Constitutive relations and classical plasticity Flashcards
What does a tensile test provide?
An experiment approach to studying basic material behaviour
What assumptions are made during a tensile test?
Loading is pure axial and the deformation takes place uniformly, both along the length and cross section of the specimen
How is a tensile test carried out?
By moving one end of the specimen at constant speed, while holding the other end fixed
What are the primary variables recorded during a tensile test?
Load (F) and extension (L)
What is required to determine true stress?
Knowledge of the instantaneous area at all times during deformation
What determines plastic deformation?
When stresses exceed the yield stress
What determines elastic behaviour?
Total strain is entirely recoverable - total strain is equal to the elastic strain
What is plastic strain?
A function of the stress on unloading
In the stress tensor matrix, which components are considered to represent normal stress?
Sigma_11, Sigma_22, Sigma_33
What components are present in the hydrostatic stress tensor?
Pure tensile or compressive stress
What components are present in the deviatoric stress tensor?
Shear stresses of the total stress state
What physical change is caused by hydrostatic strain?
Volume change
What physical change is caused by deviatoric strain?
Change in shape
What are the principle stresses?
Where the stress tensor has zero shear components and non-zero normal stresses
How do you define the stress state?
By using all components of the stress tensor
