Prognostics and health management design for rotary machinery systems—Reviews, methodology and applications

A degradation path-dependent approach for remaining useful life estimation with an exact and closed-form solution

Fuel cell technology can be traced back to 1839 when British scientist Sir William Grove discovered that it was possible to generate electricity by the reaction between hydrogen and oxygen gases. However, fuel cell still cannot compete with internal combustion engines although they have many advantages including zero carbon emissions. Fossil fuels are cheaper and present very high volumetric energy densities compared with the hydrogen gas. Furthermore, hydrogen storage as a liquid is still a huge challenge. Another important disadvantage is the lifespan of the fuel cell because of their durability, reliability and maintainability. Prognostics is an emerging technology in sustainability of engineering systems through failure prevention, reliability assessment and remaining useful lifetime estimation. Prognostics and health monitoring can play a critical role in enhancing the durability, reliability and maintainability of the fuel cell system. This paper presents a review on the current state-of-the-art in prognostics and health monitoring of Proton Exchange Membrane Fuel Cell (PEMFC), aiming at identifying research and development opportunities in these fields. This paper also highlights the importance of incorporating prognostics and failure modes, mechanisms and effects analysis (FMMEA) in PEMFC to give them sustainable competitive advantage when compared with other non-clean energy solutions.

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A review on prognostics and health monitoring of proton exchange membrane fuel cell

Power electronics are efficient for conversion and conditioning of the electrical energy through a wide range of applications. Proper life consumption estimation methods applied for power electronics that can operate in real time under in-service mission profile conditions will not only provide an effective assessment of the products life expectancy but they can also deliver reliability design information. This is important to aid in manufacturing and thus helps in reducing costs and maximizing through-life availability. In this paper, a mission profile-based approach for real-time life consumption estimation which can be used for reliability design of power electronics is presented. The paper presents the use of electrothermal models coupled with physics-of-failure analysis by means of real-time counting algorithm to provide accurate life consumption estimations for power modules operating under in-service conditions. These models, when driven by the actual mission profiles, can be utilized to provide advanced warning of failures and thus deliver information that can be useful to meet particular application requirements for reliability at the design stage. To implement this approach, an example of two case studies using mission profiles of a metro-system and wind-turbines applications is presented.

https://nottingham-repository.worktribe.com/preview/740551/Mission%20profile-based%20reliability%20design%20and%20real-time%20life%20consumption%20estimation%20in%20power%20electronics.pdf

Mission Profile-Based Reliability Design and Real-Time Life Consumption Estimation in Power Electronics

The current state of the art in managing system reliability is geared toward the development of predictive models for unaged pristine materials. The current state of art allows the prediction of time-to-failure for a pristine material under known loading conditions based on relationships such as the Paris' power law , , the Coffin-Manson relationship [2], [13], [23], [24], and the S-N diagram. There is a need for methods and processes which will allow interrogation of material state in complex systems and subsystems to determine the remaining useful life prior to repair or replacement. This capability of determination of material or system state is called prognosis. In this paper, a methodology for prognostication of electronics has been demonstrated with data of leading indicators of failure for accurate assessment of product damage prior to appearance of any macro indicators of damage. Proxies for leading indicators of failure have been identified. Examples of proxies include microstructural evolution characterized by average phase size and correlated to time and equivalent creep strain rate, and stresses at interface of silicon structures. Structures examined include an electronics package and microelectromechanical systems package and interconnections. The test vehicle includes packages that have been mounted on a metal-backed printed circuit board typical of electronics deployed in harsh environments. In application environment, the metal backing provides thermal dissipation, mechanical stability, and interconnections reliability. Since an aged material knows its state, the research presented in this paper focuses on enhancing the understanding of material damage to facilitate proper interrogation of material state. A mathematical relationship has been developed between phase growth rate and time-to-1-percent failure to enable the computation of damage manifested and a forward estimate of residual life

Prognostics and Health Management of Electronic Packaging

Fine-pitch ball grid array (BGA) and underfills have been used in benign office environments and wireless applications for a number of years, however their reliability in automotive underhood environment is not well understood. In this work, the reliability of fine-pitch plastic ball grid array (PBGA) packages has been evaluated in the automotive underhood environment. Experimental studies indicate that the coefficient of thermal expansion (CTE) as measured by thermomechanical analyzer (TMA) typically starts to change at 10-15/spl deg/C lower temperature than the T/sub g/ specified by differential scanning calorimetry (DSC) potentially extending the change in CTE well into the accelerated test envelope in the neighborhood of 125/spl deg/C. High T/sub g/ substrates with glass-transition temperatures much higher than the 125/spl deg/C high temperature limit, are therefore not subject to the effect of high coefficient of thermal expansion close to the high temperature of the accelerated test. Darveaux's damage relationships were derived on ceramic ball grid array (CBGA) assemblies, with predominantly solder mask defined (SMD) pads and 62Sn36Pb2Ag solder. In addition to significant differences in the crack propagation paths for the two pad constructions, SMD pads fail significantly faster than the non solder mask defined (NSMD) pads in thermal fatigue. The thermal mismatch on CBGAs is much larger than PBGA assemblies. Crack propagation in CBGAs is often observed predominantly on the package side as opposed to both package and board side for PBGAs. In the present study, crack propagation data has been acquired on assemblies with 15, 17, and 23mm size plastic BGAs with NSMD pads and 63Sn37Pb on high-T/sub g/ printed circuit boards. The data has been benchmarked against Darveaux's data on CBGA assemblies. Experimental matrix also encompasses the effect of bis-maleimide triazine (BT) substrate thickness on reliability. Damage constants have been developed and compared against existing Darveaux Constants. Prediction error has been quantified for both sets of constants.

