Propagation of stress waves in thin orthotropic plates
2018
Klimenda, F., Jan Evangelista Purkyne Univ. in Ústí nad Labem (Czech Republic) | Soukup, J., Jan Evangelista Purkyne Univ. in Ústí nad Labem (Czech Republic) | Skocilasova, B., Jan Evangelista Purkyne Univ. in Ústí nad Labem (Czech Republic)
The article deals with the issue of longitudinal and transverse wave propagation in the body of the thin viscoelastic orthotropic plate of Glass-Epoxy composite material. The plate has dimensions 0.1 × 0.1 × 0.0005 m. This plate was circumferentially fixed and loaded by impact force 1 N in the centre of the plate (impact centre). The impact load was induced by the steel thin rod with spherical contact end. The radius of the rod c is 0.0025 m. For determination of the wave propagation of the plate the Kirchhoff model orthotropic plate, which is based on the Voight-Kelvin model, was used. The material properties of Glass-Epoxy are taken from literature material lists. These quantities are density, Poisson number, tensile modulus and shear modulus for x, y, and z directions. The calculation of displacements and velocities in the axes direction (x, y, z) was solved in MATLAB programme. The maximum calculation time reached 2 × 10E-5 s, the time step of the calculation was applied up to 2 × 10E-7 s. The waves are propagated from the impact centre in all directions. The wave propagation in x, y, z direction was determined at three points (B1, B2, B3 – position is presented in Figure 2) at a distance of 10 mm from the impact centre. The results, i.e. the displacements and the velocities at each observed point, are shown in Figures 3 to Figures 8. The coordinates of the points, in which the displacements and velocities were determined, are B1 [0.01; 0.00; 0.00], B2 [0.01; 0.01; 0.00] and B3 [0.00; 0.01; 0.00]. The results show that the velocity of the longitudinal wave propagation (i.e. in the x and y direction) is approximately 1.5 times greater than the velocity of a transverse wave dissemination (i.e. in the z direction). This result is in accordance with the wave theory.
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