An Investigation on Base Metal Block Shear Strength of Ferritic Stainless Steel Welded Connection

Abstract

This study develops a finite element analysis model to predict the ultimate strength of the base metal block shear fracture based on previous experimental results and compares the experimental results with the analysis results to verify the effectiveness of the analysis model. This study also analyzed additional variables of the welding direction and weld length on the applied load to investigate the structural behaviors and fracture conditions. In addition, predicted strength according to the analysis results were compared with those by the current design equations, and the equations proposed by previous researchers. As a result, the design formula by the current design equations, such as Korea Building Code (KBC)/American Institute of Steel Construction (AISC) and European Code (EC3), and the equations proposed by Oosterhof and Driver underestimated the base metal block shear strength of ferritic stainless steel by up to 42%. Equations suggested by Topkaya and Lee et al. for carbon steel and austenitic stainless steel welded connections provided more accurate strength predictions, while they did not reflect the difference of material properties. Therefore, this study proposed a modified strength equation for ferritic stainless steel welded connection with base metal block shear fracture considering the stress triaxiality effect of the welded connection and the material properties of ferritic stainless steel.

Effects of material property and thickness on block shear strength in lean duplex stainless steel welded connections

“…It can be noted that the material properties (refer to Section 3.1) of austenitic stainless steel (STS304L) and ferritic stainless steel (STS430) in previous studies (Lee et al, 2018e; Yuk et al, 2019g) on the base metal block shear fracture strength are different from those of lean duplex stainless steel STS329FLD used in this study.…”

“…Block shear fracture strength equation, equation (7), was proposed for ferritic stainless steel (average yield stress, Fy = 259.93 MPa; tensile strength, Fu = 412.87 MPa; stress enhancement, Fu/Fy = 1.59; elongation at fracture, EL = 42.28%; and nominal plate thickness =3.0 mm) welded connections by Yuk et al(2019g), and the ratio for the proposed design strengths against experimental and analysis strengths was 0.95 on average, which stably evaluated the block shear fracture strength of the STS430 welded connections.…”

“…For this reason, their design predictions have been found to be quite conservative for the block shear strength of welded connections. Recent experimental and numerical studies on the block shear behaviours of welded connections fabricated with nominal 3.0 mm thick cold-formed austenitic stainless and ferritic stainless steel have conducted (Lee et al, 2018e, 2019d; Yuk et al, 2019g) and revised block shear strength equations were suggested considering the material properties difference of each stainless steel.…”

Finite Element Analysis on Block Shear Mechanism of Lean Duplex Stainless Steel Welded Connections

“…However, the constraint effect has not yet been demonstrated. Topkaya [12], Oosterhof & Driver [13], and Yuk et al [14] have pointed out that the block shear mechanism in welded connection under the lateral constriction promoted by the weldment is significantly different from the bolted case. The current design specifications have still not provided separate block shear equations for welded connection.…”

Simulation of the Hot Deformation and Fracture Behavior of Reduced Activation Ferritic/Martensitic 13CrMoNbV Steel

“…The most famous is the critical level of accumulative energy [2] and the critical value of triaxial stress [3,4]. Moreover, mathematical models of flow stress are needed to correctly predict the hot deformation behavior of materials during industrial production [5][6][7][8][9]; such models can be realized by finite element modeling (FEM) [10][11][12]. Determination of critical plastic deformation until fracture is required to predict hot deformation conditions, which prevent failure of the material [13].…”