Fatigue Hotspot Assessment & Structural Integrity Studies
Course Description
Target Audience
Entry Requirements
- Bachelor’s degree in Mechanical, Structural, Civil, or Marine Engineering
- Minimum 3–5 years of professional experience in structural analysis, fatigue, integrity, or design
- Prior exposure to fatigue analysis, welded structures, or finite element analysis is recommended
This is not an introductory course; it is intended for practicing engineers.
Course Duration
Total Duration: 3 Days
Day 1: Fatigue fundamentals, hotspot identification, fatigue assessment methodologies
Day 2: Fatigue result interpretation, life extension principles, engineering justification of
treatments
Day 3: Quality assurance, integrity integration, and case-based engineering decision workflows
General Learning Outcomes
By the end of the course, participants will be able to:
- Analyze fatigue damage mechanisms in welded structures
- Evaluate fatigue hotspots using probabilistic and deterministic approaches
- Interpret fatigue life predictions for engineering decision-making
- Justify fatigue life extension strategies using recognized engineering principles
- Integrate fatigue mitigation measures into long-term structural integrity management plans
Module 1 – Fundamentals of Fatigue in Welded Structures
• Fatigue mechanisms in welded steel details
• Crack initiation versus crack propagation
• Influence of geometry, weld quality, and residual stresses
• High-cycle versus low-cycle fatigue regimes
• Introduction to S–N curves and fatigue classes
Learning Outcomes from this Module:
– Describe fatigue mechanisms in welded joints (Understand)
– Explain the influence of geometry and residual stresses on fatigue behavior (Understand)
– Differentiate between fatigue regimes and their implications (Analyze)
Module 2 – Fatigue Hotspot Identification
• Definition and characteristics of fatigue hotspots
• Typical hotspot locations in welded structural systems
• Role of geometric discontinuities and stress concentrations
• Influence of fabrication quality and as-built deviations
• Categorization of hotspots by remaining fatigue life
Learning Outcomes from this Module:
– Identify fatigue hotspots in welded structures (Apply)
– Classify hotspots based on fatigue criticality and remaining life (Analyze)
– Explain why cracking may occur outside idealized analytical locations (Understand)
Module 3 – Fatigue Assessment Methodologies
• Deterministic fatigue analysis using local stress and FEA-based approaches
• Probabilistic (stochastic) fatigue assessment concepts
• Comparison of assessment methodologies: assumptions, outputs, and implications
• Risk-based versus optimization-based fatigue management philosophies
Learning Outcomes from this Module:
– Compare deterministic and probabilistic fatigue assessment approaches (Analyze)
– Interpret uncertainty and probabilistic fatigue outputs (Analyze)
– Evaluate the suitability of different methods for integrity decision-making (Evaluate)
Module 4 – Interpreting Fatigue Results for Engineering Decisions
• Conversion of fatigue life (years) into equivalent stress ranges
• Understanding probability of failure and reliability levels
• Remaining fatigue life versus consumed fatigue life
• Prioritization of fatigue-critical structural locations
• Definition of short-life, medium-life, and low-risk categories
Learning Outcomes from this Module:
– Convert fatigue life predictions into equivalent stress ranges (Apply)
– Interpret fatigue results in terms of reliability and risk (Analyze)
– Prioritize fatigue hotspots for mitigation actions (Evaluate)
Module 5 – Fatigue Life Extension Principles
• Fatigue strength improvement mechanisms
• Role of weld toe geometry modification
• Influence of compressive residual stresses
• Rotation of S–N curves and slope effects
• Limitations and boundary conditions of fatigue improvement techniques
Learning Outcomes from this Module:
– Explain fatigue life extension mechanisms (Understand)
– Analyze the influence of residual stresses and geometry modification (Analyze)
– Assess when fatigue improvement techniques are technically justified (Evaluate)
Module 6 – Engineering Basis for Treatment Extent
• Local stress gradients and real-world crack initiation zones
• Differences between numerical hotspots and practical fatigue regions
• Justification of treatment envelope lengths
• Effects of multipass welds and start-stop features
• Conservative engineering allowances versus analytical minimums
Learning Outcomes from this Module:
– Analyze discrepancies between analytical hotspots and observed fatigue damage (Analyze)
– Justify treatment extents using engineering judgment (Evaluate)
– Formulate defensible fatigue mitigation scopes (Create)
Module 7 – Quality Assurance, Verification & Risk Control
• Pre-treatment inspection philosophy
• Identification of unacceptable weld conditions
• Post-treatment verification principles
• Documentation and traceability requirements
• Long-term monitoring and reassessment strategies
Learning Outcomes from this Module:
– Define quality assurance and inspection requirements (Understand)
– Evaluate inspection findings to confirm treatment suitability (Evaluate)
– Develop verification and documentation strategies for integrity management (Create)
Module 8 – Integration into Structural Integrity Management
• Linking fatigue mitigation to inspection planning
• Balancing treated versus untreated fatigue-critical elements
• Avoiding unintended fatigue hierarchy shifts
• Maintenance strategy optimization
• Life-extension decision frameworks
Learning Outcomes from this Module:
– Integrate mitigation into integrity plans (Apply)
– Evaluate system-level impacts of localized fatigue improvements (Evaluate)
– Design long-term fatigue management strategies (Create)