The deformation kinetics theory of the stress dependence of plastic deformation

Krausz, A. S.; Krausz, K.

doi:10.1016/0956-7151(94)90288-7

Cited by 4 publications

(3 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Based on the above scenario for the length change of the two dashpots at the loading stages, spring constants,

K_{normalv, normalS}

and

K_{normalv, normalL}

, can be determined in the following manner. For the S‐branch, since the rate of length increase of its dashpot,

{\dot{δ}}_{normald, normalS}

, has reached the constant crosshead speed of 5 mm/min (0.0833 mm/s) at the end of the loading stage, based on the definition of reference deformation rate

((), {\overset{δ}{true}}_{0, S})

in the Eyring's model 22 :

{\dot{δ}}_{0, normalS} goodbreak= σ_{0, normalS} / ((), τ_{normalv, normalS} K_{normalv, normalS}) .

…”

Section: Discussionmentioning

confidence: 99%

Analysis of time‐dependent mechanical behavior of polyethylene

Jar

2024

SPE Polymers

View full text Add to dashboard Cite

New data analysis based on a spring‐dashpot model is developed to provide very close simulation of stress variation in polyethylene (PE) when subjected to a multi‐relaxation (MR) test. The model consists of a quasi‐static branch and two (long‐ and short‐term) viscous branches. The study shows that viscous stresses applied to the two dashpots and the model parameters can be quantified as functions of displacement (stroke) by simulating closely the stress variation in relaxation. Using these parameters, influences of stress triaxiality and material grade on PE's stress response at relaxation stages are examined, and along with experimental data at the loading stages, spring constants in the two viscous branches are determined. The results indicate that among three PE grades, spring constants and their trend of variation are similar in the long‐term viscous branch, but not in the short‐term counterpart. The results also show that by decreasing specimen gauge length 10 times to increase stress triaxiality, spring constants in the two viscous branches become closer to each other. The work concludes that the new data analysis can determine all parameters in the model, which can then be considered to quantify the role of the viscous stress response for PE's load‐carrying performance.Highlights Use a simple model to simulate complex, multiple relaxation behaviors of PE. Determine all model parameter values to characterize PE's relaxation behavior. Illustrate the effect of stress triaxiality on PE's viscous stress response. Show the similarity and difference of the viscous stress response among 3 PEs.

show abstract

“…Based on the above scenario for the length change of the two dashpots at the loading stages, spring constants,

K_{normalv, normalS}

and

K_{normalv, normalL}

, can be determined in the following manner. For the S‐branch, since the rate of length increase of its dashpot,

{\dot{δ}}_{normald, normalS}

, has reached the constant crosshead speed of 5 mm/min (0.0833 mm/s) at the end of the loading stage, based on the definition of reference deformation rate

((), {\overset{δ}{true}}_{0, S})

in the Eyring's model 22 :

{\dot{δ}}_{0, normalS} goodbreak= σ_{0, normalS} / ((), τ_{normalv, normalS} K_{normalv, normalS}) .

…”

Section: Discussionmentioning

confidence: 99%

Analysis of time‐dependent mechanical behavior of polyethylene

Jar

2024

SPE Polymers

View full text Add to dashboard Cite

show abstract

“…Similar to the kinetics equation, the state equation describes the continuous variation in microstructure during the thermally activated process in terms of plastic deformation [60]. In the state equation, the work done by applied stress, ), is replaced by the product of activation volume, , and effective stress, , which is equal to the difference between applied stress, , and internal stress, [61]. Then the strain rate is given by:…”

mentioning

confidence: 99%

“…According to the deformation theory given by Kraus [61], the temperature-dependent strain rate can be expressed as:…”

mentioning

confidence: 99%

Temperature-Dependent Fracture Toughness Evaluation of WC-10Co4Cr Coating/1018 Low Carbon Steel Substrate System

Gu¹

View full text Add to dashboard Cite

The temperature-dependent fracture toughness of WC-10Co4Cr coating/1018 low carbon steel substrate, which is a brittle coating/ductile substrate system, is evaluated at microscopic level with two types of models developed in terms of the Arrhenius-type equation and rate controlling theory, utilizing indentation test data, in this research. One is based on the crystal structures of individual phases in the composite coating, the other considers the microcrack formation in the coating/substrate system under indentation loading. Using the crystal-structure-based model, the slip systems of the hard hexagonal -WC phase and soft FCC -Co phase are analyzed. The fracture toughness of the two-phase composite coating is obtained by integrating the fracture toughness of -WC phase and -Co phase using either the basic mixture method or the unconstrained mixture method. The estimated fracture toughness using this type of model is independent of indentation load. For the microcrack-formation-based models, numerous microcracks are generated from each corner of indentation impression and merge together to form radial cracks due to the tension of residual stresses in the coating/substrate system under indentation, and the radial cracks extend along the indentation diagonals under the residual stresses. The dislocation movement of atoms can be associated with the microcrack formation in the indentation process thus the fracture toughness of the composite coating/substrate system is evaluated. Due to the effect of ductile substrate on brittle coating, two approaches are used to investigate the indentation pressure imposed on the system, one expresses the indentation pressure as the applied load ii divided by the projected area of indentation impression, the other is based on the composite hardness of the coating/substrate system, but both approaches take the substrate effect into the fracture toughness evaluation. The estimated fracture toughness of WC-10Co4Cr coating/1018 low carbon steel substrate system at high temperatures shows that the crystal-structure-based model and microcrack-formation-based models are in good agreement. The fracture toughness of WC-10Co4Cr coating/1018 low carbon steel substrate system remains unchanged until the temperature reaches a critical value, 200 for crystal-structure-based model, 150 for microcrack-formation-based models. It then increases rapidly in an exponential manner. The room-temperature fracture toughness of the coating/substrate system obtained from all models is about 2.1 ⁄ , the fracture toughness at 1000 ranges from 8.5669 ⁄ to 11.2399 ⁄ using different models and under different indentation loads. iii Acknowledgements I owe my sincere gratitude to my supervisors, Professor Rong Liu, for her constant support and guidance during my research and study at Carleton University. Her expert knowledge and endless patience are invaluable and indispensible for me to finish this thesis.

show abstract

The Constitutive Law of Deformation Kinetics

Krausz

1996

Unified Constitutive Laws of Plastic Deformation

View full text Add to dashboard Cite

The deformation kinetics theory of the stress dependence of plastic deformation

Cited by 4 publications

References 11 publications

Analysis of time‐dependent mechanical behavior of polyethylene

Analysis of time‐dependent mechanical behavior of polyethylene

Temperature-Dependent Fracture Toughness Evaluation of WC-10Co4Cr Coating/1018 Low Carbon Steel Substrate System

The Constitutive Law of Deformation Kinetics

Contact Info

Product

Resources

About