Simulation of Compressive Strength of Wall Studs Cold-Formed from Advanced High Strength Steel

The objective of this paper is to explore if thin-walled cold-formed steel wall studs cold-formed from advanced high strength steels (AHSS), with yield stress potentially over 1000 MPa (145 ksi), are required to consider additional adjustments in the prediction of their design strength. This question is explored utilizing shell finite element collapse studies through a parametric study. This parametric study covers three steel materials (two AHSS and one mild steel), all 152 mm (6 in.) deep commercial structural lipped channels listed by the Steel Framing Industry Association (SFIA), and two bracing configurations which simulate real bracing conditions commonly used in the cold-formed steel framing industry. The simulated strengths from the finite element models are compared to the predictions by the Direct Strength Method (DSM) in the North American cold-formed steel specification AISI S100-16. Modal identification techniques are also applied to the simulation results to understand the existence and importance of local-distortional and distortional-global buckling mode interactions, and their implications on the code strength predictions are also explored. It is shown that for practical cross-sections and bracing conditions the current Direct Strength Method expressions can accurately predict the compressive strengths of the simulated AHSS walls studs, without additional need for strength reduction nor explicit consideration of new modal interactions. However, it is shown that the shape of the material stress-strain response in addition to yield stress does have some impact on the results. This study marks one of the initial steps towards making AHSS available for use in the cold-formed steel construction industry.

Learning Objectives:
Describe the potential effects in wall studs' performance by switching from mild steel to advanced high strength steel.

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