Determining Stress in Turbocharger Impellers due to Component Machining Process

Simon Barrans, Md Shams E Tabriz, Christian Ellis

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

Turbocharger impeller wheels are traditionally manufactured using a casting process. However, with the improvement of multi-axial machining technology, machined impeller wheels are becoming popular among turbo machinery manufacturers due to their enhanced durability. Nonetheless, machining a complex impeller shape from a solid billet, results in tool marks being left on the component surface. As presented in this paper, repeatedly running a wheel to 5% beyond the design speed limit can result in fatigue failure initiating from the machining marks.

In this paper, the ‘as machined’ geometry of sample wheels has been determined using both CT scanning and optical surface measurement techniques. The data from these measurements has been used to generate solid CAD models suitable for finite element analysis to simulate the stress distribution of reverse engineered wheels. The maximum principal stress predicted is 15% higher than that obtained from the nominal CAD model. In order to model the measured geometry efficiently, a novel technique has been used to enforce cyclic symmetry on geometry that is not precisely cyclically symmetric.

The work has demonstrated that it is possible to predict the stress raising effect of the machining marks at the design stage. The analysis methodology presented in the paper will enable future integrated optimisation of both the design and manufacture of impeller wheels to ensure that wheels with a specified operating envelope are machined as efficiently as possible.
Original languageEnglish
Title of host publicationASME Turbo Expo 2017
Subtitle of host publicationTurbomachinery Technical Conference and Exposition
PublisherAmerican Society of Mechanical Engineers (ASME)
Number of pages11
VolumeVolume 7A: Structures and Dynamics
ISBN (Print)9780791850923
DOIs
Publication statusPublished - 2017
EventAmerican Society of Engineers Turbo-Expo: Turbomachinery Technical Conference & Exposition - Charlotte, United States
Duration: 26 Jun 201730 Jun 2017

Conference

ConferenceAmerican Society of Engineers Turbo-Expo
Abbreviated titleASME
CountryUnited States
CityCharlotte
Period26/06/1730/06/17

Fingerprint

Impellers
Wheels
Machining
Geometry
Computer aided design
Surface measurement
Machinery
Stress concentration
Casting
Durability
Fatigue of materials
Scanning
Finite element method

Cite this

Barrans, S., Tabriz, M. S. E., & Ellis, C. (2017). Determining Stress in Turbocharger Impellers due to Component Machining Process. In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition (Vol. Volume 7A: Structures and Dynamics). [V07AT30A006] American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/GT2017-64412
Barrans, Simon ; Tabriz, Md Shams E ; Ellis, Christian. / Determining Stress in Turbocharger Impellers due to Component Machining Process. ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. Vol. Volume 7A: Structures and Dynamics American Society of Mechanical Engineers (ASME), 2017.
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title = "Determining Stress in Turbocharger Impellers due to Component Machining Process",
abstract = "Turbocharger impeller wheels are traditionally manufactured using a casting process. However, with the improvement of multi-axial machining technology, machined impeller wheels are becoming popular among turbo machinery manufacturers due to their enhanced durability. Nonetheless, machining a complex impeller shape from a solid billet, results in tool marks being left on the component surface. As presented in this paper, repeatedly running a wheel to 5{\%} beyond the design speed limit can result in fatigue failure initiating from the machining marks. In this paper, the ‘as machined’ geometry of sample wheels has been determined using both CT scanning and optical surface measurement techniques. The data from these measurements has been used to generate solid CAD models suitable for finite element analysis to simulate the stress distribution of reverse engineered wheels. The maximum principal stress predicted is 15{\%} higher than that obtained from the nominal CAD model. In order to model the measured geometry efficiently, a novel technique has been used to enforce cyclic symmetry on geometry that is not precisely cyclically symmetric. The work has demonstrated that it is possible to predict the stress raising effect of the machining marks at the design stage. The analysis methodology presented in the paper will enable future integrated optimisation of both the design and manufacture of impeller wheels to ensure that wheels with a specified operating envelope are machined as efficiently as possible.",
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Barrans, S, Tabriz, MSE & Ellis, C 2017, Determining Stress in Turbocharger Impellers due to Component Machining Process. in ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. vol. Volume 7A: Structures and Dynamics, V07AT30A006, American Society of Mechanical Engineers (ASME), American Society of Engineers Turbo-Expo, Charlotte, United States, 26/06/17. https://doi.org/10.1115/GT2017-64412

