Stress Relief in Pressurized Fluid Flow System Bore Intersections
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Solution Overview
Problem
High-pressure fluid flow systems, such as fuel injectors, face significant failure risks due to tensile stress at intersections between primary and secondary bores, which can lead to crack propagation and early component failure, and conventional stress relief methods like shot peening and autofrettage are expensive and may cause robustness issues.
Innovation Solution
A method involving loading elements to generate compressive hoop stress at the intersection between primary and secondary bores, using stress relief layers to counteract tensile stress without the need for pre-processing steps like shot peening or autofrettage, by applying loading forces that induce Poisson effect stress and bending moments to create compressive stress at the intersection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stress relief methods like shot peening and autofrettage are used, then tensile stress at bore intersections is reduced, but production costs increase and robustness issues may occur
Solution Approach 1:
The component structure itself generates the stress relief effect through its geometric design. The specific configuration of the bore intersection and surrounding material allows the component to automatically counteract tensile stresses during operation without requiring external processing or additional components, thereby eliminating the need for expensive shot peening or autofrettage processes.
Solution Approach 2:
The invention modifies the geometric parameters of the bore intersection, specifically optimizing the radius and curvature at the intersection point. By changing these dimensional parameters, the stress distribution is altered to reduce tensile stress concentration, achieving stress relief through design rather than post-processing.
2Ease of manufacture
If material grade is reduced to lower product cost, then manufacturing cost decreases, but material strength decreases and failure risk at intersections increases
Solution Approach 1:
The invention applies local quality optimization at the bore intersection by creating a specific geometric configuration that provides enhanced stress distribution characteristics at this critical location. This localized geometric modification ensures that even lower-grade materials can withstand the stresses at the intersection point, allowing cost-effective material selection without compromising overall component reliability.
3Reliability
If bore intersection geometry is modified to reduce tensile stress, then stress concentration is reduced, but design complexity and manufacturing difficulty increase
Solution Approach 1:
The stress relief geometry is built into the component design from the outset, during the initial manufacturing process. By incorporating the optimized bore intersection geometry as a preliminary design feature rather than applying it as a subsequent modification, the invention avoids additional manufacturing steps and maintains design simplicity while achieving stress reduction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces tensile stress at failure points, enhancing component durability without increasing production costs and avoiding robustness problems associated with conventional methods, allowing the system to operate within a compressive stress regime that is better tolerated by materials.
Implementation Method 1
generating a compressive hoop stress where the first face of the drilled element is loaded by the first loading element
Implementation Method 2
applying loading forces that induce Poisson effect stress and bending moments to create compressive stress at the intersection
Data Source
AI summary
A method of reducing tensile stress within a drilled element 100 at an intersection 130 between a primary bore 110 and a secondary bore 120 comprises the following steps. A first face of the drilled element 100 is loaded with a first loading element. A compressive hoop stress is generated where the first face of the drilled element 100 is loaded by the first loading element, and the intersection 130 is sufficiently close to the first face of the drilled element 100 such that the compressive hoop stress counteracts tensile stress in the drilled element 100 at the intersection 130. A suitable drilled element 100 and fluid flow systems, such as a fuel injector, including such a drilled element 100 are also described.