PSI - Issue 56

Tamas Krausz et al. / Procedia Structural Integrity 56 (2024) 71–77 Krausz/ Structural Integrity Procedia 00 (2019) 000–000

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Table 1. The average and standard deviation values of the elastic modulus as function of temperature. Makrolon 2405 Makrolon 9415 Makrolon 8035 Average [MPa] St. dev. [MPa] Average [MPa] St. dev. [MPa] Average [MPa] St. dev. [MPa] 22 ° C 2600 305.16 4104 131 5723 469.88 40 ° C 2480 98.11 3930 275.45 5680 200.44 80 ° C 2260 184.73 3571 177.93 5295 118.32

In terms of the Poisson’s ratio one can observe that all three material grades show stability although the temperature increases (Table 2). There is a variation of about 3% for each grade, but there is no clear indication of negative temperature impact.

Table 2. The average and standard deviation values of the Poisson’s ratio as function of temperature. Makrolon 2405 Makrolon 9415 Makrolon 8035 Average [-] St. dev. [-] Average [-] St. dev. [-] Average [-] St. dev. [-] 22 ° C 0.418 0.067 0.414 0.014 0.343 0.083 40 ° C 0.43 0.041 0.421 0.03 0.336 0.086 80 ° C 0.431 0.02 0.403 0.041 0.332 0.06

3.2. The effects of thermal aging Figure 3 represents the engineering stress - strain curves in monotonic tensile testing of aged and non-aged polycarbonate, from all three selected grades. The curves of the aged specimens do respect the same tendency as the ones for the non-aged samples, however, high degrees of similarity can only be observed up to the yield limit (elastic region). Beyond this point the aged samples exhibit a sudden drop in terms of stresses opposed to the non-aged materials where the softening of the material happens more slowly. A flow of the material can then be observed for both specimen types until the deformations reach their maximum values before fracture occurs.

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Aged MK2405 Non ‐ Aged MK2405

Aged MK9415 Non ‐ Aged MK9415

Stress [MPa]

Stress [MPa]

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Strain [%]

Strain [%]