1. Project “The development of the didactic potential of Cracow University of Technology in the range of modern construction” is co-financed by the European Union within the confines of the European Social Fund and realized under surveillance of Ministry of Science and Higher Education 1/71/7 M.Chrzanowski: Strength of Materials 3 SM3-02: Theoretical strength THEORETICAL STRENGTH OF SOLIDS Lennart-Jones model

2. Project “The development of the didactic potential of Cracow University of Technology in the range of modern construction” is co-financed by the European Union within the confines of the European Social Fund and realized under surveillance of Ministry of Science and Higher Education 2/72/7 M.Chrzanowski: Strength of Materials 3 SM3-02: Theoretical strength s FrFr FaFa FaFa FrFr Reactive force (repulsion)Active force (attraction) m > n (m  10, n  5) For s=s o soso FrFr FaFa FaFa FrFr

3. Project “The development of the didactic potential of Cracow University of Technology in the range of modern construction” is co-financed by the European Union within the confines of the European Social Fund and realized under surveillance of Ministry of Science and Higher Education 3/73/7 M.Chrzanowski: Strength of Materials 3 SM3-02: Theoretical strength s > s o FrFr FaFa FaFa FrFr FF soso F  0  =s-s o F s 0

4. Project “The development of the didactic potential of Cracow University of Technology in the range of modern construction” is co-financed by the European Union within the confines of the European Social Fund and realized under surveillance of Ministry of Science and Higher Education 4/74/7 M.Chrzanowski: Strength of Materials 3 SM3-02: Theoretical strength F  0 F=F R  =  R  =  R 

5. Project “The development of the didactic potential of Cracow University of Technology in the range of modern construction” is co-financed by the European Union within the confines of the European Social Fund and realized under surveillance of Ministry of Science and Higher Education 5/75/7 M.Chrzanowski: Strength of Materials 3 SM3-02: Theoretical strength m=10, n =5 =(10  1000)x(dośw F R ) Reasons of model to experiment discrepancy: 1.Very simplistic model 2.Defects of real crystal arrangement neglected (see Theory of Dislocations)

6. Project “The development of the didactic potential of Cracow University of Technology in the range of modern construction” is co-financed by the European Union within the confines of the European Social Fund and realized under surveillance of Ministry of Science and Higher Education 6/76/7 M.Chrzanowski: Strength of Materials 3 SM3-02: Theoretical strength Further idealisation  =  R F 0  F=F R Experimental value:

7. Project “The development of the didactic potential of Cracow University of Technology in the range of modern construction” is co-financed by the European Union within the confines of the European Social Fund and realized under surveillance of Ministry of Science and Higher Education 7/77/7 M.Chrzanowski: Strength of Materials 3 SM3-02: Theoretical strength  = 0,25 0   = 0,50 Energy consumed Energy density per unit volume to cause failure Further considerations in Fracture Mechanics