14 LOCAL slendernesscW14FI: W14x233 with variable Flange thickness, varies Independently from all other dimensionsW14FR: W14x233 with variable Flange thickness, but the web thickness set so that the Ratio of the flange-to-web thickness remains the same as the original W14x233W36FR: W36x330 with variable Web thickness, but the flange thickness set so that the Ratio of the flange-to-web thickness remains the same as the original W36x330W36WI: W36x330 section with variable Web thickness, that varies Independently from all other dimensions
18 Overview Motivation Cross-section stability Design methods FE parametric studyStrain DistributionsOngoing work
19 Results x W36x330 Thicker Original Thinner W36WI Pn, kips W36x233 thicker (recall tw is varied here) specimens develop significant strain hardening (in compression!) while the thinner specimens exhibit less displacement before collapseTake them through the whole plotThinnerDisplacement, in.
21 Membrane longitudinal stress ~ Zero= YieldShown is the membrane or mid-plane longitudinal stress essentially at peak load/collapse. Areas in blue indicate regions where the applied load is being carried.In all the section the flange is carrying the load, and basically uniformly. Recall from an AISC standpoint these are all compact flangesThe web carries a variable amount of load; though even in the thick section some local buckling reduction is experienced, not consistent with AISC which says this is a compact webOverall the notion of an eff. Width for the web seems generally supported by the stress contoursFurther reductions in the web and flange are certainly dis-similarlOriginalW36x330ThickerwebThinnerweb
22 Membrane plastic strain ~ 10ey~ ZeroPlastic strain provides a look at collapse again membrane plastic strainIn thin section yielded flanges, but elastically buckling webIn the original section you have yielding in both flange and web, but recall stress was still dominant in the flangeThicker section shows less yield in the web compared with the original..RED indicates that the section can chew up a lot of energyOriginalW36x330ThickerwebThinnerweb