Segmented Indenter Pressing for Large Hole Fatigue Life
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Solution Overview
Problem
Conventional methods for improving the fatigue life of metal members with holes require large press machines due to the proportional increase in press load with hole size, limiting the size of holes that can be effectively processed.
Innovation Solution
A metal member manufacturing method and apparatus that distribute the press load by pressing multiple portions of the hole formation region sequentially, using an indenter with a press surface divided into sectors, allowing for the application of residual stress around large holes with a relatively low press load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pressing method is used to improve fatigue life of metal members with holes, then the fatigue life is improved by giving compression residual stress around the hole, but the press load becomes large in proportion to the area of the hole, requiring large-sized press machines and limiting the maximum hole size that can be processed
Solution Approach 1:
The pressing operation is divided into multiple sequential steps, with the press surface divided into a first pressing region and a second pressing region. The first pressing region applies compression residual stress to the metal material while the second pressing region remains uncompressed, creating a differential stress state that improves fatigue life without requiring proportionally large press loads across the entire hole area.
2Adaptability or versatility
If the hole size is increased, then the structural application range is expanded, but the press load increases proportionally to the hole area, requiring larger press machines
Solution Approach 1:
By segmenting the press surface into first and second pressing regions, the method enables processing of larger holes without proportionally increasing the required press load. The first pressing region concentrates the compressive stress application where it is most effective for fatigue life improvement, while the second pressing region remains uncompressed, allowing larger hole sizes to be accommodated with the same press machine capacity.
3Reliability
If compression residual stress is given around the hole through conventional pressing, then the fatigue life is improved, but large-sized press machines are required which increases device complexity and cost
Solution Approach 1:
The press surface is segmented into first and second pressing regions, allowing the use of smaller press machines. The first pressing region applies compression residual stress to improve fatigue life, while the second pressing region remains uncompressed. This segmentation enables effective fatigue life improvement without requiring large-sized press machines, thereby reducing device complexity and cost.
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
The method effectively improves the fatigue life of metal members with large holes by reducing the necessary press load, enabling the processing of holes that would otherwise require larger machines, while maintaining the strength and accuracy of the dimple surface.
Implementation Method 1
A plastic deformation region 294 is formed around the dimple 293
Implementation Method 2
Because a compression residual stress is given around the through-hole by opening the through-hole in the dimple 293 of the hole formation region with a drill 300, the fatigue life of the work piece 290 is improved
Data Source
AI summary
A metal member manufacturing method is achieved by pressing a second region of a metal material without pressing a first region of the metal material, and pressing the first region without pressing the second region. The metal material has a hole formation region in which one through-hole is to be formed. The first region and the second region are contained in the hole formation region.