PSI - Issue 18

404 6

Boris Fedulov et al. / Procedia Structural Integrity 18 (2019) 399–405 Boris Fedulov and Alexey Fedorenko / Structural Integrity Procedia 00 (2019) 000–000

Fig. 5. Damage parameter distribution with middle crack after 100 iterations

Fig.6 shows the initial and final field of normal contact stresses in delamination area. It is possible to see that values increased after buckling approximately ten times.

Fig. 6. Contact pressure (Pa).

6. Conclusion The algorithm to estimate residual strength of the composite part subjected to the low velocity impact was performed. The advantage is that the approach avoids direct modelling of the impact process. The core idea of the method is the search of the worst damage distribution inside the area of the material affected by impact stresses. It was shown that the problem is identical to the topology optimization one but with opposite purpose to minimize stiffness of the structure. Examples with pure damage, middle crack and offset crack were analyzed. The corresponding damage parameter distributions were shown for each example problem. It was found that different values of applied load has to be analyzed due to the possible buckling of the specimen. Filtering technique based on neighbor distance similar to topology optimization algorithms to suppress checkerboard instability might be useful for the proposed algorithm. Block nature of the performed approach lets us to take into account more knowledge about defects from experimental statistics and reduce conservatism systematically, and eventually build an ideal BVID defect for design and development purposes in structural engineering.