The research project PRÜFgbGLAS at Technische Universität Dresden developed a method to determine the bending strength of thermally curved glass with the four-point bending test. The testing procedure as well as the calculation base are closely referring to the EN 1288-3, which regulates the determination of the bending strength of flat glass. However, parameters, such as the bending radius or the chord length of the glass specimens, as well as a practical realisation in the industry have to be taken into account. During the project over 360 specimens were tested with recording the strain at the tensions side and the input force. The examined glass thickness ranges from 3 mm to 12 mm, the bending radii from 400 mm to 2000 mm. Besides, four specimens were tested non-destructively on different testing machineries in collaboration with the four specialists from the glass bending industry.
This article gives a practical overview over the application of the new aspects to perform a four-point bending test on a thermally curved glass specimen. It describes the specimen measurement and the modification of the testing rig for testing small bending radii and discusses the results of the additional tests on different testing machineries.