Reliability analysis of a hydraulic on/off fast switching valve

Niels Christian Bender, Henrik Clemmensen Pedersen, Andreas Plöckinger, Bernd Winkler

Research output: Contribution to book/anthology/report/conference proceedingArticle in proceedingResearch

Abstract

This paper presents an analysis of a hydraulic on/off valve from a reliability point of view. The objective is to clarify the potential pitfalls of the current valve design, while identifying the component(s) exerting the most significant risk of failure during the lifetime of the valve. Specifically, the mechanical topology of Fast Switching hydraulic Valves (FSVs) are of interest since these undergo operating cycles in the gigacycle regime in theirs functional lifetime. Application of these FSVs is relevant in e.g. digital displacement units, which for the specific design considered, experience pressure differentials of 345 bar at flow rates of 120 L/min and impact velocities around 1 m/s. All of which introduce a concern about the severity of long term fatigue and wear. Answers to these concerns are sought by first establishing a fault tree analysis of the FSV. Hereafter, the failure rates of different components are elaborated and expressions for such failure rates are established. This is done by a pseudo-analytic approach, where the expected reliability of the FSV is based upon statistical data. Results of two different cases are highlighted, namely failure with a low and high allowed internal leakage across the valve seat (0.0005 and 0.5 L/min). The study shows that the probability of a low leakage failure is close to 100% before 5 years of operation and 10% risk of high leakage failure after 25 years of operation. Valve seat failure is therefore a potential threat to limit the functional lifetime of the FSV. The applied reliability models involve a high amount of uncertainty, but there is a clear indication that failures will evolve around the flow passage. Allowing additional leakage prolongs the expected lifetime, and further work involves design of a framework to simulate design factors influencing the valves performance and lifetime.
Original languageEnglish
Title of host publicationProceedings of 9th Workshop on Digital Fluid Power, DFP 2017
Number of pages18
PublisherDepartment of Energy Technology, Aalborg University
Publication dateSep 2017
Publication statusPublished - Sep 2017
Event9th Workshop on Digital Fluid Power, DFP 2017 - Aalborg, Denmark
Duration: 7 Sep 20178 Sep 2017

Conference

Conference9th Workshop on Digital Fluid Power, DFP 2017
CountryDenmark
CityAalborg
Period07/09/201708/09/2017

Fingerprint

Reliability analysis
Hydraulics
Fault tree analysis
Flow rate
Topology
Wear of materials
Fatigue of materials

Keywords

  • Digital hydraulic valves
  • Failure mode analysis
  • Failure rate
  • Reliability

Cite this

Bender, N. C., Pedersen, H. C., Plöckinger, A., & Winkler, B. (2017). Reliability analysis of a hydraulic on/off fast switching valve. In Proceedings of 9th Workshop on Digital Fluid Power, DFP 2017 Department of Energy Technology, Aalborg University.
Bender, Niels Christian ; Pedersen, Henrik Clemmensen ; Plöckinger, Andreas ; Winkler, Bernd. / Reliability analysis of a hydraulic on/off fast switching valve. Proceedings of 9th Workshop on Digital Fluid Power, DFP 2017. Department of Energy Technology, Aalborg University, 2017.
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title = "Reliability analysis of a hydraulic on/off fast switching valve",
abstract = "This paper presents an analysis of a hydraulic on/off valve from a reliability point of view. The objective is to clarify the potential pitfalls of the current valve design, while identifying the component(s) exerting the most significant risk of failure during the lifetime of the valve. Specifically, the mechanical topology of Fast Switching hydraulic Valves (FSVs) are of interest since these undergo operating cycles in the gigacycle regime in theirs functional lifetime. Application of these FSVs is relevant in e.g. digital displacement units, which for the specific design considered, experience pressure differentials of 345 bar at flow rates of 120 L/min and impact velocities around 1 m/s. All of which introduce a concern about the severity of long term fatigue and wear. Answers to these concerns are sought by first establishing a fault tree analysis of the FSV. Hereafter, the failure rates of different components are elaborated and expressions for such failure rates are established. This is done by a pseudo-analytic approach, where the expected reliability of the FSV is based upon statistical data. Results of two different cases are highlighted, namely failure with a low and high allowed internal leakage across the valve seat (0.0005 and 0.5 L/min). The study shows that the probability of a low leakage failure is close to 100{\%} before 5 years of operation and 10{\%} risk of high leakage failure after 25 years of operation. Valve seat failure is therefore a potential threat to limit the functional lifetime of the FSV. The applied reliability models involve a high amount of uncertainty, but there is a clear indication that failures will evolve around the flow passage. Allowing additional leakage prolongs the expected lifetime, and further work involves design of a framework to simulate design factors influencing the valves performance and lifetime.",
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Bender, NC, Pedersen, HC, Plöckinger, A & Winkler, B 2017, Reliability analysis of a hydraulic on/off fast switching valve. in Proceedings of 9th Workshop on Digital Fluid Power, DFP 2017. Department of Energy Technology, Aalborg University, 9th Workshop on Digital Fluid Power, DFP 2017, Aalborg, Denmark, 07/09/2017.

