0
Research Papers: Gas Turbines: Structures and Dynamics

Strain Rate and Loading Waveform Effects on an Energy-Based Fatigue Life Prediction for AL6061-T6

[+] Author and Article Information
Todd Letcher

e-mail: etcher.7@osu.edu

M.-H. H. Shen

e-mail: shen.1@osu.edu
Mechanical and Aerospace
Engineering Department,
Building 148, 201 W. 19th Ave.,
The Ohio State University,
Columbus, OH 43210

Charles Cross

Turbine Engine Fatigue Facility,
Air Force Research Laboratory,
Wright-Patterson AFB, OH 45433

Contributed by the Structures and Dynamics Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received May 29, 2013; final manuscript received August 28, 2013; published online November 1, 2013. Editor: David Wisler.

J. Eng. Gas Turbines Power 136(2), 022502 (Nov 01, 2013) (6 pages) Paper No: GTP-13-1150; doi: 10.1115/1.4025497 History: Received May 29, 2013; Revised August 28, 2013

The energy-based lifing method is based on the theory that the cumulative energy in all hysteresis loops of a specimens' lifetime is equal to the energy in a monotonic tension test. Based on this theory, fatigue life can be calculated by dividing monotonic strain energy by a hysteresis energy model, which is a function of stress amplitude. Recent studies have focused on developing this method for a sine wave loading pattern—a variable strain rate. In order to remove the effects of a variable strain rate throughout the fatigue cycle, a constant strain rate triangle wave loading pattern was tested. The testing was conducted at various frequencies to evaluate the effects of multiple constant strain rates. Hysteresis loops created with sine wave loading and triangle loading were compared. The effects of variable and constant strain rate loading patterns on hysteresis loops throughout a specimens' fatigue life are examined.

FIGURES IN THIS ARTICLE
<>
Copyright © 2014 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Hysteresis loop in generalized coordinates

Grahic Jump Location
Fig. 2

Specimen dimensions

Grahic Jump Location
Fig. 3

Fatigue test setup using an MTS load frame

Grahic Jump Location
Fig. 4

Sinusoidal and triangular loading waveforms

Grahic Jump Location
Fig. 5

Hysteresis loop—sine wave, 241.3 MPa, 2 Hz

Grahic Jump Location
Fig. 6

Hysteresis loop—triangle wave, 241.3 MPa, 2 Hz

Grahic Jump Location
Fig. 7

Different specimen for stress level and waveform (refer to Table 1)

Grahic Jump Location
Fig. 8

Same specimen for each stress level (refer to Table 2)

Grahic Jump Location
Fig. 9

Cumulative energy over specimen lifetime

Grahic Jump Location
Fig. 10

Fatigue life predictions based on two loading waveforms on a single specimen

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In