TY - JOUR
T1 - Crack growth in a range of additively manufactured aerospace structural materials
AU - Iliopoulos, Athanasios
AU - Jones, Rhys
AU - Michopoulos, John
AU - Phan, Nam
AU - Singh Raman, R. K.
N1 - Funding Information:
Funding: Support for this work by the Office of Naval Research through the Naval Research Laboratory’s core funding was provided to co-authors A.I. and J.M.
Publisher Copyright:
© 2018, MDPI. All rights reserved.
PY - 2018/12
Y1 - 2018/12
N2 - The aerospace industry is now beginning to adopt Additive Manufacturing (AM), both for new aircraft design and to help improve aircraft availability (aircraft sustainment). However, MIL-STD 1530 highlights that to certify airworthiness, the operational life of the airframe must be determined by a damage tolerance analysis. MIL-STD 1530 also states that in this process, the role of testing is merely to validate or correct the analysis. Consequently, if AM-produced parts are to be used as load-carrying members, it is important that the da/dN versus ∆K curves be determined and, if possible, a valid mathematical representation determined. The present paper demonstrates that for AM Ti-6Al-4V, AM 316L stainless steel, and AM AerMet 100 steel, the da/dN versus ∆K curves can be represented reasonably well by the Hartman-Schijve variant of the NASGRO crack growth equation. It is also shown that the variability in the various AM da/dN versus ∆K curves is captured reasonably well by using the curve determined for conventionally manufactured materials and allowing for changes in the threshold and the cyclic fracture toughness terms.
AB - The aerospace industry is now beginning to adopt Additive Manufacturing (AM), both for new aircraft design and to help improve aircraft availability (aircraft sustainment). However, MIL-STD 1530 highlights that to certify airworthiness, the operational life of the airframe must be determined by a damage tolerance analysis. MIL-STD 1530 also states that in this process, the role of testing is merely to validate or correct the analysis. Consequently, if AM-produced parts are to be used as load-carrying members, it is important that the da/dN versus ∆K curves be determined and, if possible, a valid mathematical representation determined. The present paper demonstrates that for AM Ti-6Al-4V, AM 316L stainless steel, and AM AerMet 100 steel, the da/dN versus ∆K curves can be represented reasonably well by the Hartman-Schijve variant of the NASGRO crack growth equation. It is also shown that the variability in the various AM da/dN versus ∆K curves is captured reasonably well by using the curve determined for conventionally manufactured materials and allowing for changes in the threshold and the cyclic fracture toughness terms.
KW - 316L stainless steel
KW - Additive manufacturing
KW - AerMet100 steel
KW - Crack growth
KW - NASGRO
KW - Ti-6Al-4V
UR - http://www.scopus.com/inward/record.url?scp=85125283759&partnerID=8YFLogxK
U2 - 10.3390/AEROSPACE5040118
DO - 10.3390/AEROSPACE5040118
M3 - Article
AN - SCOPUS:85125283759
SN - 2226-4310
VL - 5
JO - Aerospace
JF - Aerospace
IS - 4
M1 - 118
ER -