The Experts below are selected from a list of 687 Experts worldwide ranked by ideXlab platform

Reza Hojjati Talemi - One of the best experts on this subject based on the ideXlab platform.

  • Numerical study on the influence of artificial internal stress Relief Groove on fretting fatigue in a shrink-fitted assembly
    Tribology International, 2020
    Co-Authors: Diego Erena, J. Vázquez, C. Navarro, Reza Hojjati Talemi
    Abstract:

    Abstract Fretting fatigue failure occurs in shrink-fitted assemblies due to the combination of high stresses and relative displacements near the contact edge. Due to these high stresses, fatigue crack initiates followed by crack propagation until final rupture. Additive manufacturing (AM) is a game changing technology, which enables new component capabilities that cannot be manufactured with conventional techniques. This research work analyses numerically the influence of an artificial internal stress Relief toroidal Groove inside a shrink-fitted shaft, which could be manufactured using AM technology. Due to the toroidal void, the stress/strain fields are redistributed improving the fretting fatigue crack initiation and propagation lifetimes. To do so, 2D finite element models are created in Abaqus software with and without the internal Groove. To estimate the fretting fatigue initiation and propagation lifetime and crack propagation direction, critical plane methods are used. In terms of the crack propagation, eXtended Finite Element Method (XFEM) is used to simulate mixed mode crack advancing in a single mesh structure. Finally, the obtained results with and without void were compared concluding with significant improvements in terms of total fatigue lifetime.

Maria Kashtalyan - One of the best experts on this subject based on the ideXlab platform.

  • threaded connectors for sandwich pipes part 2 optimisation of stress Relief Groove
    International Journal of Pressure Vessels and Piping, 2018
    Co-Authors: Ikechukwu Onyegiri, Maria Kashtalyan
    Abstract:

    Abstract A concept for using snap-fit connectors in sandwich pipes is investigated numerically in two companion papers using a combination of 2D axisymmetric and 3D finite element models in Abaqus. In the Part 1 paper, results of key parametric studies related to the installation analysis of sandwich pipes in deepwater are reported. The modification of the nib Groove to include variable radii, the use of an elastomeric seal coupled with compressive pre-stress and an optimum resin-to-core ratio all proved to enhance the performance of the sandwich pipe snap-fit connectors. The influence of the interlayer adhesion configuration on the stress concentration experienced in the connector is also studied. Furthermore, a comparative study is performed to investigate the mechanical behaviour of the snap-fit connector concept in sandwich pipes and conventional pipe-in-pipe. In the Part 2 paper, an optimisation study is carried out for the stress Relief Groove (SRG) in the pin of the snap-fit connector. A combined parameter is proposed to capture the relationship between the investigated geometric properties and the stress concentration factor at the SRG. It is established that the fillet radius could indeed be used to offset the drop in performance associated with increasing the SRG depth while improving the fatigue characteristics of the connector threads.

  • Threaded Connectors for Sandwich Pipes – Part 2 : Optimisation of Stress Relief Groove
    International Journal of Pressure Vessels and Piping, 2018
    Co-Authors: Ikechukwu Onyegiri, Maria Kashtalyan
    Abstract:

    Abstract A concept for using snap-fit connectors in sandwich pipes is investigated numerically in two companion papers using a combination of 2D axisymmetric and 3D finite element models in Abaqus. In the Part 1 paper, results of key parametric studies related to the installation analysis of sandwich pipes in deepwater are reported. The modification of the nib Groove to include variable radii, the use of an elastomeric seal coupled with compressive pre-stress and an optimum resin-to-core ratio all proved to enhance the performance of the sandwich pipe snap-fit connectors. The influence of the interlayer adhesion configuration on the stress concentration experienced in the connector is also studied. Furthermore, a comparative study is performed to investigate the mechanical behaviour of the snap-fit connector concept in sandwich pipes and conventional pipe-in-pipe. In the Part 2 paper, an optimisation study is carried out for the stress Relief Groove (SRG) in the pin of the snap-fit connector. A combined parameter is proposed to capture the relationship between the investigated geometric properties and the stress concentration factor at the SRG. It is established that the fillet radius could indeed be used to offset the drop in performance associated with increasing the SRG depth while improving the fatigue characteristics of the connector threads.

