scholarly journals Linear Vibrations of Statically Indeterminate Rotors on Angular Misaligned Hydrodynamic Bearings

1999 ◽  
Author(s):  
Demetrio C. Zachariadis
Keyword(s):  
Finite Elements ◽  
Linear Stability ◽  
Design Stage ◽  
Angular Misalignment ◽  
Hydrodynamic Bearings ◽  
Early Design ◽  
Rotor Systems ◽  
Early Design Stage ◽  
Stability Threshold ◽  
Linear Vibrations

The influence of journal’s static and dynamic angular misalignment on the synchronous unbalance response and linear stability threshold of statically indeterminate rotors is analysed. Both short and finite bearing models are considered in order to calculate hydrodynamic reactions, and rotating parts are modeled using beam finite elements. The results provide descriptions of the effects of the consideration of the 32 coefficient bearing model on linear vibrations analyses, together with guidelines for early design stage identification of rotor systems sensitive to angular misalignments.

Short Bearing Model for the Evaluation of Journal’s Dynamic Angular Misalignment Effects on Rotor Vibrations

1998 ◽  
Author(s):  
Demetrio C. Zachariadis
Keyword(s):  
Design Stage ◽  
Plain Bearing ◽  
Flexible Rotor ◽  
Angular Misalignment ◽  
Rotor Systems ◽  
Early Design Stage ◽  
Dynamic Coefficients ◽  
Simulation Results ◽  
Analytical Expressions ◽  
Rotor Model

The influence of journal’s dynamic angular misalignment effects on single span flexible rotor vibrations is analysed in a simple system. It comprises a cylindrical plain bearing with two narrow lands separated by an annular groove and a Jeffcott based rotor model. Analytical expressions are presented for all 32 dynamic coefficients of the complete linear bearing model, together with simulation results that provide guidelines for early design stage identification of rotor systems sensitive to angular misalignment.

Identification of Human Errors During Early Design Stage Functional Failure Analysis

2018 ◽  
Author(s):  
Lukman Irshad ◽  
Salman Ahmed ◽  
Onan Demirel ◽  
Irem Y. Tumer
Keyword(s):  
Failure Analysis ◽  
Human Error ◽  
System Level ◽  
Design Stage ◽  
Human Factors Engineering ◽  
Human Errors ◽  
Functional Failure ◽  
Early Design ◽  
Early Design Stage ◽  
Early Design Stages

Detection of potential failures and human error and their propagation over time at an early design stage will help prevent system failures and adverse accidents. Hence, there is a need for a failure analysis technique that will assess potential functional/component failures, human errors, and how they propagate to affect the system overall. Prior work has introduced FFIP (Functional Failure Identification and Propagation), which considers both human error and mechanical failures and their propagation at a system level at early design stages. However, it fails to consider the specific human actions (expected or unexpected) that contributed towards the human error. In this paper, we propose a method to expand FFIP to include human action/error propagation during failure analysis so a designer can address the human errors using human factors engineering principals at early design stages. To explore the capabilities of the proposed method, it is applied to a hold-up tank example and the results are coupled with Digital Human Modeling to demonstrate how designers can use these tools to make better design decisions before any design commitments are made.

scholarly journals A Comprehensive Method of Apportioning Reliability Goals for New Product of Hydraulic Excavator

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Wenting Liu ◽  
Qingliang Zeng ◽  
Lirong Wan ◽  
Chenglong Wang
Keyword(s):  
Real Life ◽  
Chemical System ◽  
Design Stage ◽  
Hydraulic Excavator ◽  
Effect Analysis ◽  
Reliability Allocation ◽  
Early Design ◽  
Construction Machinery ◽  
Early Design Stage ◽  
Fmea Method

It is important to allocate a reliability goal for the hydraulic excavator in the early design stage of the new system. There are some effective methods for setting reliability target and allocating its constituent subsystems in the field of aerospace, electric, vehicles, railways, or chemical system, but until now there is no effective method for the hydraulic excavator or engineering machinery. In this paper, an approach is proposed which combines with the conventional reliability allocation methods for setting reliability goals and allocating the subsystem and parts useful in the early design stage of the hydraulic excavator newly developed. It includes Weibull analysis method, modified Aeronautical Radio Inc. (ARINC) method, and modified systematic failure mode and effect analysis (FMEA) method. After completing reliability allocation, it is necessary to organize the designers and experts to evaluate the rationality of the reliability target through FEMA analysis considering feasibility of the improvement technically for the part which was new developed or had fault in its predecessor. The proposed approach provides an easy methodology for allocate a practical reliability goal for the hydraulic excavator capturing the real life behavior of the product. It proposes a simple and unique way to capture the improvement of the subsystems or components of the hydraulic excavator. The proposed approach could be extended to consider other construction machinery equipment and have practicality value to research excellent mechanical product.

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