Call number:
ZSP-201-83/33
In:
CRREL Report, 83-33
Description / Table of Contents:
A thermodynamic model has been developed that for the first time describes the entire creep process, including primary, secondary, and tertiary creep, and failure for both constant stress (CSR) tests (σ= const.) and constant strain rate (CSR) tests (ϵ = const.), in the form of a unified constitutive equation and unified failure criteria. Deformation and failure areconsidered as a single thermoactivated process in which the dominant role belongs to the change of entropy. Failure occurs when the entropy change is zero. At that moment the strain rates in CS tests reach the minima and stress in CSR tests reaches the maximum (peak) values. Families of creep (ϵ vs τ) and stress-strain (σ vs ϵ) curves, obtained from uni-axial compression CS and CSR tests of frozen soil, respectively (both presented in dimensionless coordinates), are plotted as straight lines and are superposed, confirming the unity of the deformation and failure process and the validity of the model. A method is developed for determining the parameters of the model, so that creep deformation and the stress-strain relationship of ductile materials such as soils can be predicted based upon information obtained from either type of test.
Type of Medium:
Series available for loan
Pages:
v, 25 Seiten
,
Illustrationen
Series Statement:
CRREL Report 83-33
URL:
https://apps.dtic.mil/docs/citations/ADA139883
URL:
https://hdl.handle.net/11681/9285
Language:
English
Note:
CONTENTS
Abstract
Nomenclature
Introduction
Principal relationships
Constitutive equation
Failure criteria
Secondary creep: Flow equations
Creep at constant stress (σ = Const.)
Creep model
Creep strain (σ = Const.)
Creep at constant strain rate (ϵ = Const.)
Stress-strain relationship
Stress/strain/strain rate at failure
Test data
Preliminary analysis
Constant stress tests (σ = Const.)
Constant strain rate tests (ϵ = Const.)
The principle of superposition
Thermodynamic equation of creep
Conclusions
Literature cited
Location:
AWI Archive
Branch Library:
AWI Library
