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Machinery health prognostics: A systematic review from data acquisition to RUL prediction

Arthur Chickering is Distinguished Professor of Higher Education at Memphis State University. On leave from the Directorship of the Center for the Study of Higher Education at Memphis State, he is Visiting Professor at George Mason University. Zelda Gamson is a sociologist who holds appointments at the John W. McCormack Institute of Public Affairs at the University of Massachusetts-Boston and in the Center for the Study of Higher and Postsecondary Education at the University of Michigan.

Seven Principles for Good Practice in Undergraduate Education: Faculty Inventory. Institutional Inventory.

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Principles Of Heat Transfer In Porous Media

Heat and mass transfer in packed beds

This article presents a methodology for predicting the fluid dynamic behavior of a gear pump over its operating range. Complete pump parameterization was carried out through standard tests, and these parameters were used to create a bond graph model to simulate the behavior of the unit. This model was experimentally validated under working conditions in field tests. To carry this out, the pump was used to drive the auxiliary movements of a drilling machine, and the experimental data were compared with a simulation of the volumetric behavior under the same conditions. This paper aims to describe a method for characterizing any hydrostatic pump as a “black box” model predicting its behavior in any operating condition. The novelty of this method is based on the correspondence between the variation of the parameters and the internal changes of the unit when working in real conditions, that is, outside a test bench.

Parameterization, modeling, and validation in real conditions of an external gear pump

It is very well known that the use of a load-holding valve (LHV) in a hydraulic system introduces additional energy consumption. This article presented a simplified graphical method for analyzing the power requirements of hydraulic systems equipped with load-holding valves for overrunning load control. The method helps to understand the performance of load-holding valves during actuator movement. In addition, it allows visualization of the influence on the overall system consumption of the main parameters (pilot ratio, set pressure) and others such as flow rate, back pressure, and load force. The method is attractive because, with only the pressures at the three ports and the valve relief function curve, it is sufficient to evaluate the energy consumption and to define the power ratio as an index indicating the percentage of energy that is to be used to open the LHV valve. The method was applied to real cases, in particular to two types of lifting mobile machines. It was validated following several outdoor tests on two mobile machines where experimental data were obtained. During tests, both machines were equipped with a set of seven different performance LHV valves. The described method could be beneficial for hydraulic machine manufacturers engaged in designing lifting devices when selecting a suitable valve for energy efficiency applications, especially now that the trend towards electrification is a reality.

/pdf/graphic-method-to-evaluate-power-requirements-of-a-hydraulic-in8op0zs.pdf

Graphic Method to Evaluate Power Requirements of a Hydraulic System Using Load-Holding Valves

The contact problem of a trochoidal gear is a drawback and a well-known performance indicator of a gerotor pump. Although numerical simulations aid in the evaluation of contact stress, the difficult task of determining geometrical parameters, operating conditions, and the number of simulations to run falls to the designer. This paper presents the Taguchi techniques as an effective simulation-based strategy to narrow down the geometrical parameter combinations, reducing the solution space and optimizing the number of simulations. The work is first focused on the validation of the proposed numerical model by means of published contact stress results of recognized researchers in the field, as well as the unification of nomenclature and notation. Then, the Taguchi approach is based on a sequence of four experiments, ranging from the screening case with two levels and seven parameters to multiple levels and four parameters with three software input operating conditions (temperature, torque, and friction coefficient) emulating noise effects. The contact stresses of 128 gear sets, having common volumetric capacity and dimensional constraints to detach mechanical performance from flow rate and casing, were analyzed. Results prove the feasibility of the proposed methodology by identifying the most suitable gear set configuration and predicting the quantifiable performances of a real-working gerotor pump.

https://www.mdpi.com/1996-1073/15/19/7138/pdf?version=1665675726

Taguchi Techniques as an Effective Simulation-Based Strategy in the Design of Numerical Simulations to Assess Contact Stress in Gerotor Pumps

El objetivo principal de las metodologias presentadas en este articulo es determinar las tensiones de contacto en un engranaje de perfiles trocoidales cuando trabaja formando parte de una maquina oleo-hidraulica. Conocer las tensiones de contacto con una maquina ?trocoidal?es importante porque este tipo de maquinas no pueden ser ajustadas para la friccion. La principal dificultad que se plantea en el calculo de las tensiones de contacto consiste en determinar las fuerzas que se transmiten a traves de cada punto de contacto. Debido a la existencia de un numero importante de puntos de contacto para cada instante de tiempo en una rotacion completa del conjunto del engranaje, el problema es hiperestatico. En la primera y segunda seccion de este articulo se presenta un modelo analitico para el calculo de la tensiones de contacto en una maquina ?trocoidal? tipo gerotor, desestimando la friccion en los puntos de contacto. A partir de este punto el comportamiento del conjunto del engranaje es evaluado a traves del calculo de la maxima tension de contacto normal en los dientes del engranaje. En la tercera seccion del articulo se presenta un estudio de la misma maquina mediante elementos finitos y sus resultados. En la cuarta parte del articulo se describe el trabajo experimental usando un modelo prototipo del conjunto del engranaje de la misma maquina que proporciona el rango de magnitud de la maxima tension de contacto en un par de dientes a traves de la tecnica de la foto-elasticidad. Finalmente los resultados de los dos modelos y de los ensayos experimentales son comparados aportando conclusiones muy interesantes.

El problema del contacto en bombas de engranajes de perfil trocoidal

Mobile machinery manufacturers must face and deal with reducing fuel consumption, rising prices, and environmental pollution. The development of methods to evaluate the efficiency and effectiveness of the energy performance of hydraulically actuated systems has become a priority for researchers and OEMs, Original Equipment Manufacturers. In this paper, a new methodology that is based on Key Performance Indicators, KPI, is proposed with different goals: (i) to evaluate the energy performance and the monitoring of its evolution in the different stages of its life cycle (design, commissioning, optimization, retrofit, etc.); (ii) compare the energy levels between machines of different sizes and different brands in a benchmarking process; and (iii) establish a database that is state of the art, which facilitates setting achievable goals or limits for improvement. These KPI values can be deduced simply from the energy balances that were made from the experimental study of various machines over a relatively long period. This methodology has been applied to typical hydraulic systems for lifting and lowering loads that are used in a wide variety of mobile machines of different mechanical designs and sizes. Still, it can be included in the generic name of “loaders”. A KPI’s values for the three machines are presented in a dashboard as a decision-making tool.

/pdf/energy-key-performance-indicators-for-mobile-machinery-1vklktz1.pdf

P. J. Gamez-Montero

Papers

Parameterization, modeling, and validation in real conditions of an external gear pump

Graphic Method to Evaluate Power Requirements of a Hydraulic System Using Load-Holding Valves

Taguchi Techniques as an Effective Simulation-Based Strategy in the Design of Numerical Simulations to Assess Contact Stress in Gerotor Pumps

El problema del contacto en bombas de engranajes de perfil trocoidal

Energy Key Performance Indicators for Mobile Machinery