Predicting fatigue resistance of nano-twinned materials: Part I – Role of cyclic slip irreversibility and Peierls stress

2014 ◽  
Vol 68 ◽  
pp. 277-291 ◽  
Author(s):  
Piyas B. Chowdhury ◽  
Huseyin Sehitoglu ◽  
Richard G. Rateick
Keyword(s):  
Fatigue Resistance ◽  
Peierls Stress ◽  
Cyclic Slip

The Effect of Electric Charges Formed during Repeated Deformations on the Fatigue Resistance of Vulcanizates

1960 ◽  
Vol 33 (4) ◽  
pp. 970-970 ◽  
Author(s):  
B. A. Dogadkin ◽  
V. E. Gul ◽  
N. A. Morozova
Keyword(s):  
Zinc Oxide ◽  
Oleic Acid ◽  
Fatigue Resistance ◽  
Acetylene Black ◽  
Black Oil

Abstract Electroelastic and triboelastic effects result in the formation of electric charges on articles made from polymers undergoing deformation. It was of interest to determine the effect of the charges formed during deformation on the fatigue resistance of vulcanizates. No convincing experiments clearly demonstrating the role of electric charges arising during friction or deformation had been carried out previously. Vulcanizates containing different amounts of acetylene black were tested in a machine in which cylindrical specimens with thickened ends were subjected to repeated bending at 1300 cycles/minute. The stocks had the following composition (in parts by weight) : SKS-30A 100, sulfur 2, technical stearin 2, Rubrax 5, black oil 4, MBTS 0.6, diphenylguanidine 0.8, zinc oxide 5, oleic acid 1. Increasing amounts of acetylene black were added to this composition: 6, 12, 18, 20, 22, 30, 40 and 75 wt. parts per 100 wt. parts of rubber.

The Fatigue Properties of Duplex Stainless Steels: Role of Microstructure

2008 ◽  
Vol 378-379 ◽  
pp. 101-114 ◽  
Author(s):  
Jean Bernard Vogt
Keyword(s):  
Fatigue Resistance ◽  
Stainless Steels ◽  
Load Transfer ◽  
Volume Fraction ◽  
Low Cycle Fatigue ◽  
Fatigue Behaviour ◽  
Cyclic Softening ◽  
Duplex Stainless Steels ◽  
Fatigue Properties

The paper analyzes the role of microstructure on the low cycle fatigue behaviour of duplex stainless steels. The alloys are investigated in their as received condition and after ageing at 475°C. The fatigue resistance and the cyclic accommodation of these DSS are strongly controlled by the volume fraction of α and γ "phases which is related to the chemical composition in particular nitrogen. It is shown that DSS with a high fraction of austenite present a good combination of fatigue resistance and cyclic softening especially in the aged condition. The mutual interaction between ferrite and austenite referred to load transfer is beneficial for increasing the fatigue resistance. Alloying with nitrogen appears to be a promising way to master an optimised microstructure leading to high mechanical resistant DSS.

scholarly journals Assessment of the role of cross section on fatigue resistance of rotary files when used in reciprocation

2016 ◽  
Vol 10 (04) ◽  
pp. 541-545 ◽  
Author(s):  
Vadhana Sekar ◽  
Ranjith Kumar ◽  
Suresh Nandini ◽  
Suma Ballal ◽  
Natanasabapathy Velmurugan
Keyword(s):  
Cross Section ◽  
Fatigue Resistance ◽  
Fatigue Testing ◽  
Dynamic Testing ◽  
Cyclic Fatigue ◽  
Reciprocating Motion ◽  
Continuous Rotation ◽  
Significant Difference ◽  
Post Hoc

ABSTRACT Objective: The purpose of this study was to assess the role of cross section on cyclic fatigue resistance of One Shape, Revo-S SU, and Mtwo rotary files in continuous rotation and reciprocating motion in dynamic testing model. Materials and Methods: A total of 90 new rotary One Shape, Revo-S SU, and Mtwo files (ISO size 25, taper 0.06, length 25 mm) were subjected to continuous rotation or reciprocating motion. A cyclic fatigue testing device was fabricated with 60° angle of curvature and 5 mm radius. The dynamic testing of these files was performed using an electric motor which permitted the reproduction of pecking motion. All instruments were rotated or reciprocated until fracture occurred. The time taken for each instrument to fracture was recorded. All the fractured files were analyzed under a scanning electron microscope (SEM) to detect the mode of fracture. Statistical analysis was performed using one-way ANOVA, followed by Tukey's honestly significant difference post hoc test. Results: The time taken for instruments in reciprocating motion to fail under cyclic loading was significantly longer when compared with groups in continuous rotary motion. There was a statistically significant difference between Mtwo rotary and the other two groups in both continuous and reciprocating motion. One Shape rotary files recorded significantly longer duration to fracture resistance when compared with Revo-S SU files in both continuous and reciprocating motion. SEM observations showed that the instruments of all groups had undergone a ductile mode of fracture. Conclusion: Reciprocating motion improved the cyclic fatigue resistance of all tested groups.

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