REGULARITIES OF DISPERSION OF ENDURANCE LIMIT OF STRUCTURAL ALUMINUM ALLOY (ZAKONOMERNOSTI RASSEYANIYA PREDELA VYNOSLIVOSTI KONSTRUKTSIONNOGO ALYUMINIEVOGO SPLAVA),
Abstract
Gauss and Weibull distribution functions are used for calculating the distribution of endurance limits for aluminum AV structural alloy. The calculations are based on the results of endurance tests of 1510 specimens 8 mm in diameter subjected to cantilever bending at 6000 rpm with maximum stresses of 23, 20, 18, 16.5, 15 and 13 kg/sq mm. Statistical analysis of the test data indicates that a normal distribution law is applicable to these results and that Weilbull distribution is contradictory in this case. The scatter of the endurance limits depends on the number of test cycles: as the number of cycles is increased, the spread in the endurance limits decreases. The coefficient of variation for the endurance limit is several times greater than the coefficient of variation for the breaking point. The uniformity of the alloy, and consequently the safety factor, is considerably dependent on the alloy structure. An increase in the degree of recrystallization of the alloy reduces the mean endurance limit and noticeably increases the scatter in endurance characteristics. Contamination of the alloy by oxide films has a similar effect on the endurance characteristics. Therefore, it is extremely important to use an alloy with a nonrecrystallized structure for critical parts operating under variable loads. Data on the distribution of the endurance limits for a material may be used for selecting the safety factor in strength calculations under variable loads. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 08, 1967
- Accession Number
- AD0670117
Entities
People
- M. N. Stepnov
Organizations
- National Air and Space Intelligence Center