RAM analysis of dynamic positioning system: An approach taking into account uncertainties and criticality equipment ratings

Currently, a Dynamic Position (DP) System is commonly used for offshore operations. However, DP failures may generate environmental and economic losses; thus, this paper presents the Reliability, Availability and Maintainability (RAM) analysis for two different generations of DP system (DP2 and DP3) used in drilling operations. In addition to the RAM analysis, the approach proposed herein considers the uncertainties present in the equipment failure data and provides more information about criticality equipment ratings and probability density functions (pdf) of the repair times. The reliability analysis shows that, for 3 months of operation, the total failure probability of the DP2 system is 1.52% whereas this probability for the DP3 system is only 0.16%. The results reveal that the bus-bar is the most critical equipment of the DP2 system, whereas the wind sensor represents the priority equipment in the DP3 system. Using 90% confidence level, each DP configuration was evaluated for a 1-year operation, finding a reliability mean equal to 70.39% and 86.77% for the DP2 system and the DP3 system, respectively. The DP2 system asymptotic availability tends to present a constant value of 99.98% whereas for the DP3 system, it tends to be 99.99%. Finally, the maintainability analysis allows concluding that the mean time for system repair is expected to be 3.6 h. This paper presents a logical pathway for analysts, operators, and reliability engineers of the oil and gas industry.

Maintenance scheduling of a cheddar cheese manufacturing plant based on RAM analysis

PurposeThe purpose of this research is to calculate and enhance the cheese cheddar manufacturing plant efficiency under actual workplace conditions by measuring reliability, availability and maintainability (RAM) indices. The authors highlight how RAM analysis is important in determining periodic maintenance and in scheduling and managing the appropriate maintenance policy.Design/methodology/approachThe current work is conducted using statistical approaches to evaluate failure and repair statistics. The RAM estimation was calculated on the basis of quantitative data obtained over a span of 32 months. Descriptive statistics, Pareto analysis, as well as the presumption of independence were ensured through trend and serial correlation tests. In addition, the reliability and maintainability of the cheddar cheese processing plant and its machines were calculated at various mission periods.FindingsThe primary goal of the implementation approach is to understand the fault patterns and the accurate quantitative assessment of the reliability and maintainability of the cheddar production plant. The findings revealed the essential aspects of the line, which need improvement by an appropriate maintenance program.Originality/valueThis study is intended to serve to highlight the RAM assessment and its impact on the performance of the real-time system. The benefit of the technique is the continual control of the manufacturing process by means of acceptable indexes, whose use corresponds to a continuous improvement process.

Unmanned Platform Design Methodology

Remotely operated and unmanned facilities offer significant safety, environmental and economic benefits over conventional facilities. This paper describes the key elements for successful design and an approach for evaluating the reliability, availability and TOTEX of unmanned facilities. The approach was developed during the concept and FEED phases of a wellhead platform project and forms the basis of the unmanned strategy going forwards but can also be used for facilities with partial processing topsides. During the design of a recent platform it became clear that normal FMEA/RAM analysis was not suitable for assessing the reliability and availability of unmanned facilities with low visit frequency. Drawing on previous experience, a new approach was developed to address the specific challenges of low maintenance intervals and provide a methodical approach to proving reliability. The new approach improved confidence in the predicted availability by identifying key components and appropriate reliability data. The process adds some extra steps to typical reliability and availability assessment, which are designed to address the specific demands of unmanned operations. The result of this work has given a clearer understanding of how reliability can be assessed and managed for low-manned or unmanned applications. The methodology helps to identify unmanned /low manned opportunities and provides guidance on design and reliability assessment It is observed that system reliability is usually driven by a few key components and that whilst many components have good overall reliability data this may not be applicable for the proposed specific operating environment and maintenance regime of an unmanned platform. It is therefore essential to evaluate components individually for their specific applications. It is concluded that to achieve the unmanned goal it is vital to fully understand the system and component reliability early in the project. The proposed methodology can be applied at any stage to validate the design, confirm assumptions, or identify gaps.

An Approach to Reliability, Availability and Maintainability Analysis of a Plug-In Electric Vehicle

Electric vehicle technologies have seen rapid development in recent years. However, Reliability, Availability, and Maintainability (RAM) related concerns still have restricted large-scale commercial utilization of these vehicles. This paper presents an approach to carry out a quantitative RAM analysis of a plug-in electric vehicle. A mathematical model is developed in the Markov Framework incorporating the reliability characteristics of all significant electrical components of the vehicle system, namely battery, motor, drive, controllers, charging unit, and energy management unit. The study shows that the vehicle’s survivability can be increased by improving its components’ restoration rates. The paper also investigates the role of a charging station on the availability of the vehicle. It illustrates how the grid power supply’s reliability influences the operational effectiveness of a plug-in electric vehicle. The concepts that are presented in the article can support further study on the reliability design and maintenance of a plug-in electric vehicle.