Structural Integrity

EWI offers customers structural integrity assessments and recommendations for metal structures based on material testing, design analysis, fabrication methods and loading conditions.

Nondestructive Evaluation

Resonant Fatigue System

EWI supports the manufacturing industry through the development and incorporation of testing, assessment and prevention technology for cracking and damage of structures. Our team, with more than 75 years of combined experience, specializes in fracture, fatigue, and time-based degradation of metal properties. We focus primarily on welded structures, using EWI’s extensive welding, forming and metallographic capability on-site for assessments. Beyond failure assessment, we are able to use the approach of preventing cracks as a central basis of designing larger systems, where crack-related failure modes are particularly troublesome.

EWI’s structural integrity group offers specialized knowledge in welded structure damage assessments, design to avoid structural damage, material qualification testing, and test method development. The following list provides a sample of our technical expertise.

Technical Expertise

  • Material Preproduction Qualification Testing for offshore oil & gas infrastructure
    • Requires specialized heat affected zone welding & fracture toughness test procedures
  • General fracture toughness and fatigue testing
    • CTOD, J, R-curve, fatigue crack growth rate, fatigue life characterization (S-N curves)
  • Low constraint fracture testing such as testing with short cracks or tension testing
  • Time-dependent fracture tests (step-wise incremental loading, sustained load cracking, etc.)
  • Specialized weld or HAZ failure analysis
  • Weld and HAZ microstructural assessments
  • Fitness-for-service analyses
    • Supports service life estimation and structural design requirements
    • Critical flaw size determination (supporting field inspection targets)

Equipment and Lab Resources

  • 5 kip to 220 kip servohydraulic tensile testing machines with controllers for cyclic loading capability
  • 500 kip compression machine
  • 10 kip and 60 kip screw tensile testing machines
  • Air turbine hole drilling residual stress measurement system
  • Specialized software for fracture toughness parameter determination
  • Two drop towers
  • Bend testing fixtures including a wrap-around format bend tester
  • Digital Image Correlation measurement of localized strain for dissimilar welds

Over the years, EWI’s structural integrity team has used its expertise to push the envelope in materials performance to help our clients succeed. Our high-impact projects have included:

  • Performing resonant fatigue testing of specialized materials, offshore steels, titanium, titanium composites, and aluminum to steel joints
  • Qualifying materials for their heat affected zone fracture properties
  • Designing welding approaches and qualifying procedures for repair of oil wells below the wellhead
  • Defining the fatigue performance capabilities of welded titanium
  • Performing step-wise increasing loading tests on high strength steel exposed to simulated seawater
  • Assessing the thermal fatigue resistance of steel aluminizing rollers and ways of improving them
  • Evaluating the splitting resistance of pipeline steels and the splits effect on other types of fracture
  • Choosing among fatigue improvement methods and guiding their application
  • Assessment of wind-induced vibration resistance of utility tower weldments

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