Reliability analysis of a hydraulic on/off fast switching valve. / Bender, Niels Christian; Pedersen, Henrik Clemmensen; Plöckinger, Andreas; Winkler, Bernd.

Proceedings of 9th Workshop on Digital Fluid Power, DFP 2017. Department of Energy Technology, Aalborg University, 2017.

Research output: Contribution to book/anthology/report/conference proceedingArticle in proceedingResearch

TY - GEN

T1 - Reliability analysis of a hydraulic on/off fast switching valve

AU - Bender, Niels Christian

AU - Pedersen, Henrik Clemmensen

AU - Plöckinger, Andreas

AU - Winkler, Bernd

PY - 2017/9

Y1 - 2017/9

N2 - This paper presents an analysis of a hydraulic on/off valve from a reliability point of view. The objective is to clarify the potential pitfalls of the current valve design, while identifying the component(s) exerting the most significant risk of failure during the lifetime of the valve. Specifically, the mechanical topology of Fast Switching hydraulic Valves (FSVs) are of interest since these undergo operating cycles in the gigacycle regime in theirs functional lifetime. Application of these FSVs is relevant in e.g. digital displacement units, which for the specific design considered, experience pressure differentials of 345 bar at flow rates of 120 L/min and impact velocities around 1 m/s. All of which introduce a concern about the severity of long term fatigue and wear. Answers to these concerns are sought by first establishing a fault tree analysis of the FSV. Hereafter, the failure rates of different components are elaborated and expressions for such failure rates are established. This is done by a pseudo-analytic approach, where the expected reliability of the FSV is based upon statistical data. Results of two different cases are highlighted, namely failure with a low and high allowed internal leakage across the valve seat (0.0005 and 0.5 L/min). The study shows that the probability of a low leakage failure is close to 100% before 5 years of operation and 10% risk of high leakage failure after 25 years of operation. Valve seat failure is therefore a potential threat to limit the functional lifetime of the FSV. The applied reliability models involve a high amount of uncertainty, but there is a clear indication that failures will evolve around the flow passage. Allowing additional leakage prolongs the expected lifetime, and further work involves design of a framework to simulate design factors influencing the valves performance and lifetime.

AB - This paper presents an analysis of a hydraulic on/off valve from a reliability point of view. The objective is to clarify the potential pitfalls of the current valve design, while identifying the component(s) exerting the most significant risk of failure during the lifetime of the valve. Specifically, the mechanical topology of Fast Switching hydraulic Valves (FSVs) are of interest since these undergo operating cycles in the gigacycle regime in theirs functional lifetime. Application of these FSVs is relevant in e.g. digital displacement units, which for the specific design considered, experience pressure differentials of 345 bar at flow rates of 120 L/min and impact velocities around 1 m/s. All of which introduce a concern about the severity of long term fatigue and wear. Answers to these concerns are sought by first establishing a fault tree analysis of the FSV. Hereafter, the failure rates of different components are elaborated and expressions for such failure rates are established. This is done by a pseudo-analytic approach, where the expected reliability of the FSV is based upon statistical data. Results of two different cases are highlighted, namely failure with a low and high allowed internal leakage across the valve seat (0.0005 and 0.5 L/min). The study shows that the probability of a low leakage failure is close to 100% before 5 years of operation and 10% risk of high leakage failure after 25 years of operation. Valve seat failure is therefore a potential threat to limit the functional lifetime of the FSV. The applied reliability models involve a high amount of uncertainty, but there is a clear indication that failures will evolve around the flow passage. Allowing additional leakage prolongs the expected lifetime, and further work involves design of a framework to simulate design factors influencing the valves performance and lifetime.

KW - Digital hydraulic valves

KW - Failure mode analysis

KW - Failure rate

KW - Reliability

M3 - Article in proceeding

BT - Proceedings of 9th Workshop on Digital Fluid Power, DFP 2017

PB - Department of Energy Technology, Aalborg University

ER -

Bender NC, Pedersen HC, Plöckinger A, Winkler B. Reliability analysis of a hydraulic on/off fast switching valve. In Proceedings of 9th Workshop on Digital Fluid Power, DFP 2017. Department of Energy Technology, Aalborg University. 2017