Investigations of pre-stress effects on composite plates under the low-velocity impact

The purpose of this thesis is to evaluate pre-stress effects of composite plates under the low-velocity impact. In engineering applications, especially during manufacturing, installation, maintenance and usage processes, an unexpected results may occur against any outside impact. To prevent this, the behavior of the material against these effects can be estimated by impact tests. To estimate these effects, event has to be modelled in laboratory. For this pupose, the experiments were made in the machine laboratory by the low-velocity impact test device which is manufactured in TUBITAK career project. The sample was prepared as a Epoxy-Glass fiber reinforced composite [0 / 90] 2s orientated, 8 layered symmetric composite plate and it?s average thickness is 2mm. The size of the samples are taken as 140x140mm. After applying 2kN, 4kN and 6kN of unloaded and pre-stressed (tension-tension, tension-compression, compression- compression) forces, impact tests were made under 23.6 Joule energy. The graphical results were created by transferring the data to the computer with a piezoelectric sensor which is placed between the end shooters and the weightAs a result, the change maxsimum force, in the absorbed energy and collapse of the pre-stress on the composite plate under low-velocity impact.Key Words: Low-velocity impact, Pre-stress, Composite plates.