Strength And Stability Analysis And Structural Design For Multi-stiffened Plates

Stiffened steel plate are the basic structure members in ship and offshore structures. Due to their simplicity in fabrication and excellent mechanical property, stiffened steel plates are also widely used in bridge, construction, aviation spaceflight and so on. With the trend of the development of the ship and lightness, the usage of high strength material and minishing the plate thickness can make prominent effect towards lightening the structural weight. But this will cause the stability of plate , local strength and welding deformations. So inland river high-speed ship adopts multi-stiffened plate hull structures. Adopting this structure in design, the plate size between its lengthways and transverse stiffeners is smaller than the conventional stiffened panel, so the designer can select thin plate to minish structural weights and can ensure their mechanical property.Because in currently domestic and international shipping fabrication criterion about the structure form recommended is the longitudinal framework type, and it is different from multi-stiffened plate structure. The designers pre-elect interrelated members according to their experience. This will bring inconvenience and uncertainty factors. Therefore, it is important to research the multi-stiffened plate mechanical property of strength and stability.After reviewing the orthotropic plate theory, the thesis summarizes the results of former researchers about stiffened plate and grillage. The thesis chooses many multi-stiffened plates, which are different in plate thickness, stiffener form, aspect and stiffener stiffness ratio, to carry on a series of finite calculation. According to interrelated theory and criterion, after analyzing and fitting curve the results, the thesis derives some modified formulas for multi-stiffened plate stiffener section modulus and effective shear area. With regard to stability, the thesis draws the conclusion for plate stability of the multi-stiffened plate structure. And based on the stability theory of continues-beam with internal elastic supports, the paper derives the calculation formula for the critical loads of multi-stiffened plates under axialcompressed force.At last, the thesis gives some examples to illustrate the formulary reliability. From the numerical solution compared with FEM results, it shows that the presented formula can give good results. It can be used in design and calculation for the multi-stiffened plate structures.