Determining Stress in Turbocharger Impellers due to Component Machining Process. / Barrans, Simon; Tabriz, Md Shams E; Ellis, Christian.

ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. Vol. Volume 7A: Structures and Dynamics American Society of Mechanical Engineers (ASME), 2017. V07AT30A006.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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T1 - Determining Stress in Turbocharger Impellers due to Component Machining Process

AU - Barrans, Simon

AU - Tabriz, Md Shams E

AU - Ellis, Christian

N1 - Accepted date from ePrints SH.

PY - 2017

Y1 - 2017

N2 - Turbocharger impeller wheels are traditionally manufactured using a casting process. However, with the improvement of multi-axial machining technology, machined impeller wheels are becoming popular among turbo machinery manufacturers due to their enhanced durability. Nonetheless, machining a complex impeller shape from a solid billet, results in tool marks being left on the component surface. As presented in this paper, repeatedly running a wheel to 5% beyond the design speed limit can result in fatigue failure initiating from the machining marks. In this paper, the ‘as machined’ geometry of sample wheels has been determined using both CT scanning and optical surface measurement techniques. The data from these measurements has been used to generate solid CAD models suitable for finite element analysis to simulate the stress distribution of reverse engineered wheels. The maximum principal stress predicted is 15% higher than that obtained from the nominal CAD model. In order to model the measured geometry efficiently, a novel technique has been used to enforce cyclic symmetry on geometry that is not precisely cyclically symmetric. The work has demonstrated that it is possible to predict the stress raising effect of the machining marks at the design stage. The analysis methodology presented in the paper will enable future integrated optimisation of both the design and manufacture of impeller wheels to ensure that wheels with a specified operating envelope are machined as efficiently as possible.

AB - Turbocharger impeller wheels are traditionally manufactured using a casting process. However, with the improvement of multi-axial machining technology, machined impeller wheels are becoming popular among turbo machinery manufacturers due to their enhanced durability. Nonetheless, machining a complex impeller shape from a solid billet, results in tool marks being left on the component surface. As presented in this paper, repeatedly running a wheel to 5% beyond the design speed limit can result in fatigue failure initiating from the machining marks. In this paper, the ‘as machined’ geometry of sample wheels has been determined using both CT scanning and optical surface measurement techniques. The data from these measurements has been used to generate solid CAD models suitable for finite element analysis to simulate the stress distribution of reverse engineered wheels. The maximum principal stress predicted is 15% higher than that obtained from the nominal CAD model. In order to model the measured geometry efficiently, a novel technique has been used to enforce cyclic symmetry on geometry that is not precisely cyclically symmetric. The work has demonstrated that it is possible to predict the stress raising effect of the machining marks at the design stage. The analysis methodology presented in the paper will enable future integrated optimisation of both the design and manufacture of impeller wheels to ensure that wheels with a specified operating envelope are machined as efficiently as possible.

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DO - 10.1115/GT2017-64412

M3 - Conference contribution

SN - 9780791850923

VL - Volume 7A: Structures and Dynamics

BT - ASME Turbo Expo 2017

PB - American Society of Mechanical Engineers (ASME)

ER -

Barrans S, Tabriz MSE, Ellis C. Determining Stress in Turbocharger Impellers due to Component Machining Process. In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. Vol. Volume 7A: Structures and Dynamics. American Society of Mechanical Engineers (ASME). 2017. V07AT30A006 https://doi.org/10.1115/GT2017-64412