The main failure cause of PTFE lip-seals is abrasive wear of the sealing edge or sealing lip. The failure of sealing elements is unwanted for various reasons. On the one hand the leak of fluid to be sealed can have negative influences on environment. On the other hand the leak of fluid acting as lubrication can lead to the damage or to the failure of an entire machine or plant. Ecological and economic aspects become more and more important for the use of machines and plants. The unexpected shutdown caused by failure of the seal is to be avoided under all circumstances. Therefore one wants to know the wear characteristics of the sealing element under the given operating conditions. Reaching a high lifetime is the highest goal for the development of sealing systems. So maintenance costs can be minimised. Prediction of the achievable lifetime regarding operation conditions is a further important point for the use of sealing elements. For mentioned reasons an early replacement of the seal can be reasonable.
Describing wear characteristics of PTFE lip-seals is the intention of the actual thesis. One aim of this study was the programming of a tool, which is able to simulate wear. In order to illustrate the change of the component due to wear correctly, wear characteristics must be described by a wear model. For this on the one hand the selection of a suitable wear model is necessary. On the other hand extensive experimental investigations are required to get the appropriate parameters for the selected wear model. Various tribological tests were passed to determine the specific wear characteristics of a PTFE-compound which is in common use for lip-seals. Final analyses compare the simulation results with PTFE lip-seals after endurance tests.
The investigations to the wear of PTFE-compounds, accomplished in the context of this thesis, and the developed tools for numeric wear simulation make an important contribution to this part of the sealing technology. The results of the wear investigations give limitations for use of PTFE/carbon-compounds against steel surfaces. With attention to the determined limitations a low-wear application of the material is possible. The two presented methods of wear simulation show different ways for the implementation of the wear-conditioned volume reduction within FE-simulation. Both methods have their special shown pro and cons. A substantial success of this thesis is the objective evidence that wear simulation with characteristic values out of tribological tests has good results. The combination of these two methods was so far not used in the sealing technology in this form. In the past tribological tests were already accomplished for the determination of wear rates of certain combinations of material. There are already studies, which were concerned with wear simulation. Here the wear factor was verified in such way that the simulation results were fitted to the test results. However a transfer of the characteristic values is not possible on other components. In the context of this dissertation the wear factor was determined at the tribological test rig and transferred to wear simulation on PTFE lip-seals. It was proven that this transfer is possible and gives a good agreement with component tests.
Due to the large variance of the test results a concrete statement about reaching a certain operating time of one seal can not be made right now. Therefore further investigations will be necessary in the future. These may not only operate with the average values of the test results. More significant simulation results are expected in consideration of the distribution of the test results at the tribological test rig. However a higher number of test runs are necessary. This is not to be realised with only one test rig in limited time. Therefore a larger number of tribological tests should be passed parallel in future investigations. It must be examined if the variance of the results at the tribological test rig matches with the test results on PTFE lip-seals.
The methodology of wear simulation offers also further development potential. In order to make this tool for a broad user spectrum usable, the application must be arranged simpler. At last it should be integrated into existing FE-programs.
%0 Book
%1 Weber.2012
%A Weber, Dirk
%B Institutsbericht
%D 2012
%K from:thomasherzig dichtungstechnik D_Weber dissertation from:brunomueller from:samuelschwamm ima
%T Numerische Verschleißsimulation auf Basis tribologischer Untersuchungen am Beispiel von PTFE-Manschettendichtungen: Dissertation
%V Nr. 139
%X The main failure cause of PTFE lip-seals is abrasive wear of the sealing edge or sealing lip. The failure of sealing elements is unwanted for various reasons. On the one hand the leak of fluid to be sealed can have negative influences on environment. On the other hand the leak of fluid acting as lubrication can lead to the damage or to the failure of an entire machine or plant. Ecological and economic aspects become more and more important for the use of machines and plants. The unexpected shutdown caused by failure of the seal is to be avoided under all circumstances. Therefore one wants to know the wear characteristics of the sealing element under the given operating conditions. Reaching a high lifetime is the highest goal for the development of sealing systems. So maintenance costs can be minimised. Prediction of the achievable lifetime regarding operation conditions is a further important point for the use of sealing elements. For mentioned reasons an early replacement of the seal can be reasonable.
Describing wear characteristics of PTFE lip-seals is the intention of the actual thesis. One aim of this study was the programming of a tool, which is able to simulate wear. In order to illustrate the change of the component due to wear correctly, wear characteristics must be described by a wear model. For this on the one hand the selection of a suitable wear model is necessary. On the other hand extensive experimental investigations are required to get the appropriate parameters for the selected wear model. Various tribological tests were passed to determine the specific wear characteristics of a PTFE-compound which is in common use for lip-seals. Final analyses compare the simulation results with PTFE lip-seals after endurance tests.
