PREDICTION OF CREEP EFFECTS IN AIRCRAFT STRUCTURES
Abstract
A step-by-step numerical process for introducing thermal and creep effects into a redundant structural analysis was developed. This process involves seven consecutive steps: (1) elastic thermal stress determination; (2) unit displacement determination in terms of stiffness patterns; (3) relaxation increment determination; (4) real thermal stress determination resulting from summation of thermal and relaxation stresses; (5) incremental stress determination; (6) determination of stress redistribution attendant to creep; and (7) summation of elastic, thermal and creep stresses. Calibrations with model materials and structural elements, seeking verification of structural criteria introduced into numerical processes are demonstrated. An example problem for a delta wing illustrates method of calculation. The creep test independent variables, time, temperature and stress, were examined with reference to their influence upon the dependent variable, strain in fields of creep activity operative under conditions of (1) constant stress and constant temperature, (2) varying stress and constant temperature, and (3) constant stress and varying temperature.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 15, 1960
- Accession Number
- AD0261976
Entities
People
- C. Riparbelli
- C. W. Alesch
- W. Robe
Organizations
- General Dynamics