A study on the matching of constraint between steam turbine blade and laboratory specimens

Jie Yang,Haofeng Chen,Yuman Liu

doi:10.1177/1687814020922007

Abstract

The matching of constraint between laboratory specimens and actual cracked structures is a key problem of the accurate structure integrity assessment. Different laboratory specimens and the steam turbine blade with different constraints were selected, the matching of constraint between steam turbine blade and laboratory specimens was investigated. The results shown that the steam turbine blade with 2 c = 50 mm, a/2 c = 0.20 has a matching constraint with single edge-notched bend specimen with a/ W = 0.6 and single edge-notched tensile specimen with a/ W = 0.3. The steam turbine blade with 2 c = 50 mm, a/2 c = 0.25 has a matching constraint with single edge-notched bend specimen with a/ W = 0.7. The steam turbine blade with 2 c = 50 mm, a/2 c = 0.30 has a matching constraint with single edge-notched bend specimen with a/ W = 0.5 and single edge-notched tensile specimen with a/ W = 0.1. The steam turbine blade with 2 c = 50 mm, a/2 c = 0.35 has a matching constraint with single edge-notched bend specimen with a/ W = 0.4, compact tension specimen with a/ W = 0.3 and central-cracked tension specimen with a/ W = 0.7. The steam turbine blade with a = 15 mm, a/2 c = 0.30 has a matching constraint with compact tension specimen with a/ W = 0.7 and single edge-notched tensile specimen with a/ W = 0.5. The steam turbine blade with a = 15 mm, a/2 c = 0.40 has a matching constraint with compact tension specimen with a/ W = 0.4. The steam turbine blade with a = 15 mm, a/2 c = 0.50 has a matching constraint with single edge-notched bend specimen with a/ W = 0.5.

Highlights

Constraint is the resistance of a structure against plastic deformation.[1]
The out-of-plane constraint is affected by the specimen dimension parallel to the crack front, and the in-plane constraint is affected by the specimen dimension in the direction of crack propagation
Because the compact tension (CT) specimen is another standard specimen, the matching conditions between steam turbine blades and CT specimens shows that it is not appropriate if only the standard specimen was selected in the structure integrity assessment

Summary

Introduction

Constraint is the resistance of a structure against plastic deformation.[1]. It was divided into out-of-plane constraint and in-plane constraint. Keywords Constraint, matching, steam turbine blade, laboratory specimen, structure integrity assessment In this article, the constraints of cracked steam turbine blades were calculated, and the matching of constraint between the steam turbine blades and laboratory specimens was investigated.

Results

Conclusion