A novel non-contacting single-coil electromagnetic hole expansion process to improve the fatigue performance of hole component

Geng, Huihui; Xu, Xiaofei; Lai, Zhipeng; Cao, Quanliang; Li, Liang

doi:10.1016/j.ijfatigue.2022.106924

Cited by 6 publications

(7 citation statements)

References 30 publications

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“…This method improves the fatigue life of the specimen compared to the mandrel cold expansion method. In order to overcome the limitations of the mechanical CE process, scientists have provided a new idea to ream fasteners with electromagnetic force, which avoids the direct contact of the mandrel or sleeve with the hole wall and provides good integrity of the hole wall, as shown in Figure 17b,d,e [91][92][93]. This is mainly due to the ability of these methods to reduce the resistance of CE, perform non-contact machining, and make residual stresses more homogeneous, resulting in a higher fatigue life than SCE.…”

Section: Application Of New Processesmentioning

confidence: 99%

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Factors Influencing Residual Stresses in Cold Expansion and Their Effects on Fatigue Life—A Review

Su,

Huang,

et al. 2023

Coatings

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Cold expansion technology has been widely used in aviation industries as an effective method of improving the fatigue performance of fastener holes. It can improve the fatigue life several times over without adding weight, meeting the growing demand for lightweight and durable aircraft structures. In recent years, it has been extensively studied through extensive experiments and finite element simulations to analyze the residual stresses around the fastener hole. Appropriate process parameters lead to the generation of beneficial residual stresses that influence the material microstructure, thereby improving the fatigue life of the component. This paper summarized factors influencing residual stresses in cold expansion and their effects on fatigue life, and the strengthening mechanism, parameter optimization, and effect of anti-fatigue are discussed from the point of view of the residual stress and microstructure. The development of new cold expansion technologies and the research directions that can realize anti-fatigue technology efficiently are proposed.

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Section: Application Of New Processesmentioning

confidence: 99%

“…x FOR PEER REVIEW 18 of 22 shown in Figure 17b,d,e. [91][92][93]. This is mainly due to the ability of these methods to reduce the resistance of CE, perform non-contact machining, and make residual stresses more homogeneous, resulting in a higher fatigue life than SCE.…”

Section: Application Of New Processesmentioning

confidence: 99%

Factors Influencing Residual Stresses in Cold Expansion and Their Effects on Fatigue Life—A Review

Su,

Huang,

et al. 2023

Coatings

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“…In the last few years, various dynamic hole cold-working methods have been presented, which have a common technical basis: an electromagnetic load. They implement two concepts: mechanical cold-working methods based on electromagnetic driving [19,20] and a non-contact electromagnetic cold hole expansion process based on radial pulsed electromagnetic force [21,22]. For example, Guo et al [19] proposed a novel dynamic cold expansion method using a mandrel driven by a driving head through the electromagnetic dynamic force.…”

Section: Introductionmentioning

confidence: 99%

“…In 2A12-T4 aluminum alloy, their proposed process was more efficient compared with the conventional mechanical cold expansion process because of the non-contact characteristic and uniform residual stress distribution. In relevant research, Geng et al [22] proposed a simplified single-coil non-contact electromagnetic cold hole expansion process. Their fatigue test results showed significant improvements in the fatigue performance of the 2A12-T4 specimen, and good surface integrity and grain refinement were observed near the hole.…”

Section: Introductionmentioning

confidence: 99%

Modified Split Mandrel Method and Equipment to Improve the Fatigue Performance of Structural Components with Fastener Holes

Maximov,

Duncheva,

Anchev

et al. 2024

Metals

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Fastener holes are among the most common natural stress concentrators in metal structures. The life cycles of various structural elements, such as those in aircraft structures, automobiles, and rail-end bolt joints, are limited by fatigue damage around the holes. An effective approach to delay the formation and growth of fatigue macrocracks is to introduce residual hoop compressive stresses around the holes. Two methods have become established in the prestressing of fastener holes in aircraft components, split sleeve and split mandrel, which implement one-sided processes. The common disadvantage of both methods is the complex procedure due to the need for high accuracy of the initial holes. This article presents a new modified split mandrel method providing the same tightness (interference fit) with a wide tolerance of the pre-drilled hole diameters, reducing the number of technological cycle steps and production costs. То implement the new method, a functionally connected tool and a device with a hydraulic drive were developed. An extensive experimental study of 2024-T3 AA specimens was carried out to evaluate the effectiveness of the method under a high scattering of the pre-drilled holes. The new method provided a deep zone of residual hoop compressive stresses on both faces of the specimens after cold working and after hole final reaming. The removal of a plastically deformed layer around the hole of suitable thickness during the final reaming decreased the axial gradient of residual hoop stress distribution. Fatigue tests on a tensile pulsating cycle verified the effectiveness of the modified split mandrel method to significantly increase the fatigue life by 6.6 times based on 106 cycle fatigue strength compared to the conventional case of machining the holes. The obtained S-N curves for three groups of samples with initial hole diameters of 8.0, 8.1, and 8.2 mm, which were cold worked with the same tightness of 0.32 mm and final reamed, aligned well, indicating that the new method can provide constant fatigue strength for a given stress amplitude.

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“…Several novel processes, which are based on the traditional CE process, were reported in literatures, such as electromagnetic CE, [27][28][29][30] symmetric CE, 31,32 friction stir expansion, 33 ultrasonic impact assistant expansion, 34 and stress wave strengthening. 35 Although these processes can achieve more uniform compressive residual stress and prolong fatigue life compared to the traditional CE process, yet they need more complex tools or procedures, thereby causing more time and cost.…”

Section: Introductionmentioning

confidence: 99%

Investigation on fatigue performance of open‐hole plates treated by dynamic cold expansion under large expansion size based on electromagnetic loading

Zheng,

Cao,

Talemi

2023

Fatigue Fract Eng Mat Struct

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This study aims to explore the upper limit of expansion size in dynamic cold expansion (DCE) and discuss the fatigue life enhancement mechanisms of this process. To achieve this, fatigue tests were conducted and the fractured surfaces were analyzed. Residual stress was measured both experimentally and numerically, and micromorphology was investigated. The stress distributions were also used to predict the fatigue life, with corresponding investigations of static cold expansion (SCE) conducted for comparison. The results indicate that the DCE process can achieve a larger upper limit expansion size than the SCE, leading to an extension of higher fatigue life. Additionally, the DCE induces larger compressive residual stress, especially at the mandrel entrance layer, and more significant grain refinement than the SCE. These factors are considered as the main mechanisms responsible for the fatigue life enhancement in the DCE process. The predicted results were in good agreement with the experimental data.

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A novel non-contacting single-coil electromagnetic hole expansion process to improve the fatigue performance of hole component

Cited by 6 publications

References 30 publications

Factors Influencing Residual Stresses in Cold Expansion and Their Effects on Fatigue Life—A Review

Factors Influencing Residual Stresses in Cold Expansion and Their Effects on Fatigue Life—A Review

Modified Split Mandrel Method and Equipment to Improve the Fatigue Performance of Structural Components with Fastener Holes

Investigation on fatigue performance of open‐hole plates treated by dynamic cold expansion under large expansion size based on electromagnetic loading

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