This project involved the structural design and analysis of crane-lifting lugs for industrial transformers manufactured by ABB. The transformers were going to an offshore location, so the lugs needed to handle adverse weather and meet the client’s specific standards. The core challenge: make sure the lugs could safely handle operational stresses during lifting within tight geometric and material constraints.

My scope of involvement and design process

I was the lead structural engineer for this component, responsible for the full design lifecycle.

What I did:

  • Requirements and constraints:

    • Reviewed client specifications and operational manuals to nail down design parameters and performance expectations.
    • Worked directly with the client to confirm scope, deliverables, permissible materials, geometric limits, and logistics.
    • Flagged potential conflicts with other engineering disciplines early to avoid surprises during integration.

  • FEM and stress analysis:

    • Built detailed FEM models of the transformer lugs in RFEM.
    • Ran stress analysis using client-specified material properties and load cases from governing lifting codes.
    • Found critical stress concentrations in the initial lug geometry that limited lifting capacity and didn’t meet required safety factors.

  • Design optimization:

    • Redesigned and optimized the lug geometry to fix the stress concentrations. This meant iterative adjustments to strengthen weaker junctions and create a better load path.
    • Kept the revised design within the original project constraints - same materials, same dimensional limits.
    • Kept the client updated throughout with regular progress reports on iterations, findings, and proposed changes.

  • Reporting and finalization:

    • Wrote an engineering report covering analytical findings, design methodology, recommendations, and alternate lug profiles.
    • Got client approval on the optimized design.
    • Produced final engineering drawings, sealed by a P.Eng., for fabrication.

What I delivered

  • Designed and validated transformer lifting lugs that met the offshore performance requirements and client standards.
  • Resolved the stress concentration issues through FEM analysis and geometric optimization, significantly improving load-bearing capacity.
  • Delivered a detailed design report and P.Eng. sealed fabrication drawings.
  • The fabricated lugs were installed on the transformers, which were lifted, transported, and secured at their final offshore location - performing as designed.