1. Strain rate sensitivity to crack growth  (9/30/01)

   Subroutine for user defined materials
   ----------------------
      crack-growth.f             -   constitutive model for crack growth  (umshl53.f):
      crack-set.f                -   material setup routine (umset53.f)

   DYNA3D Input files:
   ----------------------
      one-strain-1over10         -   strain rate = 0.1 /sec
      one-strain-20              -   strain rate = 20  /sec
      one-strain-50              -   strain rate = 50  /sec

   Plot files:
   ----------------------
      one-strain-cracksize.jnb   -    Evolutions of crack size vs. strain 
      one-strain-ss.jnb          -    Stress-strain responses    
   

2. Damage models (9/30/01)

   Subroutine for user defined materials (umshl53.f):
   ----------------------
      crack-nucleation.f           -   constitutive model for crack nucleation
      crack-growth.f               -   constitutive model for crack growth   
      crack-nucleation-growth.f    -   constitutive model for crack nucleation 
                                       and growth   
   DYNA3D Input files:
   ----------------------
      one-comp-nucleation          -   crack nucleation
      one-comp-growth              -   crack growth
      one-comp-nucleation-growth   -   crack nucleation and growth

   Plot files:
   ----------------------
      one-comp-nucleation.jnb      -   evolutions of number of cracks vs. strain 
      one-comp-growth.jnb          -   evolutions of crack size vs. strain    
      one-comp-ss.jnb              -   stress-strain responses 

3. Drop tower test

   Subroutine for user defined materials (umshl53.f):
   ----------------------
      drop-fail-stress-driven.f (= crack-growth.f)  -  constitutive model with stress 
                                                       driven failure criteria
      drop-fail-strain-driven.f                     -  constitutive model with strain

   Subroutine for user defined failure (umfail.f):
   ----------------------
      fail.f                    -  subroutine for material failure
      
   DYNA3D Input files:
   ----------------------
      drop-input              

   Plot files:
   ----------------------
      defx.jpg                  -   Sequence of deformed shape (x=1,2,3,4) 
      drop-stress.jpg           -   P-D curves based on stress driven failure criteria
                                    (Tube crushes when effective stress reaches 
                                     critical stress point.)
      drop-strain.jpg           -   P-D curves based on strain driven failure criteria
                                    (Tube starts crushing when crack size reaches 
                                     critical size followed by load oscillations 
                                     associated with progressive crushing.)
      drop-stress-strain.jpg    -   drop-stress.jpg + drop-strain.jpg
                                    (Tube absorbs more energy when using the strain 
                                     driven failure criteria.)

4. Micromechanics based damage model (9/30/01)

   -  developed micromechanics based damage models to model fiber debonding
   
   Subroutine for user defined materials (umshl53.f):
   ----------------------
      mm-fiber-debond.f         -   constitutive model for fiber debonding (umshl53.f)
      mm-set.f                  -   material setup routine (umset53.f)

5. Cohesive element model for modeling interfaces and delamination  (9/30/01)

   uel03062000.f