FRP/GRP/GRE Piping Stress Analysis

Learn about PASS/START-PROF pipe stress analysis software

Video tutorial: FRP/GRP/GRE Piping Stress Analysis using PASS/START-PROF

FRP/GRP/GRE piping analysis follows ISO 14692 standards.

Key differences from steel piping analysis:

• Orthotropic Material Properties: Requires separate consideration of axial and hoop direction stresses. Essential mechanical properties include:

  • E_a - Axial modulus of elasticity
  • E_h - Hoop modulus of elasticity
  • G - Shear modulus
  • v_h/a - Poisson ratio (hoop/axial)
  • v_a/h - Poisson ratio (axial/hoop)
  Consult the material database for details. Properties vary by manufacturer - obtain specific values from suppliers for accurate analysis.

• Thermal and Pressure Expansion: Higher thermal expansion coefficients and significant pressure elongation (Bourdon effect). Account for uneven wall heating using temperature range factor (typically 0.85). Configure in additional pipe properties.

• Failure Envelope Analysis: Uses long-term failure envelopes , , , , instead of single allowable stress. Allowable stresses depend on:

  • Load type factor f₂
  • Temperature factor A₁
  • Chemical resistance factor A₂
  • Fatigue factor A₃
  Separate envelopes for pipes and fittings. See code stress for details.

• Wall Thickness Calculation: Uses liner (t_L) and topcoat (t_c) thickness to determine:

  • Reinforced wall thickness: t_r = t - t_L - t_c
  • Mean diameter: D_r = D - 2·t_c - t_r