Failure Probability Of Stiffened Plate Structure Under Blast Loading

The study of response and failure probability of structure has important meaning. Taking the common cross stiffened plate structure of the ship as the research object, this thesis carries on exploration and analysis of the ultimate deformation and failure probability of cross stiffened plate structure under the blast loading using theoretical analysis and numerical simulation. The main contents are as follows:(1) Based on first-order second-moment method, the own probability distribution of random variable is converted into standard normal distribution, coordinate rotation made, and then approximate expression of higher order approximation of structural performance function using Taylor expansion in the checking point is obtained; One-variable polynomial is decomposed, undetermined coefficient fitted by least square method; one-variable numerical integration is used to obtain advanced response surface method calculating failure probability.(2) The stiffened plate converted into equal rectangular steel plate, the theoretical analysis about the limit deformation of the clamped rectangular steel plate subjected to blast loading is conducted with the principle of energy conservation. And considering the influence of the bend moment and membrane force effect on the deformation of rectangular steel plate in the process of the deformation of rectangular steel plate, the deflection surface function is founded, and the bending deformation energy of the plastic hinge line and the protracting deformation energy in the plane are deduced, and the theoretical calculating formula of the plastic deflection is derived. Validated with some examples, the calculating data comply well with the numerical simulation and experimental results.(3) Based on failure criterion of displacement ductility, advanced response surface method set up in this paper is used to calculate failure probability of equivalent steel plate, which has better tally with other result.(4) This thesis takes the explosive density and yield strength of plate as the basic random variable, when there is less sample size fitting method is used, and random number generator is used to obtain 50 initial value of random variable. Limit deformation of cross stiffened plate structure is obtained by numerical simulation, and limit deformation is verified whether it obeys normal distribution. If it submits to normal distribution, probability density function of limit deformation is fitted using maximum entropy method, and then failure probability of cross stiffened plate structure is obtained.