Optimum Design Of Mechanical Properties Of Aluminum Sheets-with-ribs

Aluminum sheet-with-ribs is a stiffened plate contains several paralleled aluminum profile in a same direction which is made by extrusion process. Comparing with welded stiffened plate, sheet-with-ribs has great superiority. The use of aluminum extrusion profile and integral panel in high speed ships makes great progress in the fasting and lightening of transpotation both inland and offshore.With the extensive application of high strength material, it tends to be used in ship-building industry in the form of thin-walled and light structural members. The tensile stress of structures is no longer the prominent problem compared with the structure's buckling under compression. The phenomenon that structures lose carrying capability caused by buckling is increasingly outstanding and designers must take it into consideration. After buckling, the carrying capacity of structures decreases and the deformation increases seriously, whichever may cause serious consequence. How to decrease structural materials to the maximum extent, both in economy and security, has been an important subject in structure design.The mechanical property of the sheets with ribs has been studied in this thesis. For the design of the sheets-with-ribs,the economical and security criterion has been taken into consideration which may also satisfied the structure design rules of the high speed ships and a suitable sheet-with-ribs in the range of different transverse loads will be provided. The main work in this thesis is as follows:(1) Based on the knowledge of profile design, the optimum web height and sectional area of stiffener web and flange has been acquired through the preliminary design.(2) Finite element method has performed for the eigenvalue buckling analyses of sheets with ribs subjected to uniaxially compression. Adjust the web height to ensure that the elastic local plate buckling happens before overall panel buckling and the stress of overall panel buckling is twenty percent larger than that of local buckling. And then stress analysis is done when the sheets-with-ribs are under different transverse loads, and make sure that all the results are in the same stress level. Five kinds of aluminum sheets-with-ribs are designed according to these two aspects.(3)The rational of the five sheets-with-ribs has been validated through the comparison of the ultimate strength and the stress of overall panel buckling.