Issue 75

V. Landersheim et alii, Fracture and Structural Integrity, 75 (2026) 297-314; DOI: 10.3221/IGF-ESIS.75.21





1 1 1 k k k         sa s fts



k

1/

(1)

tot

Firstly, there is the stiffness sa k of the spring arm itself, which is subjected to a combined torsional and bending load. Its connection via the spacers to inner ring of the device forms an elastic clamping of the spring arm with the stiffness s k . Finally, the other force-transmitting components in the structure also have a finite stiffness denoted by fts k . The stiffness of the spring arm sa k can be described using the equations of mechanics for the elastic deformation of curved beams[21], assuming an ideal rigid clamping on one end of the curved beam, and only a translational degree of freedom in the axial direction on the other end, see Fig. 12.

Figure 12: Idealised curved bending arm.

This algebraic description is given in Eqn. 2.

      

      

     

      

     

      

A A

A A

A A

A A





2 4

2 4

1

1

2 A A

2

3

A

R A  

5

5

5

6

5

2  





A A 

k

A

1/

(2)

sa

1

2

3

EI

A

  

6 4 A A A 

  

  

A A

5

5





6 4

1

1

 

2

2

A

A

5

5

The following abbreviations are used in Eqn. 2:       1 sin 1 cos A       





     cos

  





A

sin

2





        sin

A

A

3

2

1 2

    cos



    



 

A

1 sin

4

  5 A sin   

305