Corrosion Fatigue of a Marine Aluminum Alloy (5456-H343) in the Presence of Shallow Cracks
Abstract
Marine aluminum alloy 5456-H343 is a candidate primary structural material for naval high performance ships. This material in the form of 1/8 inch sheet was used to obtain initial alternating surface stress v cycles to failure data in air and salt water. Room temperature tests were performed using deflection controlled fully reversed bending at 30 Hz. Data was obtained for smooth and shallow, sharply notched specimens for fatigue lives up to 10 million cycles. Notches were semi-elliptical surface cracks with depths equal to .002 in., .0115 in., and .025 in. 5456-H343 showed excellent corrosion fatigue resistance in salt water, with increasing environmental sensitivity in the range of 1-10 million cycles. The material exhibits some notch sensitivity at a fatigue life of 10 million cycles. The following fatigue design/failure criterion were developed: (1) for shallow cracks less than .001 in. deep, the maximum fatigue stress is determined by endurance limit or fatigue strength of smooth specimens, and (2) for shallow cracks greater than .020 in. deep, the maximum fatigue stress is determined by the threshold or allowable stress intensity factor of notched specimens.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1978
- Accession Number
- ADA072562
Entities
People
- Terrence L. Tinkel
Organizations
- Naval Postgraduate School