298Curved Glass Panel

In this example, a curved glass panel with base or projected dimension of 1500 mm x 1500 mm, radius of 1500 mm, Young's modulus of 70,000 MPa, Poisson's ratio of 0.22 and thickness of 8 mm, and under uniform lateral load is analyzed (see Figure 29.13). The longitudinal boundaries are hinged and immovable, while the curved edges are restrained in the longitudinal direction. Due to symmetry, only a quarter of the panel is analyzed with mesh size of 10 x 10. In Figure 29.14, we can see the load-deflection path at the plate center and the failure loads for annealed glass and tempered glass under positive and negative pressure. Failure is assumed when the maximum principal tensile stress reaches the characteristic strength of 14.25 MPa, which is calculated from Equations 29.4 and 29.5. For tempered glass, the failure stress is assumed to be four times the value for annealed glass [12].

From the figures, it can be seen that the failure pressure ratio for annealed and tempered glasses is the same as the ratio of their stresses where the geometrical change is not significant. However, for compressive load case, the failure pressure ratio for annealed to tempered glasses may not be equal to the ratio of their failure stresses. This is due to the large change in geometry resulting in the nonlinearity between the stress and the load.

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