A new methodology to predict damage tolerance based on compliance via global-local analysis

Over the years several design philosophies to fatigue developed in order to combine structural safety and economy to manufacturing and operating aircraft process. The safe-life approach, which consists of designing and manufacturing a safe aeronautical structure throughout its useful life, results in factors that oversize the structural elements, preventing the possibility of failure and evidently leading to high design costs. On the other hand, the approach based on the damage tolerance concept, in which it is assumed that the structure, even whether damaged, is able to withstand the actions for which it was designed until the detection of a crack due to fatigue or other defects during its operation. Here, we propose a new methodology to the damage tolerance problem in which two-dimensional global-local analysis at different levels of external requests will be made by means of compliance, aimed at finding a relationship between fatigue life and the Paris constant. Moreover, the BemCracker2D program for simulating two-dimensional crack growth is used. This methodology has been proved to be an efficient and applied alternative in the damage tolerance analysis.

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Damage Tolerance Analysis of Cracked Stiffened Composite Panels

Journal of Composite Materials ◽

10.1177/002199801772661470 ◽

2001 ◽

Vol 35 (20) ◽

pp. 1815-1843 ◽

Cited By ~ 6

Author(s):

Puhui Chen ◽

Zhen Shen ◽

Junyang Wang

Keyword(s):

Damage Tolerance ◽

Tolerance Analysis ◽

Composite Panels ◽

Stiffened Composite Panels ◽

Damage Tolerance Analysis

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Micromechanics-Based Fracture Risk Assessment Using Integrated Probabilistic Damage Tolerance Analysis and Manufacturing Process Models

Volume 7B: Structures and Dynamics ◽

10.1115/gt2016-58089 ◽

2016 ◽

Cited By ~ 1

Author(s):

Michael P. Enright ◽

R. Craig McClung ◽

Kwai S. Chan ◽

John McFarland ◽

Jonathan P. Moody ◽

...

Keyword(s):

Grain Size ◽

Gas Turbine ◽

Manufacturing Process ◽

Damage Tolerance ◽

Random Variables ◽

Software Tool ◽

Tolerance Analysis ◽

Turbine Engine ◽

Damage Tolerance Analysis ◽

Time Required

Materials engineering and damage tolerance assessment have traditionally been performed as disjoint processes involving repeated tests that can ultimately prolong the time required for certification of new materials. Computational advances have been made both in the prediction of material properties and probabilistic damage tolerance analysis, but have been pursued primarily as independent efforts. Integrated computational materials engineering (ICME) has the potential to significantly reduce the time required for development and insertion of new materials in the gas turbine industry. A manufacturing process software tool called DEFORM™ has been linked with a probabilistic damage tolerance analysis (PDTA) software tool called DARWIN® to form a new capability for ICME of gas turbine engine components. DEFORM simulates rotor manufacturing processes including forging, heat treating, and machining to compute residual stress and strain, track anomaly location, and predict microstructure including grain size and orientation. DARWIN integrates finite element stress analysis results, fracture mechanics models, material anomaly data, probability of anomaly detection, and inspection schedules to compute the probability of fracture of a gas turbine engine rotor as a function of operating cycles. Previous papers have focused on probabilistic modeling of residual stresses in DARWIN based on manufacturing process training data from DEFORM. This paper describes recent efforts to extend the probabilistic link between DEFORM and DARWIN to enable modeling of residual strain, average grain size, and ALA (unrecrystalized) grain size as random variables. Gaussian Process modeling is used to estimate the relationship among model responses and material processing parameters. These random variables are applied to microstructure-based fatigue crack nucleation and growth models for use in probabilistic risk assessments. The integrated DARWIN-DEFORM capability is demonstrated for a representative engine disk model which illustrates the influences of manufacturing-induced random variables on component fracture risk. The results provide critical insight regarding the potential benefits of integrating probabilistic computational material processing models with probabilistic damage tolerance-based risk assessment.

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