Prediction Of Creep Effects In Aircraft Structures

Item

Title
Prediction Of Creep Effects In Aircraft Structures
Description
The method presented in WADD TR 60-411 Part I for predicting deformations in aircraft structures undergoing creep is reviewed. Modifications and simplifications of this method are considered and a simplified version of the original method is presented. Box beam tests were used to investigate the simplified method. The outcome of these tests indicated the accuracy of the method in predicting deformations in aircraft structures undergoing creep was in the same order of accuracy as that usually experienced in redundant analysis procedures.

The power law for expressing creep relations is found redundant in solution. Its usefulness appears chiefly in the display of creep test data. Current creep prediction methods, such as the Larson-Miller and Manson Haferd methods, appear as linearizing approximations for creep-relations with the result that inaccuracies in predicting very long and very short creep life restrict their usefulness. An approach to creep prediction based on creep-rupture history for establishment of creep laws is proposed. Relationships between tension - and creep - test data are examined experimentally with respect to single and repetitive load applications. general relationships are examined with the outcome that a general approach to creep prediction in all metallic materials appears improbable.
Date
1962
Index Abstract
Contrails and DTIC condensed
Photo Quality
Incomplete
Report Number
WADD TR 60-411 Part 2
Creator
Alesch, C. W.
Klein, B.
Robe, W.
Corporate Author
Convair, A Division of General Dynamics Corporation Engineering Department
Laboratory
Flight Dynamics Laboratory
Extent
218
Identifier
AD0277163
AD0277163
Access Rights
ASTIA
Distribution Classification
1
Contract
AF 33(616)-6567
DoD Project
1367
DoD Task
14002
DTIC Record Exists
No
Distribution Change Authority Correspondence
PER WL/AFSC (IST) ltr
Abstract
The method presented in WADD TR 60-411 Part I for predicting deformations in aircraft structures undergoing creep is reviewed. Modifications and simplifications of this method are considered and a simplified version of the original method is presented. Box beam tests were used to investigate the simplified method. The outcome of these tests indicated the accuracy of the method in predicting deformations in aircraft structures undergoing creep was in the same order of accuracy as that usually experienced in redundant analysis procedures.

The power law for expressing creep relations is found redundant in solution. Its usefulness appears chiefly in the display of creep test data. Current creep prediction methods, such as the Larson-Miller and Manson Haferd methods, appear as linearizing approximations for creep-relations with the result that inaccuracies in predicting very long and very short creep life restrict their usefulness. An approach to creep prediction based on creep-rupture history for establishment of creep laws is proposed. Relationships between tension - and creep - test data are examined experimentally with respect to single and repetitive load applications. general relationships are examined with the outcome that a general approach to creep prediction in all metallic materials appears improbable.
Report Availability
Full text available by request
Date Issued
1962-02
Provenance
IIT
Type
report
Subject
Airframes
Aerodynamic Loading
Deformation
Mathematical Prediction
Loading (Ordnance Projectors)
Creep
Cobalt Alloys
Chromium Alloys
Steel
Elastic Properties
Structures
Mathematical Analysis
Publisher
Wright-Patterson Air Force Base, OH : Flight Dynamics Laboratory, Aeronautical Systems Division, Air Force Systems Command
Format
xii, 218 pages : ill. ; 28 cm.
Distribution Conflict
No