  • Threaded Connectors for Sandwich Pipes – Part 1 : Parametric & Comparative Studies
    International Journal of Pressure Vessels and Piping, 2018
    Co-Authors: Ikechukwu Onyegiri, Maria Kashtalyan
    Abstract:

    Abstract A concept for using snap-fit connectors in sandwich pipes is investigated numerically in two companion papers using a combination of 2D axisymmetric and 3D finite element models in Abaqus. In the Part 1 paper, results of key parametric studies related to the installation of sandwich pipes in deepwater are reported. The modification of the nib Groove to include variable radii, the use of an elastomeric seal coupled with compressive pre-stress and an optimum resin-to-core ratio all proved to enhance the performance of the sandwich pipe snap-fit connectors. The influence of the interlayer adhesion configuration on the stress concentration experienced in the connector is also studied. Furthermore, a comparative study is performed to investigate the mechanical behaviour of the snap-fit connector concept in sandwich pipes and conventional pipe-in-pipe. In the Part 2 paper, an optimisation study is carried out for the stress Relief Groove (SRG) in the pin of the snap-fit connector. A combined parameter is proposed to capture the relationship between the investigated geometric properties and the stress concentration factor at the SRG. It is established that the fillet radius could indeed be used to offset the drop in performance associated with increasing the SRG depth while improving the fatigue characteristics of the connector threads.

Yoshiyuki Kondo - One of the best experts on this subject based on the ideXlab platform.

  • Effect of stress Relief Groove on fretting fatigue strength and index for the selection of optimal Groove shape
    International Journal of Fatigue, 2009
    Co-Authors: Masanobu Kubota, Shunsuke Kataoka, Yoshiyuki Kondo
    Abstract:

    Abstract The applicability of small stress Relief Groove for the improvement of fretting fatigue strength was studied. Fretting fatigue tests were done using several kinds of Grooved specimens. The shape of Groove was systematically changed with parameters of Groove radius R and tangential angle θ. The improvement of fatigue limit by a stress Relief Groove depended on both R and θ. The fretting fatigue limit with stress Relief Groove was increased with the increase of R and θ. The parameter θd (d: Groove depth) was selected for the unified evaluation of the improvement. FEM stress analyses were done to investigate the stress condition. In a simple elastic FEM analysis assuming that the contact edge is ideally shaped, a highly compressive stress field was generated near the contact edge, where small cracks could never propagate. This suggested that such a simple analysis was not enough to solve this problem. Thus, an assumption to relieve the highly compressive contact pressure near the contact edge was introduced to explain the experimental fact that a crack could propagate. The profile change was simulated by the local plastic deformation at the contact edge calculated by elasto-plastic FEM deformation analysis. This deformation reduced the highly compressive contact pressure and enabled the crack propagation. As a result, it was found that fretting fatigue limit of Grooved specimen could be evaluated on the basis of the maximum axial stress near the contact edge. The estimation of fretting fatigue limit using a relationship between Kt/Kt0 and θd provided a good estimation with the experimental results and it would be a useful method to select the optimal Groove shape.

  • Effect of stress Relief Groove shape on fretting fatigue strength and index for the selection of Groove shape
    Journal of the Society of Materials Science Japan, 2007
    Co-Authors: Yoshiyuki Kondo, Masanobu Kubota, Shunsuke Kataoka, Chu Sakae
    Abstract:

    Stress Relief Groove has been used to improve the fretting fatigue strength of fitted part between mechanical components. However, the effect of Groove has not been fully understood and there are not enough investigations to determine the optimal Groove shape. In this study, the evaluation of fretting fatigue strength of specimens which have various shapes of stress Relief Groove was conducted by fretting fatigue tests and FEM analyses in order to find an index for the selection of Groove shape. The Groove shape was changed systematically with parameters of Groove radius R and tangential angle θ. In the fretting fatigue test, fatigue limit of Grooved specimen had a peak with increase of θ. The maximum improvement of fatigue limit was achieved at the transition point of the failure mode from the fretting fatigue at contact part to the fatigue at Groove root. It was experimentally shown that fatigue limit had a good correlation with the parameter θd, where d is the Groove depth. FEM analyses were done to understand the effect of stress Relief Groove. It was found that the fretting fatigue limit of Grooved specimen could be evaluated using the peak axial stress near the contact edge. The estimation of fretting fatigue limit using a relationship between Kt/Kt0 and θd gave a good correlation with the experimental results and it would be a useful method to select the optimal Groove shape.

