The Development Of Testing System For The Explosive Expansion Coefficient

"Expansion on heating and contraction on cooling" is the most common phenomenon of materials, which can be described by linear expansion coefficient. Linear expansion coefficient is one of the basic thermal physical parameters of materials by characterizing the important features on the material nature. The same is true of explosives. Thermal expansion performance of explosives is the premise of quality selection. Therefore, to accurately measure the linear expansion coefficient of explosives is particularly important. Supporting by the large literatures and the practical research, the principles and implementation of the testing system in the explosive expansion coefficient based on MCGS are proposed, and the system is developed. It's mainly used to measure the explosive expansion coefficient in a given temperature, and provide analytical basis for the technical staff. The main contents of the dissertation are listed here as follow:1. According to the actual analysis and principles, a design of testing system for explosive expansion coefficient based on MCGS is brought forward. The system mainly consists of furnace, sample room, temperature measurement module, temperature control module, expansion displacement measurement module and embedded system.2. The system adopts with the compressor and liquid nitrogen to cool down, while using electric resistance furnace to heat. Because of the delay and inertial characteristics of the resistance furnace system, studying on the system or other similar systems, and through the experimental and theoretical analysis, ultimately, the mathematical model for the system is established, which is identified and simulated. Meanwhile, the principle of the Internal Model Control-PID control algorithm is taken during development, which is conducted in the temperature control of the system.3. The system has the upper and lower computer mode. The lower computer completes all the tests on MCGS, including data collection, storage and management, control algorithm implemented, real-time communications of the upper and lower computer; the upper computer is mainly based on PC, using C++ Builder software development tools. PC is responsible for the Modbus RTU Communication Protocol, data transmission, storage, query and report print.Finally, the installation, debugging and experiment for the system is conducted. The results show that the system is able to accomplish the measurement of linear expansion coefficient of explosives and reach the technical indicator, such as temperature range is -50～ 80℃, the accuracy of temperature measurement can reach±0.1℃, the accuracy of the displacement measurement can reach±0.1um; the Internal Model Control-PID control algorithm can achieve good temperature control within±1℃in the system; the upper and lower computer mode can transfer data efficiently, storage and analysis data correctly.