Sectorial Areas, Static Moments, and Tangential Stresses for an Open Thin-Walled Section

Aim: To check the accuracy of the determination of sectorial areas ω, a sectorial static moment Sω, and tangential stresses τω, caused by constrained torsion for an open thin-walled section.

Name of a file with the initial data: Prokic_open.tns

Formulation: Check the accuracy of the calculation of the sectorial areas, static moments, and tangential stresses for an open thin-walled section.

References: Prokić A. Computer program for determination of geometrical properties of thin-walled beams with open-closed section // Computers and Structures, Vol. 74 (2000). – pp. 705 – 715.

Initial data:


Open thin-walled section with sizes, cm

Results from the source:

Sectorial area diagram ω, cm2

 

Diagram of tangential stresses related to the constrained torque, τω/Mω×107, 1/cm3

 

Results obtained in Tonus:


Numbering of vertices and strips, position of the mass center and shear center

 


Sectorial area diagram ω, cm2

 


Sectorial static moment diagram Sω, cm4

 


Diagram of the tangential stress module τω for the value of the constrained torque Mω = 107, kNcm

 

Comparison of results:

Element number

Vertex number

Sectorial static moment, cm4

Tangential stress, kN/cm2

(at Mω = 107, kNcm)

Source*

TONUS

Deviation,

%

Source

TONUS

Deviation,

%

1

1

32126

32140

0,04

1735

1736

0,06

1

2

0

0

0

0

0

0

2

1

32126

32140

0,04

3470

3472

0,06

2

8

30580

30585

0,02

3303

3304

0,06

3

8

30580

30585

0,02

2202

2202

0

3

4

7999

7985

0,18

576

575

0,17

4

4

6013

6019

0,1

433

432

0,23

4

5

0

0

0

0

0

0

5

4

14008

14004

0,03

1513

1513

0

5

3

15498

15498

0

1674

1674

0

6

6

0

0

0

0

0

0

6

3

25423

25443

0,08

1373

1374

0,07

7

3

9943

9945

0,02

537

537

0

7

7

0

0

0

0

0

0

Note:

*The value of the static sectorial moment Sω was calculated using the value τω/Mω, obtained from the source as (Iω = 92582119 cm6): Sω.=  τωIωt / Mω.

 

Vertex number

Sectorial area, cm2

Source

TONUS

Deviation, %

1

707

707

0

2

1436

1436

0

3

-258

-258

0

4

308

308

0

5

494

494

0

6

-1438

-1438

0

7

921

921

0

8

-810

-810

0