13th International Conference on Fracture June 16–21, 2013, Beijing, China -1- Analysis and residual strength prediction for multiple site damage in aircraft structures by using weight function method X.R. Wu*1,2, W. Xu2,3, H. Wang2 1 AVIC Beijing Institute of Aeronautical Materials, Beijing 100095, China 2 School of Aeronautics and Astronautics, Shanghai Jiao Tong University, Shanghai 200240, China 3 School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China * Corresponding author: xueren.wu@gmail.com Abstract This paper presents a review of recent progress of the development of weight function method for analyzing multiple site damage in aircraft structural panels. An analytical method, the Weight Function Method (WFM), has been proposed and further developed to analyze the MSD problems and to determine the related various fracture mechanics parameters. The plastic zone sizes and crack opening displacements were extensively verified and validated by excellent agreement with available analytical and finite element method results. Combined with Crack Tip Opening Angle criterion (CTOA), the present WFM is employed to predict the stable crack growth and residual strength of aircraft aluminum sheets containing MSD. The predicted results compared very well with the corresponding experimental data. Thereby a novel analytical approach with high efficiency and reliability has been devised for MSD analyses in aircraft structures. Keywords：Multiple site damage, Weight function method, Plastic zone size, Crack opening displacement, Residual strength. 1. Introduction Multiple Site Damage (MSD) has been a serious threat to modern transport airplane structure safety, and therefore has become a great concern in aircraft damage tolerance design and airworthiness certification. A historical milestone case of this type of failure was the in-flight disintegration of a 5.5m long piece of the pressure cabin skin of upper fuselage of Aloha Airlines Boeing 737-200 over Hawaii in 1988 [1]. After the Aloha accident, all the major commercial airplane manufacturers were required to evaluate their aircraft for MSD in the critical areas of the wing, empennage and pressure fuselage [2]. Various models and methods [3-5] have been developed to determine the stress intensity factors, plastic zone sizes and crack opening displacements for the prediction of the fatigue life and residual strength for structures with MSD. Most current approaches rely mainly on advanced numerical techniques, especially the Finite Element Method (FEM). Despite its powerfulness, reliable FEM solutions for MSD require great efforts, time and experience in modeling and computation. Classical analytical method, e.g. the complex variable method, is limited to idealized MSD configurations. Recently, the Weight Function Method (WFM) has been proposed and further developed by the authors to analyze various fracture mechanics parameters and stable crack growth of sheets with MSD[6-10]. It is shown to be versatile and cost-effective for tackling sheets with MSD problems. The approach is outlined in this paper. 2. Weight function method for fracture parameters analysis for collinear cracks
RkJQdWJsaXNoZXIy MjM0NDE=