Study On The Automatic System For Measuring Fatigue Crack Growth Rates And Thresholds

According to the standard (GB 6398?6) test method for fatigue crack growth rates of metallic materials and its appendix C ?the standard test method for fatigue crack growth thresholds of metallic materials, basing on the theory of fatigue crack growth and combining with the technology of mature digital梒ollection, we studied the automatic system and the experiment technique for measuring the fatigue crack growth rates and thresholds. In this paper, We studied and developed a set of automatic system for measuring the fatigue crack growth rates and thresholds of metallic materials. It included a data梒ollection hardware system that has considerable precision and good stability and a data processing software system that is powerful and easy梩o梪se. Using the system, we studied the experiment of measuring the fatigue crack growth rates and thresholds of steel 4OCrNiMo and obtained the fatigue property of steel 4OCrNiMo. From the experiment we proved that the stability and precision of the system are accorded with the standard requirement. We worked over the important experiment techniques such as circle梩ime recording, zero? change repairing, crack梥ize counting, load梤atio controlling. The system supplied a project for reconstructing old fatigue experiment? device. It is cheap, practical and advanced, so we concluded that it is worthy of generalizing and using.