Text this: Formulation of constitutive relations based on indentation test

__    __     ___      _  _    __   __   __   _   
\ \\ / //   / _ \\   | \| ||  \ \\/ // | || | || 
 \ \/ //   | / \ ||  |  ' ||   \ ` //  | '--' || 
  \  //    | \_/ ||  | .  ||    | ||   | .--. || 
   \//      \___//   |_|\_||    |_||   |_|| |_|| 
    `       `---`    `-` -`     `-`'   `-`  `-`