蒸気タービンフォーク型翼植込部の低サイクル疲労寿命評価

概要

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A new evaluation method was developed for low-cycle fatigue life for fork-type root attachments of long steam turbine blades. In this study, low-cycle fatigue life was estimated by calculating the micro crack growth life under a steep strain distribution, using the micro-crack growth rate, which is proportional to the effective crack length according to non-linear fracture mechanics. To verify this evaluation method, low-cycle fatigue tests on pin joint models were conducted, in which the crack growth behavior at the inner surface of the pin hole was observed by interrupting the tests. The estimated results for micro-crack growth behavior agreed well with the measured results. To obtain the local strain range distribution for fork-type root attachments, a two-step FEM analysis was proposed, including three-dimensional analysis of a whole-blade model and two-dimensional elastic-plastic contact analysis of a single blade-fork model.
社団法人日本機械学会の論文
2002-02-25