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

Aim: To check the accuracy of the determination of sectorial areas ω, static moments with respect to the principal axes of inertia of the section Su, Sv, a sectorial static moment Sω, tangential stresses τu, τv, caused by shear forces, and tangential stresses τω, caused by constrained torsion for an open-closed thin-walled section.

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

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

 


Diagram of tangential stresses related to the shear force,  τu/Qu×105, 1/cm2

 

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

 


Static moment diagram Sv, cm3

 


Diagram of the tangential stress module τu for the value of the shear force Qu = 105, kN

 

 

Comparison of results:

Element number

Vertex number

Sectorial static moment Sω, cm4

Static moment Sv, cm3

Source*

TONUS

Deviation,

%

Source**

TONUS

Deviation,

%

1

1

0

0

0

0

0

0

1

2

87776

87892

0,13

3643

3634

0,25

2

2

65181

65296

0,18

740

741

0,14

2

3

63932

64036

0,16

2903

2899

0,14

3

3

67055

67159

0,16

1812

1817

0,28

6

7

26114

26164

0,19

3595

3606

0,3

6

8

26489

26517

0,11

10

7

8

44606

44666

0,13

3816

3819

0,08

9

2

22595

22595

0

4373

4369

0,09

9

7

26135

26164

0,11

3606

3606

0

10

3

3176

3177

0,03

4715

4716

0,02

10

8

18117

18149

0,15

4031

4033

0,05

Notes:

* The value of the static sectorial moment Sω was calculated using the value τω/Mω, obtained from the source as (Iω = 1041229484 cm6): Sω = τωIωt / Mω;

** The value of the static moment Sv was calculated using the value τu/Qu, obtained from the source as (Iv = 1849016 cm4): Sv = τuIvt / Qu.

 

Element number

Vertex number

Tangential stress τω, kN/cm2

(at Mω = 107, kNcm)

Tangential stress τu, kN/cm2

(at Qu = 105, kN)

Source

TONUS

Deviation,

%

Source

TONUS

Deviation,

%

1

1

0

0

0

0

0

0

1

2

843

844

0,12

197

197

0

2

2

626

627

0,16

40

40

0

2

3

614

615

0,16

157

157

0

3

3

644

645

0,16

98

98

0

6

7

209

209

0

162

163

0,6

6

8

212

212

0

10

0

7

8

357

357

0

172

172

0

9

2

434

434

0

473

473

0

9

7

502

503

0,20

390

390

0

10

3

61

61

0

510

510

0

10

8

348

349

0,29

436

436

0

 

Vertex number

Sectorial area, cm2

Source

TONUS

Deviation, %

1

+3241

+3241

0

2

–1483

–1483

0

3

–1102

–1102

0

7

–261

–261

0

8

+249

+249

0