Prestraining and its influence on subsequent fatigue life

Technical Report · Wed Mar 01 04:00:00 EST 1995

OSTI ID:147174

Halford, G R; Mcgaw, M A; Kalluri, S

An experimental program was conducted to study the damaging effects of tensile and compressive prestrains on the fatigue life of nickel-base, Inconel 718 superalloy at room temperature. To establish baseline fatigue behavior, virgin specimens with a solid uniform gage section were fatigued to failure under fully-reversed strain-control. Additional specimens were prestrained to 2 percent, 5 percent, and 10 percent (engineering strains) in the tensile direction and to 2 percent (engineering strain) in the compressive direction under stroke-control, and were subsequently fatigued to failure under fully-reversed strain-control. Experimental results are compared with estimates of remaining fatigue lives (after prestraining) using three life prediction approaches: (1) the Linear Damage Rule; (2) the Linear Strain and Life Fraction Rule; and (3) the nonlinear Damage Curve Approach. The Smith-Watson-Topper parameter was used to estimate fatigue lives in the presence of mean stresses. Among the cumulative damage rules investigated, best remaining fatigue life predictions were obtained with the nonlinear Damage Curve Approach.

• Research Organization: National Aeronautics and Space Administration, Cleveland, OH (United States). Lewis Research Center
• OSTI ID: 147174
• Report Number(s): N--96-12355; NASA-TM--106881; NAS--1.15:106881; E--9517; CNN: RTOP 584-03-11
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
FATIGUE
FRACTURE PROPERTIES
INCONEL 718
STRAINS