Papers by Keyword: Wave Form

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Authors: Qi Lei Sun, Lu Dan Shi, Ze Rui Liu
Abstract: With the example of stress corrosion test of natural gas pipeline steel, the application of Visual Basic (VB) language program in the test will be discussed in the paper. The result shows that different waveforms of VB language design can simulate various forms of applied load of pipeline steel well, and make fluctuant slow strain rate test more accurate and convenient.
Authors: Shigeto Takebayashi, Kohsaku Ushioda, Naoki Yoshinaga, Shigenobu Ogata
Abstract: The effect of tempering temperature on the impact toughness of 0.3 mass% carbon martensitic steels with prior austenite grain (PAG) size of about 6 μm and 30 μm were investigated. Instrumented Charpy impact test (ICIT) method was used to evaluate the impact toughness. The tempering temperature of 723K gives the largest difference in the Charpy impact energy at room temperature (RT) between the specimens with two different PAG sizes. Investigation of the test temperature dependence of Charpy impact energy in the 723K tempered steels shows a steep transition at around 200 K for the 6 μm PAG specimen, while it shows a continuous slow transition in a wide range of temperature for the 60 μm PAG specimen. ICIT waveform analysis shows that the fracture propagation energy in stead of the fracture initiation energy mainly controls the temperature dependence of the impact energy. The carbide size distribution in these two specimens was investigated by SEM and TEM. The 60 μm PAG specimen shows the distribution of coarser carbides than does the 6 μm PAG specimen, which seems to be the main reason for the observed difference between them in the Charpy impact energy and the other properties of impact fracture.
Authors: Ming Yan, Zhao Dong Wen, Jian Ye Du
Abstract: Horizontal shock testing table can be used to evaluate shock resistance ability of warship equipments. Based on this theory, the level of flexible plate oriented shock testing platform is raised. Using the finite element method, the output waveform of the testing platform and the stress distribution of the flexible plate are analyzed in this paper. It can be concluded that flexible plate can be used to store elastic potential energy during the impact and have a certain impact on test waveforms. Theoretical maximum displacement of the platform body is 94mm, the calculated value is 89.5mm, decrease by 4. 8%; theoretical maximum speed of the platform body is 4m/s, the calculated value is 3.93m/s, reducing to1.75%; theoretical, the value of positive wave peak acceleration of platform body is 571m/s2, the calculated value is 532 m/s2, decrease by 6.8%; theoretical platform body negative wave peak acceleration values is 175m/s2, the calculated value of 183 m/s2, an increase of 4.6%. The research shows that flexible plate as a guide device can meet the impact test table for error waveform requirements..
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