Procedia Structural Integrity 39 (2022) 34 – 40 Author name / Structural Integrity Procedia 00 (2019) 000–000

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4. Comparisons of the experimental and computational results In this section, the comparisons between experimental and computational results is presented. The LCF tests and computational analyses were performed at five loading levels with maximum force varying from 600 N to 1400 N with the step of 200 N. The comparisons of the − fatigue-life curves for the re-entrant and rotated re-entrant auxetic specimens are presented in Fig. 7.

_ = 38083 −0 . 628

_ = 7434.5 −0 . 397

1000

1000

(a)

(b)

_ = 4071.5 −0 . 326

_ = 3625.7 −0 . 316

100

100

Experimental results Computational results

Experimental results Computational results

10

10

Am plitude force [N]

Am plitude force [N]

1

1

100

1000

10000

100

1000

10000

Fig. 7. − fatigue-life curves: (a) Re-entrant auxetic structure; (b) Rotated re-entrant auxetic structure From Fig. 7, a relative good correlation between experimentally and computationally determined fatigue life is evident. Some scatter was obtained at higher amplitude forces for both analysed auxetic specimens. As expected, the higher amplitude forces lead to the shorter fatigue lives and vice versa. In Fig. 8 , the comparison between experimentally and computationally determined failure paths is shown. Number of load cycles to failure - N [Cycle] Number of load cycles to failure - N [Cycle]

Computational analysis

Experimental test

(a)

(b)

Fig. 8. Comparison of the failure path: (a) Re-entrant auxetic structure; (b) Rotated re-entrant auxetic structure