Calendar Details

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Wednesday, August 28

NOTE: SEMINAR CANCELLED
Analysis Techniques for Multiaxial Fatigue Delamination in Composite Laminates

Jifeng Xu, Beijing Aeronautical Science and Technology Research Institute, Beijing, China
Materials Science and Technology Division, Mechanical Properties and Mechanics Group, Seminar
10:00 AM — 11:00 AM, High Temperature Materials Laboratory (Building 4515),
Room 265
Contact: Jy-An John Wang (wangja@ornl.gov), 865.574.2274

Abstract

Composite materials are increasingly used in modern aircraft structures. Fatigue damage prediction of composite materials and structures is still a challenging problem despite tremendous progress made during the past decade. Two critical problems should be considered for fatigue analysis of composite aircraft structures. One is that most structures made of composite materials are subjected to mixed- mode loading in realistic situations. Compared to pure mode cases, the prediction of mixed-mode delamination is much more complex, due to the complicated underlying failure mechanisms. The second issue is the stochastic nature of the fatigue process of mechanical components under service loading. Traditional damage analysis and modeling of aircraft structures assumes a deterministic damage accumulation process where deterministic crack growth curves, constant material properties, and specific initial flaw sizes are used. However, probabilistic life prediction and risk assessment is of critical importance for the safety of aircraft structures. In this presentation, a general multiaxial fatigue life prediction method for composite structures is delineated, and a validation process is described. Then an advanced uncertainty quantification and propagation methodology is explained. Finally, a fatigue life prediction model to yield the probabilistic fatigue damage prognosis and predict service life for composite aircraft structures is explored. Verification with extensive experimental data available in the literature is presented to demonstrate the validity of the proposed methodology. Generally good agreement is observed between the model predictions and experimental observations.

Meet the Speaker
Please contact Jy-An Wang to schedule an appointment with Dr. Xu and the senior managers and technical staff who will accompany him on this visit to ORNL, including Fuguang Qin, President of the Beijing Aeronautical Science & Technology Research Institute.