PSI - Issue 28

L.A. Igumnov et al. / Procedia Structural Integrity 28 (2020) 1909–1917 Author name / Structural Integrity Procedia 00 (2019) 000–000

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Figs. 5 and 6 show the failure patterns of the shells with two-layered reinforcement scheme, the external layer of which was formed by ring winding and internal one by angle-ply winding at the angles ±30, ±45. The failure process of the shells of this type begins in external circular layer with subsequent failure of the bottom layer and final failure of the shells with ±45 reinforcement. Besides, the strain rate dependence taken into account does not lead to final failure of the shell.

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Fig. 5. Failure process of metal-plastic shells with reinforcement scheme (±30;90 0 )

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Fig. 6. Failure process of metal-plastic shells with reinforcement scheme (±45;90 0 )

Thus, the results obtained attest that the account of strain rate dependence of strength characteristics for all the reinforcement schemes considered lead to a qualitative difference in the character and size of failure zones of the binder and fibers and to a significant increase in the load-carrying capacity of the shells compared with the calculations of constant strength characteristics. On Fig.7, the calculated and experimental relations (Ivanov (1992)) for the maximum circumferential strains e 22 as functions of the specific explosive load m * ( m * =m/M O ), where M O is the weight of shell) for metal-plastic shells, the composite macrolayers of which are based on fiber-glass with (±45;90 0 ) reinforcement scheme. It is seen that the relations are linear and the metal-plastic shells in conditions of dynamic loading deform linearly elastically up to failure. The discrepancy between the theoretical and experimental results, growing with the relative weight of explosive charge, is apparently connected with the imperfect failure model. The results obtained testify to a high specific strength of pulse-loaded metal-plastic shells of revolution and well agree with experimental data (Rusak (2002)).