Study On Software Development And Design On Model Selection Of Expansion Joints In The Pipe Network

As a thermal compensation device, bellows expansion joints can compensate for the pipeline's thermal growth and the equipment's movement, and absorb the pipeline's vibration, which have characteristics such as simple assembly, good airtightness, a small area coverage, durability, reliable quality, large compensation quantity, and so on. Expansion joints are widely used in many fields such as aeronautics and astronautics, nuclear power industry, petrochemical, water conservancy project, urban construction, electric power, metallurgy, etc. In general, expansion joints are used to compensate for complex displacement, which can be classified axial movement, lateral deflection, and angular rotation. The expensive main anchors will be needed for huge pressure thrust in expansion joints bring forces and moments to supports of the pipe in different directions. So, it is economical to use some expansion joints in some occasions which can balance themselves. In a word, there are many types of expansion joints to be selected, for example, constraint type and free type, axial type, lateral type and angular type, internal pressure type and external pressure type. It is especially important to select the right type of expansion joint during designing the pipe network. Otherwise, there exists hidden trouble, even tragedy. Such cases are legion. While the calculation is a multifarious course, designers are eager to use correlative software to alleviate their working strength, to improve design efficiency and to shorten design cycle. This paper studied design and selection types of expansion joints in the pipe network, and prepared a corresponding program according to Standards of the Expansion Joint Manufacturers Association (EJMA, 2003). The major contents are as follows: 1. Based on a great deal of domestic and foreign documents, the piping network was divided into several typical pipe segments, which were straight pipe, П-shape pipe, T-shape pipe, L-shape pipe, plane Z-shape pipe, space Z-shape pipe. The methods on type selection of expansion joints in each pipe segment and calculation support reaction of each method were put forward. 2. The program realized calculation support reaction of typical pipe segments on flat of Windows with Visual Basic 6.0. 3. The database files were compiled with Microsoft Access. The query data and transfer data of the system was finished by ADO DATA technology. The connection with data can be established quickly by ADO (ActiveX Data Objects), and the DMBS program can be compiled with the least code. 4. The system realized the connection of Visual Basic and Microsoft Word with interface program. It realized opening the electronic document and input results into corresponding cells of the table. At last, it was convenient for the user to modify, save, and print the file. 5. The experiment was done according to China National Standard GB4334.8-84"Stainless Steel 42% MgCl2 Solution Stress Corrosion Method". It proved that the different stainless steel bellows made from different material had the different anticorrosion property. It provided a basis for economically choosing right material of bellows under different environment.