Extremely-Low-Cycle Fatigue Damage for Beam-to-Column Welded Joints Using Structural Details

Area of Science:

• Structural Engineering
• Materials Science
• Mechanical Engineering

Background:

• Steel structures are vulnerable to seismic activity, leading to fatigue damage in welded joints.
• Accurate evaluation of extremely-low-cycle fatigue (ELCF) is crucial for seismic resilience.
• Existing fatigue models require refinement for complex structural details.

Purpose of the Study:

• To evaluate ELCF damage in beam-to-column welded joints under seismic loading.
• To investigate fatigue damage models based on structural detail parameters.
• To assess the applicability of modified fatigue models using experimental data.

Main Methods:

• Experimental fatigue testing of plate butt weld (PB) and cruciform load-carrying groove weld (CLG) specimens.
• Testing of full-scale steel welded beam-to-column joints to determine stress/strain contributions.
• Modification and comparison of the Fatemi-Socie (FS) and Shang-Wang (SW) fatigue damage models.

Main Results:

• The modified FS model, incorporating CLG fatigue properties, effectively predicts crack initiation life.
• Experimental data validates the use of structural detail parameters in ELCF assessment.
• The study demonstrates the superior performance of the modified FS model with CLG properties.

Conclusions:

• The modified FS model with CLG fatigue properties is suitable for evaluating ELCF damage in seismic-loaded steel joints.
• This approach enables accurate prediction of crack initiation and damage evolution.
• Further research can build upon these findings for advanced damage analysis.