An Equivalent Structural Stress-Based Frequency-Domain Fatigue Assessment Approach for Welded Structures under Random...

Area of Science:

• Structural Engineering
• Materials Science
• Mechanical Engineering

Background:

• Welded structures face fatigue failures under random loads, causing economic and safety issues.
• Traditional methods (nominal, hotspot, notch stress) struggle with accurate weld stress prediction due to geometric and loading complexities.

Purpose of the Study:

• To introduce a novel frequency-domain fatigue analysis method for welded structures under random loading.
• To enhance the prediction accuracy of fatigue damage and life in welded joints.

Main Methods:

• Developed an Equilibrium Equivalent Structural Stress (EESS)-based approach for frequency-domain fatigue analysis.
• Incorporated structural dynamic properties into the EESS formulations for stress and fatigue damage characterization.
• Validated the method using a welded Rectangular Hollow Section (RHS) T-joint under stationary random fatigue loading.

Main Results:

• The EESS method demonstrated effective characterization of weld toe stresses with a single parameter.
• Numerical results showed good agreement with fatigue test data for the RHS T-joint.
• The EESS approach provided comparable or improved fatigue life predictions versus the hotspot stress method.

Conclusions:

• The proposed EESS-based frequency-domain fatigue analysis is a viable and accurate method for welded structures.
• This approach addresses limitations of traditional methods in predicting fatigue damage under random loading.
• The study highlights the importance of incorporating structural dynamics for precise fatigue assessment of welded components.