PSI - Issue 13

Ondřej Krepl et al. / Procedia Structural Integrity 13 (2018) 1279 – 1284 Ond ř ej Krepl & Jan Klusák / Structural Integrity Procedia 00 (2018) 000–000

1283

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Table 1. Bi-material notch material properties.

Material

Young modulus [MPa]

Poisson ratio

Fracture toughness [MPa∙mm 1/2 ]

H 1c, m singular terms [MPa∙mm p 1 ]

H 1c, m non-singular terms [MPa∙mm p 1 ]

PMMA

2.3×10 3 69×10 3

0.38 0.33

32.26 758.95

65.83 182.33 12.66

64.24 196.41 12.39

Aluminum Interface

8.85

Fig. 3. Resulting distribution of averaged strain energy density factor.

5. Conclusions The multi-parameter SEDF criterion has been applied to the sharp material inclusion problem. For the studied geometry and bi-material configuration of this numerical example the difference in values of critical generalized fracture toughness predicted by singular terms or by singular and non-singular terms is the following: global minimum in PMMA 2.4 %, local minimum in Aluminum 7.7 % and 2.2 % in the interface. For this particular configuration, when the inclusion is more compliant than matrix, the increase in precision is rather small. However, there are configurations where employment of higher order terms increases the description of stress field significantly, inclusion stiffer than matrix, Krepl and Klusák (2017a). In such cases the employment of multi-parameter criterion to predict failure seems indispensable. However, there are particularities of such singularities which have to be studied more thoroughly as a subject of following work. Acknowledgements This research has been financially supported by the Ministry of Education, Youth and Sports of the Czech Republic under the project CEITEC 2020 (LQ1601). Financial support from the Czech Science Foundation (project No. 16 18702S) is gratefully acknowledged. References Pageau, S., Joseph, P., Biggers S., 1994. The order of stress singularities for bonded and disbonded three-material junctions, Int. J. Solid Structures 31, 2979-2997. Paggi, M., Carpinteri, A., 2008. On the stress singularities at multimaterial interfaces and related analogies with fluid dynamics and diffusion, Appl. Mech. Rev. 61, 1–22. Yang, Y., Munz D., 1995. Stress Intensity Factor and stress distribution in a joint with an interface corner under