Model for BGA and CSP reliability in automotive underhood applications

Increased use of sensors and controls in automotive applications has resulted in significant emphasis on the deployment of electronics directly mounted on the engine and transmission. Increased shock, vibration, and higher temperatures necessitate the fundamental understanding of damage mechanisms which will be active in these environments. Electronics typical of office benign environments use FR-4 printed circuit boards (PCBs). Automotive applications typically use high glass-transition temperature laminates such as FR4-06 glass/epoxy laminate material (T/sub g/=164.9/spl deg/C). In automotive underhood application environments, metal-backing of PCBs is being targeted for thermal dissipation, mechanical stability, and interconnections reliability. In this study, the effect of metal-backed boards on the interconnect reliability has been evaluated. Previous studies on electronic reliability for automotive environments have addressed the damage mechanics of solder joints in plastic ball-grid arrays (BGAs) on nonmetal backed substrates and ceramic BGAs on nonmetal backed substrates. Other failure mechanisms investigated include delamination of PCB from metal backing. The test vehicle is a metal backed FR4-06 laminate. Metal backings investigated include aluminum and beryllium copper. Three adhesives have been investigated for metal backing including arlon, pressure sensitive adhesive, and pre-preg. The use of conformal coating for reliability improvement has also been investigated. Component architectures tested include plastic BGA devices, C2BGA devices, quad flat no-lead (QFN), and discrete resistors. Reliability of the component architectures has been evaluated for hot air solder level and electroless Ni/Au finishes. Crack propagation and intermetallic thickness data has been acquired as a function of cycle count. Reliability data has been acquired on all these architectures. Material constitutive behavior of arlon and pressure sensitive adhesive has been measured using uni-axial test samples. The measured material constitutive behavior has been incorporated into nonlinear finite element simulations. Predictive models have been developed for the dominant failure mechanisms for all the component architectures tested.

Damage mechanics of electronics on metal-backed substrates in harsh environments

The solder joint reliability of ceramic chip resistors assembled to laminate substrates has been a long time concern for systems exposed to harsh environments such as those found in automotive and aerospace applications. This is due to a combination of the extreme temperature excursions experienced by the assemblies along with the large coefficient of thermal expansion mismatches between the alumina bodies of the chip resistors and the glass-epoxy composites of the printed circuit boards (PCBs). These reliability challenges are exacerbated for components with larger physical size (distance to neutral point) such as the 2512 resistors used in situations where higher voltages and/or currents lead to power dissipations up to 1 Watt. In this work, the thermal cycling reliability of several 2512 chip resistor lead free solder joint configurations has been investigated. In an initial study, a comparison has been made between the solder joint reliabilities obtained with components fabricated with both tin-lead and pure tin solder terminations. In the main portion of the reliability testing, two temperature ranges (-40 to 125/spl deg/C and -40 to 150/spl deg/C) and five different solder alloys have been examined. The investigated solders include the normal eutectic SnAgCu (SAC) alloy recommended by earlier studies (95.5Sn-3.8Ag-0.7Cu), and three variations of the lead free ternary SAC alloy that include small quaternary additions of bismuth and indium to enhance fatigue resistance. For each configuration, thermal cycling failure data has been gathered and analysed using two-parameter Weibull models to rank the relative material performances. The obtained lead free results have been compared to data for standard 63Sn-37Pb joints. In addition, a second set of thermally cycled samples was used for microscopy studies to examine crack propagation, changes in the microstructure of the solders, and intermetallic growth at the solder to PCB pad interfaces.

Thermal cycling reliability of lead free solders for automotive applications

The use of chip-scale packages (CSPs) has expanded rapidly, particularly in portable electronic products. Many CSP designs will meet the thermal cycle or thermal shock requirements for these applications. However, mechanical shock (drop) and bending requirements often necessitate the use of underfills to increase the mechanical strength of the CSP-to-board connection. Capillary flow underfills processed after reflow provide the most common solution to improving mechanical reliability. However, capillary underfill dispense, flow, and cure steps and the associated equipment add cost and complexity to the assembly process. Corner bonding provides an alternate approach. Dots of underfill are dispensed at the four corners of the CSP site after solder paste print but before CSP placement. During reflow, the underfill cures, providing mechanical coupling between the CSP and the board at the corners of the CSP. Since only small areas of underfill are used, board dehydration is not required. This paper examines the manufacturing process for corner bonding including dispense volume, CSP placement, and reflow. Drop test results are then presented. A conventional, capillary process was used for comparison of drop test results. Test results with corner bonding were intermediate between complete capillary underfill and nonunderfilled CSPs. Finite-element modeling results for the drop test are also included.

M.N. Islam

Papers

Model for BGA and CSP reliability in automotive underhood applications

Prognostics and Health Management of Electronic Packaging

Damage mechanics of electronics on metal-backed substrates in harsh environments

Thermal cycling reliability of lead free solders for automotive applications

Corner bonding of CSPs: processing and reliability