THEORETICAL STRENGTH OF SOLIDS

1
THEORETICAL STRENGTH OF SOLIDS

• Lennart-Jones model

2
Fr
Fa
Fa
Fr
m gt n
(m?10, n ? 5)
Reactive force (repulsion)
Active force (attraction)
For sso
Fr
Fa
Fa
Fr
3
Fr
Fa
Fa
Fr
F
F
?s-so
so
4
FFR
?
? ?R
? ?R
5
m10, n 5
(10?1000)x(dosw FR)

• Reasons of model to experiment discrepancy
• Very simplistic model
• Defects of real crystal arrangement neglected
  (see Theory of Dislocations)

6
Further idealisation
FFR
? ?R
Experimental value
7
Energy consumed
Energy density per unit volume to cause failure
Further considerations in Fracture Mechanics