Equalization Charging Technology for Battery Pack - Study Based on State Variable Theory Approach

2021 ◽  
Vol 56 (5) ◽  
pp. 766-773
Author(s):  
Toshiyuki Sakamoto
Keyword(s):  
Battery Pack ◽  
Theory Approach ◽  
Variable Theory ◽  
State Variable

Mechanisms-based creep constitutive equations for an aluminium alloy

1994 ◽  
Vol 29 (4) ◽  
pp. 309-316 ◽  
Author(s):  
Z L Kowalewski ◽  
D R Hayhurst ◽  
B F Dyson
Keyword(s):  
Aluminium Alloy ◽  
Constitutive Equations ◽  
Good Description ◽  
Creep Behaviour ◽  
Linear Equations ◽  
Damage Mechanism ◽  
Optimization Techniques ◽  
Variable Theory ◽  
Strongly Coupled ◽  
State Variable

A number of mechanisms-based constitutive equations were assessed in an effort to describe the creep behaviour of an aluminium alloy at 150°C. It was found that a sinh function of stress, rather than the usually used power law, is best able to describe the strain rate and rupture behaviour over the narrow stress range analysed. A single state variable theory which represents a dominant damage mechanism is not capable of predicting the shape of the tertiary curve; however, a two state variable theory which represents two mechanisms provides a good description. The two relevant mechanisms identified are creep-constrained cavitation and ageing of the particulate microstructure. The non-linear equations which describe both these physical mechanisms are complex and strongly coupled. This makes it difficult to determine the constants in the constitutive equations from experimental data. The paper reports the development of automated numerical optimization techniques which overcome these difficulties.

A State Variable Interpretation of Some Rate-Dependent Inelastic Properties of Steel

1978 ◽  
Vol 100 (4) ◽  
pp. 395-401 ◽  
Author(s):  
B. Larsson ◽  
B. Stora˚kers
Keyword(s):  
Stainless Steel ◽  
Elevated Temperature ◽  
Constitutive Equation ◽  
Physical Theory ◽  
Creep Tests ◽  
Variable Theory ◽  
One Dimensional ◽  
State Variable ◽  
Rate Dependent ◽  
Stress States

Based on a state variable theory proposed by Onat some discriminating creep tests of stainless steel have been designed and carried out at elevated temperature conditions. Quantitative correlations of the results are sought with predictions from a physical theory for recovery creep proposed by Lagneborg. The findings are utilized to interpret the behavior of creeping members when subjected to a rapid increase in the rate of straining. Different approaches toward generalization of physical one-dimensional creep laws to multiaxial stress states are discussed. A tentative constitutive equation applicable to the solution of general boundary value problems is proposed.

A continuum state variable theory to model the size-dependent surface energy of nanostructures

2015 ◽  
Vol 17 (38) ◽  
pp. 25494-25498 ◽  
Author(s):  
Mostafa Jamshidian ◽  
Prakash Thamburaja ◽  
Timon Rabczuk
Keyword(s):  
Free Energy ◽  
Energy Density ◽  
Surface Energy ◽  
Surface Free Energy ◽  
Free Energy Density ◽  
Continuum State ◽  
Variable Theory ◽  
Size Dependent ◽  
State Variable ◽  
Excess Surface

We propose a continuum-based state variable theory to quantify the excess surface free energy density throughout a nanostructure.

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