Comparison of Measured Temperatures, Thermal Stresses and Creep Residues With Predictions on a Built-up Titanium Structure
Jenkins, Jerald M. (1987) Comparison of Measured Temperatures, Thermal Stresses and Creep Residues With Predictions on a Built-up Titanium Structure. Technical Report NASA TM-86814, Research Engineering, NASA Dryden Flight Research Center.
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Abstract
Temperature, thermal stresses, and residual creep stresses were studied by comparing laboratory values measured on a built-up titanium structure with values calculated from finite-element models. Several finite-element models were used to examine the relationship between computational thermal stresses and thermal stresses measured on a built-up test structure. Element suitability, element density, and computational temperature discrepancies were studied to determine their impact on measured and calculated thermal stress. The optimum number of elements is established from a balance between element density and suitable safety margins, such that the answer is acceptably safe yet is economical from a computational viewpoint. It was noted situations exist where relatively small excursions of calculated temperatures from measured values result in far more than proportional increases in thermal stress values. Measured residual stresses due to creep significantly exceeded the values computed by the piecewise linear inelastic strain analogy approach. The most important element in the computation is the correct definition of the creep law. Computational methodology advances in predicting residual stresses due to creep require significantly more viscoelastic material characterization than is currently available.
| EPrint Type: | NASA Technical Memorandum |
|---|---|
| Keywords: | Creep, Heat transfer, Temperature, Thermal stress |
| Subjects: | (31 - 39) Engineering: (39) Structural Mechanics |
| ID Code: | 502 |
| Deposited On: | 19 January 2006 |
| Additional Information: | 27 pages. |
