PSI - Issue 28

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

1912

4

Fig. 1. Circumferential strains vs. time at α 1 =L/2 and α 3 =h/2 :  – experimental results (Rusak (2002)); numerical calculations of homogeneous glass-fiber-reinforced plastic (–  –), metal-plastic shells on the basis of glass fiber (—)

Tables 2-4 present the results of comparative numerical and experimental analyses of the ultimate strain and progressing failure processes of glass-fiber-reinforced plastic and metal-plastic shells with different reinforcement structures. The experimental results (Ivanov (1992)) are shown in the numerator and numerical calculations — in the denominator; e 22 is the maximum circumferential strain in the central section on the external surface of shell, and t is the time of strain attainment; T is the period of radial vibrations corresponding to their lowest mode. From an analysis of the results given in Tables 2 and 3 it follows, that, for glass-fiber-reinforced plastic shells, the ultimate strain and specific strength increase if a steel shell is inserted inside the composite shell. In this case, the shells with an annular reinforcement scheme failed at lower ultimate strains as compared with annular and spiral elementary layers.

Table 2 – Calculation Results and Experimental Data for the Homogeneous Glass-Fiber-Reinforced Plastic Shells

Condition of the shell Experiment Calculation

Reinforcement structure

R , m

m , g

e 22 , %

t , ms

T , ms

h/R, %

Failed in the third period of vibration in compression

0.1546

6.02

208

2.15/2.56

73/62

195/-

Failed in the first period of vibration in compression Failed in the third period of vibration in compression Failed in the first period of vibration in compression Failed in the first period of vibration in compression Failed in tension

(±65;90 0 )

0.1548

6.19

264

2.20/3.16

75/64

205/-

0.1549

6.38

466

3.9/4.5

70.0/43.9 -/-

Failed in tension Failed in tension

0.1547

6.06

483

5.20/4.82

75.0/41.6 -/-