A Time-Discontinuous Galerkin Finite Element Method for the Solution of Impact Problem of Gas-Saturated Coal

Zhang, Jingfei; Guo, Deyong; Wu, Wenhua; Guo, Pan

doi:10.1155/2020/8845056

Cited by 2 publications

(1 citation statement)

References 12 publications

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“…The pressing process is created by continuous press forming from a sheet roll source; the sheet used in the roll may not have a homogeneous thickness everywhere due to the production process for this reason. The thickness of the sheet metal parts in the package varies (Vondrous et al , 2015; Xue et al , 2003; Zhang et al , 2020). This situation causes the stator stack height to change.…”

Section: Resultsmentioning

confidence: 99%

Effect of stator height change on bearing life in aircraft autopilot servos

Ortamevzi

Şahin²

2022

AEAT

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Purpose The purpose of this paper is to make a more precise prediction of the life of servo motors used in aircraft. The variation of the axial load created by the wave washer for bearing, which is one of the factors affecting the bearing life of the electric motors and servo motors used in aircraft, was analyzed. Design/methodology/approach In electric motors and servo motors that body as stator, the height of the stator stack affects the compression amount of the wave washer spring. Working with electric motor and servo manufacturers, production-related variations in stator height were determined by making multiple measurements. The reaction forces resulting from these compression amounts were simulated by mathematical modeling with the finite element method, and also experimentally measured on real parts. Findings Results obtained with finite element method and real experiments were compared. By adding the force differences to the general operating conditions, the effect on the bearing life was theoretically determined. In a servo motor with this type of construction, the difference in stator height created different axial loads on the motor shaft. The difference of these loads affected the motor bearing life. Research limitations/implications The results implicated in terms of flight safety, maintenance operation and resource efficiency. Practical implications The results of this study are effective in determining the maintenance intervals more clearly. This study can be used for the design criteria of aircraft servo motors. These servos, which are especially used to move the flight control surfaces, contribute to flight safety as the life expectancy will be clearer. Social implications This study may be effective in preventing aviation accidents caused by servo motors. It can make maintenance management more efficient. Originality/value This study investigated the effect of aircraft servo motor design inputs on servo motor life, considering the production.

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Section: Resultsmentioning

confidence: 99%

Effect of stator height change on bearing life in aircraft autopilot servos

Ortamevzi

Şahin²

2022

AEAT

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Transient Acoustic Wave Propagation Problems in Multilayered Pavement Using a Time Discontinuous Galerkin Finite Element Method

Yue

Guo

2022

Applied Sciences

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This paper presents a modified time discontinuous Galerkin finite element method (MDGFEM) for transient acoustic wave propagation problem of multilayered pavement. The pavement consists of cement concrete pavement, semi-rigid base, and natural soil. The multilayered pavement is modeled as poroelastic mediums and assumed to be water-saturated. The well-known generalized Biot’s theory is employed to describe the wave propagation problem. The present MDGFEM, based on the artificial damping scheme, employs the Hermite (P3) functions and the linear (P1) shape functions to interpolate the global nodal vector and its temporal gradient respectively in a time step. Numerical results of 1D and 2D problems show that the MDGFEM can filter out spurious numerical oscillations before and after waves, boundaries of the hole, and the interface between the layers more effectively for the propagation of acoustic waves in multilayered pavement. Compared with widely used time-continuous methods such as the Newmark method, the method proposed in this paper presents better capabilities in the fluid–structure interaction behavior of multilayer pavements and provides a more accurate solution, which contributes to the further development of non-destructive testing of multilayer pavement structures.

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A Time-Discontinuous Galerkin Finite Element Method for the Solution of Impact Problem of Gas-Saturated Coal

Cited by 2 publications

References 12 publications

Effect of stator height change on bearing life in aircraft autopilot servos

Effect of stator height change on bearing life in aircraft autopilot servos

Transient Acoustic Wave Propagation Problems in Multilayered Pavement Using a Time Discontinuous Galerkin Finite Element Method

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