scholarly journals Discussion: “Analysis of Creep in Rotating Disks Based on the Tresca Criterion and Associated Flow Rule” (Wahl, A. M., 1956, ASME J. Appl. Mech., 23, pp. 231–238)

1957 ◽  
Vol 24 (1) ◽  
pp. 155
Author(s):  
P. G. Hodge
Keyword(s):  
Flow Rule ◽  
Rotating Disks ◽  
Tresca Criterion ◽  
Associated Flow Rule

Analysis of Creep in Rotating Disks Based on the Tresca Criterion and Associated Flow Rule

1956 ◽  
Vol 23 (2) ◽  
pp. 231-238
Author(s):  
A. M. Wahl
Keyword(s):  
Steady State ◽  
Creep Rate ◽  
Constant Temperature ◽  
Variable Thickness ◽  
Constant Thickness ◽  
Flow Rule ◽  
Test Results ◽  
Rotating Disks ◽  
Tresca Criterion ◽  
Associated Flow Rule

Abstract An analysis of creep deformations in rotating disks based on the Tresca criterion and the associated flow rule is presented. Assuming steady-state creep conditions and a creep rate equal to a function of stress times a function of time, the method is applied to the following cases: (a) Disk with constant thickness and constant temperature, (b) disk with variable thickness and constant temperature, and (c) disk with variable thickness and variable temperature. In many cases, the equations can be expressed in closed form. Comparison is made with test results on rotating disks at elevated temperature as reported in a previous paper. Based on certain stress-creep-rate relations, the method is also applied to the problem of calculating the transient change in stress when the stress distribution changes from an initial to a steady-state condition during the starting period. It is suggested that the simplification effected by the use of these methods may be of value for design purposes pending the development of more accurate methods based on test results.

Gradient of Soil Constitutive Model

2010 ◽  
Vol 168-170 ◽  
pp. 1126-1129
Author(s):  
Wen Xu Ma ◽  
Ying Guang Fang
Keyword(s):  
Plastic Strain ◽  
Strain Gradient ◽  
Soil Analysis ◽  
Natural Material ◽  
Flow Rule ◽  
The Finite Element Method ◽  
Gradient Effect ◽  
Non Local ◽  
Associated Flow Rule ◽  
Plastic Strain Gradient

For the soil is a very complex natural material, significant strain gradient effect exist in soil analysis. Based on the "gradient" phenomenon, we add the plastic strain gradient hardening item into the traditional Cambridge yield surface. By using the consistency conditions and associated flow rule, we get the explicit expression of plastic strain gradient stiffness matrix. And the finite element method of plastic strain gradient is also shown in this article. Plastic strain gradient is actually a phenomenological non-local model containing microstructure information of the material. It may overcome the difficulties in simulating the gradient phenomenon by traditional mechanical model.

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