# Part I. Theory report for CREEP-PLAST computer program: analysis of two- dimensional problems under simultaneous creep and plasticity

## Abstract

>Solution of the combined creep and plasticity problem is considered. Both creep theories, the equation-of-state and memory theories, are used within the framework of the finite-element computatioral method. Because of the limited creep data, which is available only for single-step simple extension experiments, the integral expansion in the memory theory formulation is limited to one nonlinear superposition integral. However, instead of using direct superposition as proposed earlier, the kernel function was derived as an integral transformation that reduced the time--temperature- stress relationship to a single quantity. The equationof-state formulation is based on the monotoric strain-hardening rule app1ied to the primary creep componert only. The uniaxial stress- strain law is first discussed with emphasis on the memory theory. Then the incremental stress- strain relations for the combined creep and plasticity problem are derived for both creep theories. The time--temperature- stress transformation is derived for a particular class of material that exhibits well- defined primary and secondary creep parts such as stainless steel. The properties of the resulting stress- strain integral are discussed in relation to the direct-superposition method. Finally, example analyses are given. (auth)

- Authors:

- Publication Date:

- Research Org.:
- General Electric Co., San Jose, Calif. (USA). Nuclear Fuels Dept.

- Sponsoring Org.:
- Union Carbide Corporation Nuclear Division

- OSTI Identifier:
- 4377082

- Report Number(s):
- GEAP-10546

3511

- NSA Number:
- NSA-29-012417

- DOE Contract Number:
- W-7405-ENG-26

- Resource Type:
- Technical Report

- Resource Relation:
- Other Information: Orig. Receipt Date: 30-JUN-74

- Country of Publication:
- United States

- Language:
- English

- Subject:
- N80600* -Mathematics &; Computers; N50000 -Metals, Ceramics, &; Other Materials; *COMPUTER CODES- C CODES; *CREEP- TWO-DIMENSIONAL CALCULATIONS; *PLASTICITY- TWO-DIMENSIONAL CALCULATIONS; EQUATIONS OF STATE; FINITE ELEMENT METHOD; METALS; STAINLESS STEELS; STRAINS; STRESSES

### Citation Formats

```
Rashid, Y. R.
```*Part I. Theory report for CREEP-PLAST computer program: analysis of two- dimensional problems under simultaneous creep and plasticity*. United States: N. p., 1972.
Web. doi:10.2172/4377082.

```
Rashid, Y. R.
```*Part I. Theory report for CREEP-PLAST computer program: analysis of two- dimensional problems under simultaneous creep and plasticity*. United States. doi:10.2172/4377082.

```
Rashid, Y. R. Sat .
"Part I. Theory report for CREEP-PLAST computer program: analysis of two- dimensional problems under simultaneous creep and plasticity". United States.
doi:10.2172/4377082. https://www.osti.gov/servlets/purl/4377082.
```

```
@article{osti_4377082,
```

title = {Part I. Theory report for CREEP-PLAST computer program: analysis of two- dimensional problems under simultaneous creep and plasticity},

author = {Rashid, Y. R.},

abstractNote = {>Solution of the combined creep and plasticity problem is considered. Both creep theories, the equation-of-state and memory theories, are used within the framework of the finite-element computatioral method. Because of the limited creep data, which is available only for single-step simple extension experiments, the integral expansion in the memory theory formulation is limited to one nonlinear superposition integral. However, instead of using direct superposition as proposed earlier, the kernel function was derived as an integral transformation that reduced the time--temperature- stress relationship to a single quantity. The equationof-state formulation is based on the monotoric strain-hardening rule app1ied to the primary creep componert only. The uniaxial stress- strain law is first discussed with emphasis on the memory theory. Then the incremental stress- strain relations for the combined creep and plasticity problem are derived for both creep theories. The time--temperature- stress transformation is derived for a particular class of material that exhibits well- defined primary and secondary creep parts such as stainless steel. The properties of the resulting stress- strain integral are discussed in relation to the direct-superposition method. Finally, example analyses are given. (auth)},

doi = {10.2172/4377082},

journal = {},

number = ,

volume = ,

place = {United States},

year = {Sat Jan 01 00:00:00 EST 1972},

month = {Sat Jan 01 00:00:00 EST 1972}

}