A General determination method of non-linear equivalent material properties for perforated plates

Kasahara, Naoto; Kawasaki, Nobuchika ; Wakai, Takashi ; Takasho, Hideki*

Tubesheet structures utilized in heat exchangers have complex perforated portions. For design analysis, axi-symmetric models with equivalent materials of perforated plate are conventionally adopted to simplify perforated portions. ASME Sec.III Appendix A-8000 provides elastic constants for equivalent materials of perforated plate. In the case of elevated temperature reactors, elastic-plastic-creep deformation occurs in tubesheets. Therefore, design of these structures requires simplified models with non-linear equivalent materials for perforated plate. This study proposes a general determination method of non-linear equivalent material properties for perforated plates. Perforated plates have their own effective stress ratio (ESR). ESR is a function of geometry only and is independent from constitutive equations. ESR can determine non-linear equivalent material properties of perforated plates for any kind of constitutive equations of base metals.