Residual Strength of Aging Aircraft with Multiple Site Damage/Multiple Element Damage

AIAA Journal ◽  
10.2514/2.445 ◽  
1998 ◽  
Vol 36 (5) ◽  
pp. 840-847 ◽  
Author(s):  
L. Wang ◽  
W. T. Chow ◽  
H. Kawai ◽  
S. N. Atluri
Keyword(s):  
Residual Strength ◽  
Multiple Site ◽  
Aging Aircraft ◽  
Multiple Site Damage

Residual strength of aging aircraft with multiple site damage/multiple element damage

AIAA Journal ◽  
1998 ◽  
Vol 36 ◽  
pp. 840-847
Author(s):  
L. Wang ◽  
W. T. Chow ◽  
H. Kawai ◽  
S. N. Atluri
Keyword(s):  
Residual Strength ◽  
Multiple Site ◽  
Aging Aircraft ◽  
Multiple Site Damage

Modified Swift Criteria for Residual Strength of Multiple Site Damage Structure

2009 ◽  
Vol 417-418 ◽  
pp. 881-884 ◽  
Author(s):  
Jian Yu Zhang ◽  
Rui Bao ◽  
Bin Jun Fei
Keyword(s):  
Residual Strength ◽  
Yield Criterion ◽  
Fatigue Cracks ◽  
Tensile Load ◽  
Maximum Load ◽  
Alloy Sheet ◽  
Multiple Cracks ◽  
Multiple Site ◽  
Multiple Site Damage ◽  
Aluminum Panels

As more aircrafts reach or exceed their design life, it is becoming very important to research multiple cracks damage, especially the multiple site damage (MSD) in order to re-evaluate their service life and damage tolerance/durability performance. The existing of MSD may remarkably reduce the residual strength of an aerospace structural component than those with a singe lead crack. This study investigated the residual strength of aluminum alloy sheet with MSD through three types of aluminum specimens test. Aluminum panels with bare collinear constant diameter holes were chosen as specimens. After some constant amplitude tension-tension load cycles, the MSD were found in these specimens since there were multiple fatigue cracks emanating from the saw cuts of holes. The residual strength was recorded as the maximum load when every specimen was subjected to monotonically increasing tensile load until failure occurred. In different failure prediction criteria that were often used in engineering in order to evaluate the accuracy of these criteria, Swift criterion (ligament yield) criterion got more accurate prediction results than other criteria. Although Swift criterion was more accurate than some other criteria, its error was still big for some specimens. Two modified approaches were proposed in order to get more accurate and appropriate failure criterion for MSD structure.

scholarly journals Residual Strength Prediction of Aluminum Panels with Multiple Site Damage Using Artificial Neural Networks

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5216 ◽  
Author(s):  
Ala Hijazi ◽  
Sameer Al-Dahidi ◽  
Safwan Altarazi
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Residual Strength ◽  
Lap Joints ◽  
Multiple Site ◽  
Ann Model ◽  
Model Predictions ◽  
Multiple Site Damage ◽  
Artificial Neural ◽  
Aluminum Panels

Multiple site damage (MSD) cracks are small fatigue cracks that may accumulate at the sides of highly loaded holes in aging aircraft structures. The presence of MSD cracks can drastically reduce the residual strength of fuselage panels. In this paper, artificial neural networks (ANN) modeling is used for predicting the residual strength of aluminum panels with MSD cracks. Experimental data that include 147 unique configurations of aluminum panels with MSD cracks are used. The experimental dataset includes three different aluminum alloys (2024-T3, 2524-T3, and 7075-T6), four different test panel configurations (unstiffened, stiffened, stiffened with a broken middle stiffener, and bolted lap-joints), many different panel widths and thicknesses, and the sizes of the lead and MSD cracks. The results presented in this paper demonstrate that a single ANN model can predict the residual strength for all materials and configurations with high accuracy. Specifically, the overall mean absolute error for the ANN model predictions is 3.82%. Furthermore, the ANN model residual strength predictions are compared to those obtained using the most accurate semi-analytical and computational approaches from the literature. The ANN model predictions are found to be at the same accuracy level of these approaches, and they even outperform the other approaches for many configurations.

