Stress Analysis

Advanced analysis, Fitness-for-service and failure investigation are foremost among the strengths of LPI, Inc. LPI, Inc. has developed these strengths over years of experience in the analysis of structures and components found in a broad range of industries, including construction, utilities, manufacturing, and transportation. In all these endeavors, advanced stress analysis using the finite element method has been a critical part of the complete approach to solving clients' problems. The finite element analysis software used at LPI, Inc. are ANSYS, SAP, and LSDYNA, state-of-the-art commercial software packages recognized throughout industry as the leading products of their kind.

Members of LPI, Inc.'s analytical staff have successfully employed finite element analysis in all of the following areas of structural mechanics:

  • Linear, elastic, static stress analysis, including thermo-structural response under steady-state and transient thermal loads
  • Nonlinear structural analysis, including:
  • Material nonlinearity (e.g., metal plasticity)
  • Geometric nonlinearity (e.g., large deflection/strain/rotation, buckling)
  • Boundary nonlinearity (e.g., contact, both frictional and frictionless)
  • Structural dynamic analysis, including:
    • Mode/frequency analysis
    • Random vibration
    • Harmonic vibration
    • Transient response

Piping Analysis

Performing piping analysis to nuclear standards has become a routine occurrence for most services providers. Performing those services when the loading is unique and transient in behavior is where LPI, Inc. excels. Our engineers have solved complex transient problems, involving waterhammer, harmonic, and flow induced vibration loading. We also extend the standard analyses to perform non-linear and elastic-plastic analyses to calculate the behavior as accurately as possible. We have performed qualification of systems to ASME Class 1 design transients associated with plant life extension support, valve closure transients and pipe break assessments.

LPI, Inc. utilizes the AutoPIPE and ANSYS software codes to perform code qualification of piping.

Wall Thinning Analysis

Wall thinning can occur in pressure boundary equipment, ranging from piping to vessels. LPI, Inc.'s engineers can perform assessments to develop continued component operation, even when wall thicknesses drop below code minimums. LPI, Inc. has experience implementing simplified methods outlined in ASME code cases (such as N-597), ASME's FFS-1 code or utilizing finite element analysis methods to determine local stress distribution. Additionally, fracture mechanics methods can be utilized to ensure flaw stability in the event of loss of integrity at the thinned region.

Buried Piping Analysis

Go To Buried Piping

For more information, please contact Paul Murtagh, Ph.D. by email at, or by phone at (646) 763-8279.