Flaw Tolerance in Lap Shear Brazed Joints — Part 1 Investigation brings a better understanding of the failure mechanism in brazed joints containing defects

Content Provider	Semantic Scholar
Author	Flom, Yury Wang, Liqin
Copyright Year	2002
Abstract	Furnace brazing is a joining process used in the aerospace and other industries to produce strong permanent and hermetic structural joints. As in any joining process, brazed joints have various imperfections and defects. At the present time, our understanding of the influence of the internal defects on the strength of the brazed joints is not adequate. The goal of this three-part investigation is to better understand the properties and failure mechanisms of the brazed joints contain- ing defects. This study focuses on the be- havior of brazed lap shear joints because of their importance in manufacturing aerospace structures. In Part 1, an average shear strength capability and failure modes of the single lap joints are explored. Stainless steel specimens brazed with pure silver are tested in accordance with the AWS C3.2 standard. Comparison of the failure loads and the ultimate shear strength with the finite element analysis (FEA) of the same specimens as a func- tion of the overlap widths shows excellent correlation between the experimental and calculated values for the defect-free lap joints. A damage zone criterion is shown to work quite well in understanding the failure of the braze joints. In Part 2, the findings of Part 1 will be verified on the larger test specimens. Also, various flaws will be introduced in the test specimens to simulate incomplete braze coverage in the lap joints. Mechanical testing and FEA will be performed on these joints to verify that behavior of the flawed ductile lap joints is similar to joints with a reduced braze area. Finally, in Part 3, the results obtained in Parts 1 and 2 will be applied to the actual brazed structure to evaluate the load-carrying capability of a structural lap joint containing discontinuities. In addi- tion, a simplified engineering procedure will be offered for the laboratory testing of the lap shear specimens.
File Format	PDF HTM / HTML
Alternate Webpage(s)	https://app.aws.org/wj/supplement/WJ_2004_01_s32.pdf
Alternate Webpage(s)	https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20030020926.pdf
Alternate Webpage(s)	https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20030025707.pdf
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article