Residual Strength Research for Aluminum Alloy Sheet with Multiple Site Damage

2007 ◽  
Vol 348-349 ◽  
pp. 489-492
Author(s):  
Jian Yu Zhang ◽  
Chuan Sheng Wang ◽  
Rui Bao ◽  
Bin Jun Fei
Keyword(s):  
Aluminum Alloy ◽  
Residual Strength ◽  
Yield Criterion ◽  
Fatigue Cracks ◽  
Alloy Sheet ◽  
Average Stress ◽  
Multiple Site ◽  
Aluminum Alloy Sheet ◽  
Stress Criterion ◽  
Multiple Site Damage

This study investigated the residual strength of aluminum alloy sheet with multiple site damage (MSD) through three types of aluminum specimens test. Aluminum panels with bare collinear constant diameter holes were chosen as specimens. And there were saw cuts at both edges of all the holes. After some constant amplitude tension-tension load cycles, the MSD were found in these specimens since there were multiple fatigue cracks emanating from the saw cuts of holes. The residual strength was recorded as the maximum load when every specimen was subjected to monotonically increasing tensile load until failure occurred. The test results were compared with predicted residual strength results by five different failure prediction criteria that were often used in engineering in order to evaluate the accuracy of these criteria. The failure criteria included: fracture criterion, net ligament loss criterion, ligament yield criterion, CTOA/CTOD criterion and average stress criterion. Ligament yield criterion (Swift criterion) and average stress criterion got more accurate prediction results than other criteria.

Testing Study and Mechanics Analysis on Fatigue Life of MSD Structure

2014 ◽  
Vol 908 ◽  
pp. 269-272
Author(s):  
Jin Fang Zhao ◽  
Qun Zhao
Keyword(s):  
Fatigue Life ◽  
Crack Propagation ◽  
Fatigue Cracks ◽  
Multiple Site ◽  
Aircraft Structures ◽  
Testing Method ◽  
Aging Aircraft ◽  
Mechanics Analysis ◽  
Multiple Site Damage ◽  
Testing Reference

Multiple site damage (MSD) usually occurs in the form of some small fatigue cracks at several sites within aging aircraft structures. It is very important to study the fatigue life of this kind of structure. This paper used testing method to observe the phenomenon of crack propagation, to analysis the result of the crack propagation. It provides testing reference for the study on fatigue life of MSD structures. According to the analysis of fatigue life of typical structures, a series of valuable conclusions are obtained.

Residual Strength of Multiple-Site Damage Structure on Aged Aircraft Using Interactions of Dugdale-Type Cracks and Stable Tearing

2012 ◽  
Vol 487 ◽  
pp. 539-543
Author(s):  
Xiao Feng Xue ◽  
Yun Wen Feng ◽  
Qiang Qin ◽  
Yuan Sheng Feng
Keyword(s):  
Residual Strength ◽  
Yield Criterion ◽  
Test Results ◽  
Multiple Site ◽  
Collinear Cracks ◽  
Dugdale Model ◽  
Panel Model ◽  
Multiple Site Damage ◽  
Damage Structure ◽  
Stable Tearing

Abstract. This paper presents an investigation method of residual strength of Multiple Site Damage (MSD) panel. Both interaction between cracks and the effect of stable tearing are considered together. Dugdale model of collinear cracks is employed in the MSD panel model. Swift strip-yield criterion is used to judge whether the cracks linkup. Compared with the test results, numerical results of 9 different configuration MSD panels of 2024-T3 aluminum alloy are compared with the test results. The average relative error is -2.09％and root-mean-square error is 0.048. The agreement between analysis and experiment is shown to be reasonable.

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