Abstract
The retrofit of notch damaged steel beams is investigated via the experimental testing of nine wide-flange steel beam specimens and finite element simulation. Three notch configurations representing various damage levels were identified, and the beam specimens were retrofitted using carbon fiber reinforced polymer (CFRP) laminates and a recently developed Carbon-fiber Hybrid-polymeric Matrix Composite (CHMC) that has been termed CarbonFlex, and that exhibits superior energy dissipation and ductility properties. The peak-load deflections of the CarbonFlex-retrofitted beams were calculated to be between 67.8% and 73.1% higher than their CFRP-retrofitted counterparts. The results are attributed to the substantially higher damage tolerance of CarbonFlex than conventional carbon-fiber reinforced polymer. Finite element models were developed to investigate the damage mechanism and loading carrying capacities of the beams, and the strain/ stress distributions near the notch tips. The numerical results match closely with the experimentally determined load-deflection curves and the strain fields obtained by the digital imaging correlations (DIC) technique. Both experimental and numerical results clearly indicate the effectiveness of CarbonFlex, as a candidate retrofitting material, for damaged steel structures. Lastly, the micro-mechanisms by which CarbonFlex could sufficiently sustain a significant amount of the peak strength at large deformations are discussed through scanning electron microscopy (SEM) and nano-indentation studies.
| Original language | English |
|---|---|
| Pages (from-to) | 690-702 |
| Number of pages | 13 |
| Journal | Composite Structures |
| Volume | 106 |
| DOIs | |
| State | Published - Dec 2013 |
Funding
This research was partially supported by the Department of Homeland Security (DHS) through the Higher Education Research Experience (HERE) Program, and by the Southeast Region Research Initiative (SERRI) at the Department of Energy’s Oak Ridge National Laboratory (ORNL), DHS Project No. 90300. The authors would especially like to thank Dr. Donald Erdman III from ORNL for his support of the experimental testing procedures and also Dr. Benjamin Thomas, Jr. for his continued support of this research project. The authors also would like to thank Drs. Andrew Wereszczak and Hong Wang at ORNL for their helpful discussions during preparation of the manuscript, and Andrew Bowers at BASF, The Chemical Company for the donation of materials used for the project.
| Funders | Funder number |
|---|---|
| Southeast Region Research Initiative | |
| U.S. Department of Homeland Security | |
| Oak Ridge National Laboratory | 90300 |
Keywords
- Digital imaging correlation (DIC)
- Finite element analysis (FEA)
- Microstructure
- Polymer-matrix composites (PMCs)
- Retrofit
- Steel beam