Design methods for structures under thermal ratchet

Conference · Wed Jan 01 04:00:00 EST 1975

OSTI ID:4011782

Branca, T R; McLean, J L

Previous work on the thermal ratchet analysis of a simple pipe is extended to the case of an intersection of a pipe with a spherical shell. The chosen nozzle configuration is subjected to an internal pressure which remains constant, and a cyclic thermal transient which is representative of the type of transient that might be expected for components of a LMFBR. A number of cross- sections through the nozzle were examined, each yielding a different combination of elastic primary and secondary stress. These stresses, together with their associated cyclic strain growth, as determined from an elastic-plastic-creep analysis of the nozzle, were then plotted on a Miller or Bree-type diagram. Thus, a number of points, one for each cross-section considered, were available for comparison with the data obtained from the ratchet analysis of simple pipe sections. Both the elastic and inelastic analyses on the nozzle were performed using the finite element method of structural analysis of the ANSYS computer code. The pipe ratchetting cases were computed using the Oak Ridge National Laboratory PLACRE code. For a sample pipe ratchet case, a brief comparison is given between the version of ANSYS used in this study, the ANSYS version used in the previous work and the PLACRE code. The three programs did not yield identical results. Further study is needed to resolve the discrepancies that were observed. The results of the comparison between the nozzle ratchet and pipe ratchet solutions indicate that reasonable predictions can be made for the nozzle ratchet strains based on elastic parameters and design curves developed from pipe ratchetting solutions. (auth)

• Research Organization: Teledyne Materials Research, Waltham, MA
• NSA Number: NSA-33-026767
• OSTI ID: 4011782
• Country of Publication: United States
• Language: English

Related Subjects

*LMFBR TYPE REACTORS-- REACTOR COMPONENTS
*STAINLESS STEEL-304-- THERMAL STRESSES
360103* --Materials--Metals & Alloys--Mechanical Properties
A CODES
COMPUTER CODES
CREEP
DESIGN
FINITE ELEMENT METHOD
LIQUID METALS
N50230* --Metals
Ceramics
& Other Materials--Metals & Alloys--Properties
Structure & Phase Studies
NOZZLES
P CODES
PIPES
PRESSURE DEPENDENCE
SODIUM
STRAINS