Numerical Modeling of Duplex Stainless Steel Structures

Transcription

1 August 31 to September 2011 Numerical Modeling of Duplex Stainless Steel Structures Priscila das N. Pereira William M. Pereira Isabella Pinheiro Gueiros Luciano Rodrigues Ornelas de Lima Pedro Colmar Gonçalves da Silva Vellasco José Guilherme Santos da Silva Structural Engin. Department - UERJ Rio de Janeiro, Brasil

2 2 Summary Introduction Objectives & Methodology Design Codes Recommendations Numerical Model Parametric Analysis Results Analysis & Discussion Concluding Remarks

3 3 Introduction Stainless steel various types of constructions high corrosion resistance, durability, fire resistance, ease of maintenance, appearance and aesthetics Cost reduction less need for structure maintenance & increase in its capacity to dissipate impact loads stainless steel structure reliability

4 4 Introduction Stainless steel structures examples Arco de Malizia, Italy Piove di Sacco, Italy

5 5 Objectives / Methodology Development of a numerical model based on FEM Evaluate LTB Beams Behaviour RHS Tubular Joint Resistance imperfection introduction

6 6 Design Rules Duplex Stainless Steel Beams Eurocode 3 Particular case non-symmetrical patterns different bending moment diagrams ULS LTB based on M cr 2 2 C 1 EIZ k z C M cr 2 (k z L) k W I k z rotation end conditions k w warping end conditions z g relation between load application point and shear centre z j degree of assymmetry of the cross section W Z 2 (k z L) GIT 2 C 2 z 2 g C2 z g EI Z Geometrical characteristics updated for Castellar beam properties

7 ULS - chord face failure 7 Design Rules RHS Tubular Joints Eurocode 3, CIDECT & Feng & Young Formulation Eurocode 3 N k 2 n y ,Rd 4. 1 / 1 1 CIDECT N * 1 Q.f.t M5 1.sen sen u.q f f y0.t. sen 2 0 i Q sen 1 1 u f i Q 1 n C Feng & Young N1 np A 1.N.1,1 A b t 0 N k.f.t 2 n y / 1 1 M5 1.sen sen

8 8 Design Rules Deformation limit proposed by Lu et al. T Joints Serviceability limit (N s ) D s = 0.01d 0 Ultimate strength (N u ) D u = 0.03d 0 If N u /N s 1.5 N u If N u /N s > 1.5 N s P N u N s D 1%d 0 3%d 0 D

9 9 Numerical Models Beams shell elements SHELL181 beam member plates mid-surfaces Material multi-linear s x e Geometrical Non-linearity (Updated Lagrangian) (Identification of yielded points) imperfection introduction eigenvalue analysis

10 applied bending moment [kn] 10 Numerical Models Imperfection Considerations Load step 1 Eigenvector for 1 st buckling mode Application of imperfection factor based on EC3 limits Load step 2 50 Nonlinear analysis material and geometrical nonlinearities vertical displcament [mm]

11 11 Numerical Models RHS Joints shell elements SHELL281 beam member plates mid-surfaces Material multi-linear s x e Section (h x b x t) E s p s 0.1 s y = s 0.2 s 0.5 s 1.0 s u e f (%) Chord 160x80x Brace 40x40x Geometrical Non-linearity (Updated Lagrangian) (Identification of yielded points) X Feng & Young Experiments

12 Load [kn] 12 Numerical Model Calibration Experimental results Feng &Young Numerical Experimental Displacement [mm]

13 13 Parametrical Analysis Duplex stainless steel beams LTB W300x150 welded profile 300mm height, 160mm flange width, 9.5mm flange thickness &4.7mm web thickness 8 span lengths from 1 to 8m corresponding l LT between 0.57 & 3.15

14 14 Parametrical Analysis Duplex stainless steel beams LTB M/M pl Eurocode 3 Numerical - Ansys l LT Numerical versus Eurocode 3

15 applied bending moment [kn] 15 Parametrical Analysis Duplex stainless steel beams LTB vertical displcament [mm] 7m span Ultimate bending moment = kn.m von Mises stress distribution (in MPa) observed plastic bending moment resistance not reached in this case, i.e., kn.m Adopted yield stress for duplex stainless steel MPa

16 16 Parametrical Analysis RHS duplex stainless steel joints Geometry Model ID Chord Brace β 2 h 0 b 0 t 0 h 1 b 1 t

17 17 Parametrical Analysis Model ID RHS duplex stainless steel joints N u N s N u /N s N def N 1,Rd N 1 * N 1np EC3 N N 1,Rd def CIDECT Feng & Young N N * 1 def N N 1np def

18 18 Final Remarks Present paper evaluation lateral buckling capacity of duplex stainless steel beams & resistance tubular T joints between RHS members constituted duplex stainless steel Results discussed & compared stress distribution, force-displacement curves, etc. Numerical & analytical curves LTB beams analysis Eurocode 3 equations related these ULS for carbon steel beams can also be used for duplex stainless steel profiles

19 19 Final Remarks RHS joints, new CIDECT formulation better approximation numerical results when compared with Eurocode 3 results When these two values compared with the Feng and Young values, concluded this formulation presented better results when compared two first ones. Acknowledgements: CAPES, CNPq, FAPERJ and UERJ financial support provided to enable the development of this work

20 20 Acknowledgements Thanks for your attention Contacts: and