Development of a strain and optical velocity measurement system for high speed impact test device

High-speed impact testing (HSIT) devices are preferred today for detailed characterization of materials. What meant by the term "characterization" herein is the interpretation of the analysis based on the material strength of the sample after impact tests. The literature review puts forth a need for the development and enhancement of models within the scope of materials used for military purposes, especially in the defense industry. It is necessary to test sample materials at quantities enough to allow interpretation in high-speed impact testing devices in order to meet this need. Measurement systems are one of the key elements in the interpretation during the test phase. These measurement systems are divided into two: velocity and strain measurement systems. The Split-Hopkinson Pressure Bar (SHPB), also known as the Kolsky bar, is the generic name for high-speed impact testers. In this thesis, the development stages of the optical velocity measurement system and the strain measurement system for the mentioned impact testers are experimentally examined. The relevant experimental studies on drop weight impact testing devices, which can be tested at lower speeds than high-speed impact testing devices, are cited and interpreted. A transition wave is obtained by using optical sensors that can capture the transition of strike bars with an optical velocity measurement system. When the points where the set distance starts and ends in order to detect this transition wave are referred to as optical gates, the terms of first optical gate and second optical gate are used. The transition times can be measured by optical sensors and the speed of system can thus be measured. Strain-gauge sensors are used for the strain measurement of the system.