Describir: Plastic analysis of structures ..

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