ABSTRACT
The data used to develop the FE and material models are reported in Martinez-Saucedo & Packer (2007) and Martinez-Saucedo et al. (2008). A non-linear material, multi-linear true stress-true strain (Tσ-Tε) curve was employed to reproduce the gusset plate, CHS and weld material properties. Weld material was represented by the CHS material properties. The Tσ-Tε curves were generated based on the engineering (σ-ε) relations (from coupon tests under monotonic loading) and a method suggested by Martinez-Saucedo et al. (2006) to deal with coupons having a rectangular cross-section. Whereas isotropic hardening was assumed for monotonic analysis, kinematic hardening has been assumed for cyclic analysis. A preliminary FE analysis of the braces, using curve material properties from monotonic tests, resulted in loads exceeding those from the laboratory. The reason for this is that the hardening function in a cyclic hardening model is different to the monotonic case, due to the effects of consolidation induced by the cyclic loading (Lemaitre & Chaboche 1994). In the absence of coupon test results under low cycle fatigue cyclic loading, to capture the hardening function, the static material curves were scaled down to represent the anticipated cyclic hardening response. It was found that scaling the static material curves to 94% of their original value (see Fig. 3) was sufficient to allow the FE models to closely predict the response measured for the test specimens.
