Utilizing Dynamic Fuel Pressure Sensor For Detecting Bearing Spalling and Gear Pump Failure Modes in Cummins Pressure Time ( PT ) Pumps
The objective of this paper is to highlight the results of the fault detection investigation conducted to ascertain the feasibility of exploiting the existing on-board M2/M3 Bradley fuel pressure sensor for the purpose of detecting mechanical bearing spalling and gear pump failure modes of the pressure-time (PT) fuel pump used on the Cummins VTA-903T engine. To investigate this fluid-mechanical cross domain detection approach, a Bradley fuel system test bed was built. Fault tests for four PT pump failure modes were conducted including bearing faults, gear pump fault, idle adjust mis-calibration, and air-fuel control fault. The results of the first two fault tests are summarized in this paper. Due to limited number of pumps available for testing (2), these preliminary findings are not statistically substantiated. With this stated, the findings present a method for investigating the presence of a narrowband frequency-domain-based predictive fault detection capability using the existing pressure sensor installed on the Chassis Modernization and Embedded Diagnostics (CMED) variant Bradley. The test stand based seeded fault analysis was not capable of detecting an 0.080 inch outer raceway bearing spall, but there is preliminary evidence to warrant further study that a nominal 0.001 inch foreign object debris accumulation on the gear teeth of the gear pump might be detectable using a simple kurtosis based calculation using a pressure sensor with a 0-500 Hz dynamic bandwidth.
Platform degrader analysis for the design and development of Vehicle Health Management Systems
The US Armypsilas Heavy Brigade Combat Team (HBCT) is investigating the implementation of Vehicle Health Management Systems across its fleet of platforms. A vehicle degrader analysis was conducted to determine where the application of vehicle health management systems (VHMS) could potentially have the greatest impact on increasing maintainer effectiveness and operational availability. The analysis was conducted for M1 Abrams tanks and M2/M3 Bradley Fighting Vehicles using data from three sources: (1) multi-year statistical data on repairs, operating and support costs, and logistics data, (2) interviews with maintainers, service representatives and operators, and (3) questionnaires completed by the platform OEMpsilas. The paper will describe how these alternative data and information sources were used when ideal data and information sources were not available. The statistical data provided an indication of vehicle consumable and repairable cost drivers, part replacement quantity and some indication of component failure isolation for vehicle systems. The interviews with vehicle maintainers, field service representatives and operators provided insight into platform reliability, maintainability and human factors issues. The maintainability, reliability and diagnostic coverage information from the OEMpsilas, provided information about mission criticality and general diagnostic capability for specific vehicle sub-systems and components. The results of the degrader analysis include a list of components and sub-systems that contribute most to maintainability, reliability and vehicle operational availability issues. The degrader results, were used to develop the conceptual design of the optimum application of embedded vehicle diagnostics and prognostics for more effective and efficient HCBT platform maintenance, logistic support and platform life cycle management.
Frequency selective surface design for blinds applications
In this paper, the reconfigurable blind structure with frequency selective surfaces(FSS) for the building applications are presented. Frequency transmission characteristics for different angles of the proposed blind-FSSs are investigated and verified through simulation and measurement. The simulation results show that we can implement the reconfigurable blind-FSS for multiband wireless applications. To verify the proposed paper, two kinds of blind-FSSs, crossed dipole FSS and circular ring FSS are fabricated and measurements are performed for different angles. The proposed structure in this paper which is very simple, can be easily applied to any planar surface for wireless security applications at low cost.