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Krzysztof Siczek - One of the best experts on this subject based on the ideXlab platform.

  • Friction Resistance between Valve Made of TiAl Alloy and its Guide Made of Phosphor Bronze
    Applied Mechanics and Materials, 2013
    Co-Authors: Adam Rylski, Krzysztof Siczek
    Abstract:

    A Lightweight Valve is often made of TiAl alloys and its stem can be solid or hollow. Such Valves can mate with guides made of cast iron or of phosphor bronze at different conditions in their contact zone Valve/quide. The aim of the research was to measure the friction force in the sliding contact between the Valve stem made of TiAl alloy and its guide made of phosphor bronze, in the absence of oil. The experiment was conducted at room temperature and in static air under normal pressure. The investigations were conducted with use of the tester, which is presented in this article. The loading of contact zone has varied periodically during series. The displacement and acceleration of Valve and the force during its impact into seat insert have been measured during tests. Additionally the sound level has been measured, either. Tests have been provided for different frequency of driving force. Additionally, researches on the tribotester pin-on-disc, presented in the article, have been provided, with the pin made of Ti6Al4V alloy and the disc made of phosphor bronze. The model of research stand has been elaborated for the simulation of dynamics for the material sample rotating plate assembly. The aim of such researches has been to obtain values of coefficient of friction for such tribological pair and to simulate dynamics of the material sample rotating plate assembly, characteristic for used research stand. The obtained courses of coefficient of friction vs. loading, slide velocity, duration of motion of material sample in respect to the rotating plate have been presented in the article. On the base of simulation results the values of damping coefficient have been estimated, which allow to obtain the value for the amplitude of the modeled motion for the material sample in respect to the rotating plate near to the value of the amplitude for the real motion. Such estimation allows forecasting the dynamics of the mentioned assembly for other values of velocity and loading.

Adam Rylski - One of the best experts on this subject based on the ideXlab platform.

  • Friction Resistance between Valve Made of TiAl Alloy and its Guide Made of Phosphor Bronze
    Applied Mechanics and Materials, 2013
    Co-Authors: Adam Rylski, Krzysztof Siczek
    Abstract:

    A Lightweight Valve is often made of TiAl alloys and its stem can be solid or hollow. Such Valves can mate with guides made of cast iron or of phosphor bronze at different conditions in their contact zone Valve/quide. The aim of the research was to measure the friction force in the sliding contact between the Valve stem made of TiAl alloy and its guide made of phosphor bronze, in the absence of oil. The experiment was conducted at room temperature and in static air under normal pressure. The investigations were conducted with use of the tester, which is presented in this article. The loading of contact zone has varied periodically during series. The displacement and acceleration of Valve and the force during its impact into seat insert have been measured during tests. Additionally the sound level has been measured, either. Tests have been provided for different frequency of driving force. Additionally, researches on the tribotester pin-on-disc, presented in the article, have been provided, with the pin made of Ti6Al4V alloy and the disc made of phosphor bronze. The model of research stand has been elaborated for the simulation of dynamics for the material sample rotating plate assembly. The aim of such researches has been to obtain values of coefficient of friction for such tribological pair and to simulate dynamics of the material sample rotating plate assembly, characteristic for used research stand. The obtained courses of coefficient of friction vs. loading, slide velocity, duration of motion of material sample in respect to the rotating plate have been presented in the article. On the base of simulation results the values of damping coefficient have been estimated, which allow to obtain the value for the amplitude of the modeled motion for the material sample in respect to the rotating plate near to the value of the amplitude for the real motion. Such estimation allows forecasting the dynamics of the mentioned assembly for other values of velocity and loading.

Frank N Burgy - One of the best experts on this subject based on the ideXlab platform.

  • Lightweight Valve closes duct quickly
    NASA Tech Briefs, 1991
    Co-Authors: Walter L Fournier, Frank N Burgy
    Abstract:

    Expanding balloon serves as Lightweight emergency Valve to close wide duct. Uninflated balloon stored in housing of duct. Pad resting on burst diaphragm protects balloon from hot gases in duct. Once control system triggers Valve, balloon inflates rapidly to block duct. Weighs much less than does conventional butterfly, hot-gas, or poppet Valve capable of closing duct of equal diameter.

Walter L Fournier - One of the best experts on this subject based on the ideXlab platform.

  • Lightweight Valve closes duct quickly
    NASA Tech Briefs, 1991
    Co-Authors: Walter L Fournier, Frank N Burgy
    Abstract:

    Expanding balloon serves as Lightweight emergency Valve to close wide duct. Uninflated balloon stored in housing of duct. Pad resting on burst diaphragm protects balloon from hot gases in duct. Once control system triggers Valve, balloon inflates rapidly to block duct. Weighs much less than does conventional butterfly, hot-gas, or poppet Valve capable of closing duct of equal diameter.

Jeremy Trethewey - One of the best experts on this subject based on the ideXlab platform.

  • reliability of high temperature Lightweight Valve train components in a total probabilistic design environment
    Mechanical Properties and Performance of Engineering Ceramics II: Ceramic Engineering and Science Proceedings Volume 27 Issue 2, 2008
    Co-Authors: Osama M Jadaan, Jeremy Trethewey
    Abstract:

    Designing brittle material components to sustain transient structural loads without failing requires the use of a probabilistic design methodology. In the standard probabilistic treatment for ceramics, strength is assumed to be the sole stochastic parameter. However, variation in other parameters such as geometric dimensions, materials, and service load histories also exist and should be considered when evaluating the total probability of failure. Each of these parameter variations can cause changes in the stress state, which will in turn affect the probability of failure. The NASA CARES/Life code has been updated to interface with the ANSYS finite element analysis (FEA) Probabilistic Design System (PDS) in order to assess the total probability of failure for a given system. Hence the objectives of this work are: 1) Perform time dependent reliability analysis for a silicon nitride ceramic Valve subjected to an actual diesel engine cyclic thermomechanical load history, and 2) demonstrate the capability and value of the total probabilistic design approach in designing ceramic structures. Results indicate that the silicon nitride Valves are extremely reliable even after very long service lives. Results of the PDS analysis illustrate that the probability of failure is not a single value, as defined by the traditional probabilistic analysis for ceramics, but a range spanning several orders of magnitude. In addition, the PDS sensitivity analysis is demonstrated to identify which parameters have the maximum effect on the Valves' probability of failure (sensitivity plots) for efficient focus of resources.