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Journal of Failure Analysis and Prevention

, Volume 7, Issue 2, pp 144–151 | Cite as

Allowables-Based Flow Curves for Nonlinear Finite-Element Analysis

  • J. D. Pratt
Peer Reviewed
  • 69 Downloads

Abstract

A methodology for developing allowables-based stress versus strain relationships for metal alloys is presented. The approach incorporates Federal Aviation Administration/Department of Defense (FAA/DoD) Metallic Materials Property Development and Standardization (MMPDS) statistically derived material properties for tensile yield and ultimate strengths to derive flow curves at room or elevated temperature with an A-, B-, or S-Basis probability. The resulting flow curves may be used for new designs to comply with Federal Air Regulations as well as for forensic investigations and failure analysis.

Keywords

Materials allowables Finite-element analysis Material properties MMPDS Cozzone method Fictitious stress 

Notation

c

Distance from neutral axis to extreme fiber

e

Engineering strain

ep

Plastic strain

ePL

Strain at the proportional limit

eF

Strain at failure

eU

Strain at maximum load

eY

Strain at 0.2%-offset

E

Elastic modulus

f0

Fictitious stress

F

Allowables-based stress

FF

Allowables-based stress at failure

FM

Maximum allowable stress

FPL

Allowables-based stress at the proportional limit

FTU

Allowables-based stress at maximum load

FTY

Allowables-based stress at 0.2%-offset

I

Moment of inertia

M

Moment

P

Load

Q

Reduction of area at failure

S

Engineering stress

SF

Engineering stress at failure

SPL

Engineering stress at the proportional limit

SU

Engineering stress at maximum load

SY

Engineering stress at 0.2%-offset

ε

True strain

εF

True strain at failure

εp

True plastic strain

εPL

True strain at the proportional limit

εU

True strain at maximum load

εY

True strain at 0.2%-offset

σ

True stress

σF

True stress at failure

σPL

True stress at the proportional limit

σU

True stress at maximum load

σY

True stress at 0.2%-offset

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Copyright information

© ASM International 2007

Authors and Affiliations

  1. 1.Argos EngineeringLaguna NiguelUSA

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