Variable Radius Fillet Turbine Blade Stress Distribution
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Solution Overview
Problem
Turbine blades in gas turbine engines are prone to mechanical failure due to high temperatures and stresses, leading to crack initiation and propagation, which can result in component breakage and unscheduled shutdowns.
Innovation Solution
Incorporating a variable radius fillet within the pocket of the turbine blade, extending between the forward and aft buttresses, with a radius that increases from the forward to the aft buttress, to distribute and reduce peak stresses, and optionally including a support pad to further alleviate stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a constant radius fillet is used in the pocket of the turbine blade, then the manufacturing process is simple, but the peak stresses are high leading to crack initiation and propagation
Solution Approach 1:
The patent applies local quality by transitioning from a constant radius fillet to a variable radius fillet that changes along the axial direction. The fillet radius is smaller near the forward buttress and larger near the aft buttress, creating localized stress distribution zones that prevent crack initiation and propagation while maintaining manufacturing feasibility through additive manufacturing processes.
2Reliability
If the fillet radius is increased to reduce stress concentrations, then crack propagation is prevented, but the component cross-section is reduced leading to potential breakage
Solution Approach 1:
The patent applies dynamics by making the fillet radius variable rather than constant. The radius dynamically changes along the axial direction, being smaller near the forward buttress to maintain strength and larger near the aft buttress to reduce stress concentrations and prevent crack propagation, thus optimizing both breakage resistance and crack resistance.
3Stress or pressure
If a variable radius fillet is implemented, then peak stresses are reduced by up to 35%, but the manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by varying the fillet radius parameter along the axial direction. This creates a gradient in the fillet geometry that reduces peak stresses by up to 35% while the complex geometry can be manufactured using additive manufacturing processes that can handle variable cross-sections.
Data Source
AI summary
A turbine blade is disclosed. The turbine blade may include a platform, an airfoil extending from one side of the platform, and a neck extending from another side of the platform, wherein the neck includes a forward buttress and an aft buttress. The turbine blade may further include a root extending from the neck, a pocket defined by a plurality of walls and located between the forward buttress and the aft buttress, and a variable radius fillet. The variable radius fillet may be disposed within the pocket and extend between the forward buttress and the aft buttress, wherein a radius of the variable radius fillet increases from the forward buttress to the aft buttress.