Reliability Analysis Of Ultimate Compressive Strength For Stiffened Composite Panels

The prediction and reliability assessment of ultimate compressive strength for stiffened composite panels are essential for safe structural design. The reliability assessment of ultimate compressive strength for stiffened composite panels is time-consuming. An efficiency reliability assessment method is proposed, and the results of reliability-based structural optimization influence on the ultimate strength are discussed in this paper. The main contents in this thesis are listed as following: 1. Progressive failure modelIn this paper, several composite stiffened panels FEM models are built by Abaqus software. The efficiency and accuracy of these models is discussed. A method which combines progressive stiffness degradation criterion with cohesive elements is used to simulate the failure progress. This method considers multiple failure modes, and the prediction results of ultimate strength are very accuracy.2. Linear reliability assessment method of composite stiffened panelsIn order to solve the problem of time-consuming for stiffened composite panels under axial compression is proposed. Therefore, the KPcr is use to replace the ultimate compressive strength Pu in the process of reliability evaluation to reduce the computational efforts in this paper. The relationship between KPcr and Pu.is verified by using the Taylor series and the classical RSM. The reliability results of stiffened composite panels which calculated by the proposed method are close to classical method. The proposed method is easy for practical engineering with the higher efficiency compare to classical method. 3. The influence of RBSO results on ultimate strengthA reliability optimization model base on buckling load and several deterministic optimization models are established in this paper. Optimist the thickness of stiffened panels by changing the objective function and constraint condition. The results show that:(1) the reliability optimization method which based on buckling load can guarantee the reliability of buckling load and ultimate load.(2) The results of reliability optimization and deterministic optimization show that the buckling load and ultimate load have great correlation. And the proposed method in the fourth chapter is reasonable and effective.