scholarly journals Experimental characterization of a CuAg alloy for thermo-mechanical applications: non-linear plasticity models and low-cycle fatigue curves

2018 ◽  
Vol 213 ◽  
pp. 743-753
Author(s):  
D. Benasciutti ◽  
F. De Bona ◽  
L. Moro ◽  
J. Srnec Novak
Keyword(s):  
Low Cycle Fatigue ◽  
Experimental Characterization ◽  
Cycle Fatigue ◽  
Non Linear

Modeling of Internal Damage Evolution During Actuation Fatigue in Shape Memory Alloys

2018 ◽  
Author(s):  
Francis R. Phillips ◽  
Daniel Martin ◽  
Dimitris C. Lagoudas ◽  
Robert W. Wheeler
Keyword(s):  
Phase Transformation ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Damage Evolution ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Internal Damage ◽  
Functional Fatigue ◽  
Non Linear

Shape memory alloys (SMAs) are unique materials capable of undergoing a thermo-mechanically induced, reversible, crystallographic phase transformation. As SMAs are utilized across a variety of applications, it is necessary to understand the internal changes that occur throughout the lifetime of SMA components. One of the key limitations to the lifetime of a SMA component is the response of SMAs to fatigue. SMAs are subject to two kinds of fatigue, namely structural fatigue due to cyclic mechanical loading which is similar to high cycle fatigue, and functional fatigue due to cyclic phase transformation which typical is limited to the low cycle fatigue regime. In cases where functional fatigue is due to thermally induced phase transformation in contrast to being mechanically induced, this form of fatigue can be further defined as actuation fatigue. Utilizing X-ray computed microtomography, it is shown that during actuation fatigue, internal damage such as cracks or voids, evolves in a non-linear manner. A function is generated to capture this non-linear internal damage evolution and introduced into a SMA constitutive model. Finally, it is shown how the modified SMA constitutive model responds and the ability of the model to predict actuation fatigue lifetime is demonstrated.

Damage in Adhesive Joints During Low Cycle Fatigue

2010 ◽  
Author(s):  
Iva´n C. Ca´bulo-Pe´rez ◽  
Juan P. Casas-Rodri´guez
Keyword(s):  
Plastic Strain ◽  
Low Cycle Fatigue ◽  
Stress Test ◽  
Damage Model ◽  
Fatigue Tests ◽  
Constant Stress ◽  
Cycle Fatigue ◽  
Damage Behavior ◽  
Non Linear ◽  
Compressive Loads

The objective of this research is to study the damage behavior of bulk adhesive and single lap joint (SLJ) specimens during low cycle fatigue (LCF). Fatigue tests under constant stress amplitude were done and strain response was measured through cycles to failure using the bulk adhesive and SLJ data. A non linear damage model was used to fit experimental results. Identification of the damage parameters for bulk adhesive was obtained from the damage against accumulated plastic strain plot. It is shown that the plastic strain can be obtained from the constant stress test if the instantaneous elastic modulus, i.e. modulus affected by damage, is evaluated for each cycle. On the other hand, damage in SLJ was seen mainly in the adhesive for itself — no substrate failure — this fact is used to propose that fatigue response in the joint is due to continuum damage accumulation in the adhesive as the number of cycles increases. Damage behavior under compressive loads was not taken into account but good correlation of numerical and experimental data was obtained. It was found that damage evolution behaves in a non linear manner as the plastic deformation grows for each cycle: on fatigue onset an accelerated damage grow is observed, then a proportional evolution, and finally a rapid failure occurs; this characteristics were seen in both the SLJ and bulk adhesive specimen. So far, this research takes the damage model found in a standard adhesive specimen and assumes it is accurate enough to represent the damage behavior of the SLJ configuration.

scholarly journals High temperature low cycle fatigue characterization of equiaxed MAR-M-247

2019 ◽  
Vol 123 ◽  
pp. 225-237
Author(s):  
G. Maggiani ◽  
M.J. Roy ◽  
S. Colantoni ◽  
P.J. Withers ◽  
S. Stramare ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue

Characterization of low cycle fatigue damage in 9Cr–1Mo ferritic steel using X-ray diffraction technique

1999 ◽  
Vol 76 (5) ◽  
pp. 275-281 ◽  
Author(s):  
Sanjay Rai ◽  
B.K Choudhary ◽  
T Jayakumar ◽  
K.Bhanu Sankara Rao ◽  
Baldev Raj
Keyword(s):  
Fatigue Damage ◽  
Ferritic Steel ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
X Ray Diffraction ◽  
X Ray
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