Low cycle thermo-mechanical fatigue: damage operator approach

ABSTRACTPiezoelectric films for a MEMS microengine have been deposited using solution deposition routines onto platinized silicon wafers. These films are used as membranes above a bulk micromachined cavity. A dynamic bulge tester and interferometer were used to characterize the deformation of the films when pressurized. The mechanical strain at failure, as well as the fatigue behavior, have been characterized. Membranes between 300 and 500 nm thick have been shown to sustain mechanical fatigue damage over approximately 10 million cycles at strains of 30% of the monotonic failure strain. Defects in the films due to growth and thermal stresses during processing, and their role in membrane failure, are identified. Crack growth is demonstrated in these films by compliance measurements during fatigue testing, and interfacial failure is identified between the PZT and Pt layers.

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A time-dependent damage operator approach to thermo-mechanical fatigue of Ni-resist D-5S

International Journal of Fatigue ◽

10.1016/j.ijfatigue.2010.11.009 ◽

2011 ◽

Vol 33 (5) ◽

pp. 692-699 ◽

Cited By ~ 35

Author(s):

Marko Nagode ◽

Frank Längler ◽

Michael Hack

Keyword(s):

Time Dependent ◽

Operator Approach ◽

Mechanical Fatigue

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Thermo-mechanical fatigue damage behavior for Ni-based superalloy under axial-torsional loading

Materials Science and Engineering A ◽

10.1016/j.msea.2018.02.029 ◽

2018 ◽

Vol 719 ◽

pp. 61-71 ◽

Cited By ~ 12

Author(s):

Dao-Hang Li ◽

De-Guang Shang ◽

Cheng-Cheng Zhang ◽

Xiao-Dong Liu ◽

Fang-Dai Li ◽

...

Keyword(s):

Fatigue Damage ◽

Torsional Loading ◽

Damage Behavior ◽

Mechanical Fatigue

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A Fundamental Overview of Accelerated Testing Analytical Models

Journal of the IEST ◽

10.17764/jiet.41.1.3626j43p305q1978 ◽

1998 ◽

Vol 41 (1) ◽

pp. 16-20 ◽

Cited By ~ 21

Author(s):

Hank Caruso ◽

Abhijit Dasgupta

Keyword(s):

Fatigue Damage ◽

Accelerated Life Testing ◽

Analytical Models ◽

Aging Effects ◽

Chemical Aging ◽

Life Estimation ◽

Mechanical Fatigue ◽

Accelerated Life ◽

Steady State Temperature ◽

Acceleration Model

This paper describes analytical models that are commonly used for product life estimation and accelerated life testing. Model descriptions include: Miner's "Rule" for describing accumulated fatigue damage; Coffin-Manson nonlinear power law, often applied to mechanical fatigue damage; Rudra model for CFF failures; Arrhenius steady-state temperature acceleration model for estimating chemical aging effects; Peck's model for accelerated combined temperature-humidity effects; and Kemeny model for combined temperature and voltage acceleration effects. The general form of these models will be presented along with specific guidance regarding: relative strengths and appropriate applications for each model; limitations and sources of uncertainty for each model; and example values for exponents and material coefficients.

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Development of a Fatigue Damage and Lifing Assessment Method for Inconel 625 and Aluminum 6061-T6

Volume 7A: Structures and Dynamics ◽

10.1115/gt2017-63775 ◽

2017 ◽

Author(s):

Dino Celli ◽

M.-H. Herman Shen ◽

Tommy George ◽

Onome Scott-Emuakpor ◽

Casey Holycross

Keyword(s):

Fatigue Damage ◽

Strain Energy ◽

Room Temperature ◽

Assessment Method ◽

Fatigue Tests ◽

Inconel 625 ◽

Total Strain Energy ◽

Mechanical Fatigue ◽

Energy Dissipated ◽

Good Agreement

An energy based fatigue damage and lifing assessment method is developed for a high temperature material, Inconel 625, and Aluminum 6061-T6. A newly developed experimental method is used for interrogating accumulated fatigue damage and evolution for low and high cycle fatigue (LCF/HCF) at continuum scales. The proposed fatigue lifing assessment method is based on assessing the total strain energy dissipated to cause fatigue failure of a material, known as the fatigue toughness. From the fatigue toughness and experimentally determined fatigue lives at two different stress amplitudes, the cyclic parameters of the Ramberg-Osgood constitutive equation that describes the hysteresis stress-strain loop of a cycle are determined. Stress controlled mechanical fatigue tests are performed to construct room temperature stress-life (S-N) curves and to determine damage progression based on accumulated fatigue damage. The predicted fatigue life obtained from the present energy based approach is found in good agreement with experimental data.

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