The investigations to the wear of PTFE-compounds, accomplished in the context of this thesis, and the developed tools for numeric wear simulation make an important contribution to this part of the sealing technology. The results of the wear investigations give limitations for use of PTFE/carbon-compounds against steel surfaces. With attention to the determined limitations a low-wear application of the material is possible. The two presented methods of wear simulation show different ways for the implementation of the wear-conditioned volume reduction within FE-simulation. Both methods have their special shown pro and cons. A substantial success of this thesis is the objective evidence that wear simulation with characteristic values out of tribological tests has good results. The combination of these two methods was so far not used in the sealing technology in this form. In the past tribological tests were already accomplished for the determination of wear rates of certain combinations of material. There are already studies, which were concerned with wear simulation. Here the wear factor was verified in such way that the simulation results were fitted to the test results. However a transfer of the characteristic values is not possible on other components. In the context of this dissertation the wear factor was determined at the tribological test rig and transferred to wear simulation on PTFE lip-seals. It was proven that this transfer is possible and gives a good agreement with component tests.
Due to the large variance of the test results a concrete statement about reaching a certain operating time of one seal can not be made right now. Therefore further investigations will be necessary in the future. These may not only operate with the average values of the test results. More significant simulation results are expected in consideration of the distribution of the test results at the tribological test rig. However a higher number of test runs are necessary. This is not to be realised with only one test rig in limited time. Therefore a larger number of tribological tests should be passed parallel in future investigations. It must be examined if the variance of the results at the tribological test rig matches with the test results on PTFE lip-seals.
The methodology of wear simulation offers also further development potential. In order to make this tool for a broad user spectrum usable, the application must be arranged simpler. At last it should be integrated into existing FE-programs.
%@ 978-3-936100-40-2
@book{Weber.2012,
abstract = {The main failure cause of PTFE lip-seals is abrasive wear of the sealing edge or sealing lip. The failure of sealing elements is unwanted for various reasons. On the one hand the leak of fluid to be sealed can have negative influences on environment. On the other hand the leak of fluid acting as lubrication can lead to the damage or to the failure of an entire machine or plant. Ecological and economic aspects become more and more important for the use of machines and plants. The unexpected shutdown caused by failure of the seal is to be avoided under all circumstances. Therefore one wants to know the wear characteristics of the sealing element under the given operating conditions. Reaching a high lifetime is the highest goal for the development of sealing systems. So maintenance costs can be minimised. Prediction of the achievable lifetime regarding operation conditions is a further important point for the use of sealing elements. For mentioned reasons an early replacement of the seal can be reasonable.
Describing wear characteristics of PTFE lip-seals is the intention of the actual thesis. One aim of this study was the programming of a tool, which is able to simulate wear. In order to illustrate the change of the component due to wear correctly, wear characteristics must be described by a wear model. For this on the one hand the selection of a suitable wear model is necessary. On the other hand extensive experimental investigations are required to get the appropriate parameters for the selected wear model. Various tribological tests were passed to determine the specific wear characteristics of a PTFE-compound which is in common use for lip-seals. Final analyses compare the simulation results with PTFE lip-seals after endurance tests.
The investigations to the wear of PTFE-compounds, accomplished in the context of this thesis, and the developed tools for numeric wear simulation make an important contribution to this part of the sealing technology. The results of the wear investigations give limitations for use of PTFE/carbon-compounds against steel surfaces. With attention to the determined limitations a low-wear application of the material is possible. The two presented methods of wear simulation show different ways for the implementation of the wear-conditioned volume reduction within FE-simulation. Both methods have their special shown pro and cons. A substantial success of this thesis is the objective evidence that wear simulation with characteristic values out of tribological tests has good results. The combination of these two methods was so far not used in the sealing technology in this form. In the past tribological tests were already accomplished for the determination of wear rates of certain combinations of material. There are already studies, which were concerned with wear simulation. Here the wear factor was verified in such way that the simulation results were fitted to the test results. However a transfer of the characteristic values is not possible on other components. In the context of this dissertation the wear factor was determined at the tribological test rig and transferred to wear simulation on PTFE lip-seals. It was proven that this transfer is possible and gives a good agreement with component tests.
Due to the large variance of the test results a concrete statement about reaching a certain operating time of one seal can not be made right now. Therefore further investigations will be necessary in the future. These may not only operate with the average values of the test results. More significant simulation results are expected in consideration of the distribution of the test results at the tribological test rig. However a higher number of test runs are necessary. This is not to be realised with only one test rig in limited time. Therefore a larger number of tribological tests should be passed parallel in future investigations. It must be examined if the variance of the results at the tribological test rig matches with the test results on PTFE lip-seals.
The methodology of wear simulation offers also further development potential. In order to make this tool for a broad user spectrum usable, the application must be arranged simpler. At last it should be integrated into existing FE-programs.},
added-at = {2021-03-25T17:56:25.000+0100},
author = {Weber, Dirk},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2037150d862f6a29368cd580e4f920e4f/ima-publ},
institution = {Universität Stuttgart, Institut für Maschinenelemente},
interhash = {f4e0938cdc47c42a9b50d9bac3414495},
intrahash = {037150d862f6a29368cd580e4f920e4f},
isbn = {978-3-936100-40-2},
keywords = {from:thomasherzig dichtungstechnik D_Weber dissertation from:brunomueller from:samuelschwamm ima},
note = 480,
series = {Institutsbericht},
timestamp = {2021-03-25T16:56:25.000+0100},
title = {Numerische Verschleißsimulation auf Basis tribologischer Untersuchungen am Beispiel von PTFE-Manschettendichtungen: Dissertation},
volume = {Nr. 139},
year = 2012
}