  • Effect of stress Relief Groove shape on fretting fatigue strength
    Key Engineering Materials, 2007
    Co-Authors: Shunsuke Kataoka, Masanobu Kubota, Chu Sakae, Yoshiyuki Kondo
    Abstract:

    The objective of this study is to evaluate the effect of stress Relief Groove on fretting fatigue strength. Fretting fatigue tests and finite element analyses were done. The shape of Groove was controlled by Groove radius R and tangential angle θ. The depth of Groove was specified by R and θ. Fretting fatigue strength was increased with an increase of θ and then it turned into a decrease. The decrease was caused by the transition of failure mode from fretting fatigue at the contact part to plain fatigue at the Groove root. The transition was caused by an increase of stress concentration at the Groove root with an increase of the Groove depth. Therefore, the maximum improvement of fatigue strength was achieved by the largest θ limited by fatigue strength of the Groove root. In the analysis, the Groove generates high compressive stress field at the contact edge, where small cracks never propagate. Therefore, assumptions to relieve the contact pressure concentration at the contact edge were taken into the analysis model. The values of stress intensity factor ranges for small cracks introduced near the contact edge were almost the same between Grooved and non-Groove specimens.

Shengyang Zhu - One of the best experts on this subject based on the ideXlab platform.

  • Fretting wear and fatigue in press-fitted railway axle: A simulation study of the influence of stress Relief Groove
    International Journal of Fatigue, 2019
    Co-Authors: Dongfang Zeng, Y. Zhang, Lang Zou, Shengyang Zhu
    Abstract:

    Abstract In this paper, a finite element model for the prediction of fretting fatigue crack initiation in the full-scale railway axle was proposed, which took into account the influence of the stress redistribution due to fretting wear on the fretting fatigue. Then, this model was used to investigate the influence of stress Relief Groove on the fretting wear and fatigue of the railway axle. The simulation results show that the stress concentration at the contact edge is gradually relieved with an increase in fretting cycles due to the fretting wear, while a new stress concentration appears at the edge of fretting wear scar, which gradually increases and moves towards the inner side of the contact area. The stress concentration in the inner side is considered to cause the fatigue crack initiation. Either the increase in Groove depth or the decrease in Groove radius can reduce the fretting wear and improve the fretting fatigue strength through relieving the stress concentration. Accompanying the improvement of fretting fatigue strength, the potential site of crack initiation gradually moves towards the contact edge. The simulation results stated above agree with the published experimental results.

Diego Erena - One of the best experts on this subject based on the ideXlab platform.

  • Numerical study on the influence of artificial internal stress Relief Groove on fretting fatigue in a shrink-fitted assembly
    Tribology International, 2020
    Co-Authors: Diego Erena, J. Vázquez, C. Navarro, Reza Hojjati Talemi
    Abstract:

    Abstract Fretting fatigue failure occurs in shrink-fitted assemblies due to the combination of high stresses and relative displacements near the contact edge. Due to these high stresses, fatigue crack initiates followed by crack propagation until final rupture. Additive manufacturing (AM) is a game changing technology, which enables new component capabilities that cannot be manufactured with conventional techniques. This research work analyses numerically the influence of an artificial internal stress Relief toroidal Groove inside a shrink-fitted shaft, which could be manufactured using AM technology. Due to the toroidal void, the stress/strain fields are redistributed improving the fretting fatigue crack initiation and propagation lifetimes. To do so, 2D finite element models are created in Abaqus software with and without the internal Groove. To estimate the fretting fatigue initiation and propagation lifetime and crack propagation direction, critical plane methods are used. In terms of the crack propagation, eXtended Finite Element Method (XFEM) is used to simulate mixed mode crack advancing in a single mesh structure. Finally, the obtained results with and without void were compared concluding with significant improvements in terms of total fatigue lifetime.