A Novel framework for relationship of manufacturing tolerance and component-level performance of journal bearings

2022 ◽  
Author(s):  
D. Hidalgo ◽  
R.O. Ruiz ◽  
A. Delgado
Keyword(s):  
Journal Bearings ◽  
Component Level ◽  
Manufacturing Tolerance ◽  
Relationship Of ◽  
Level Performance

scholarly journals QiOi: Performance Isolation for Hyperledger Fabric

2021 ◽  
Vol 11 (9) ◽  
pp. 3870
Author(s):  
Jeongsu Kim ◽  
Kyungwoon Lee ◽  
Gyeongsik Yang ◽  
Kwanhoon Lee ◽  
Jaemin Im ◽  
...  
Keyword(s):  
Data Centers ◽  
Component Level ◽  
Isolation Technique ◽  
Cloud Data ◽  
Cpu Scheduling ◽  
Performance Isolation ◽  
Cloud Data Centers ◽  
A New Technique ◽  
The Impact ◽  
Level Performance

This paper investigates the performance interference of blockchain services that run on cloud data centers. As the data centers offer shared computing resources to multiple services, the blockchain services can experience performance interference due to the co-located services. We explore the impact of the interference on Fabric performance and develop a new technique to offer performance isolation for Hyperledger Fabric, the most popular blockchain platform. First, we analyze the characteristics of the different components in Hyperledger Fabric and show that Fabric components have different impacts on the performance of Fabric. Then, we present QiOi, component-level performance isolation technique for Hyperledger Fabric. The key idea of QiOi is to dynamically control the CPU scheduling of Fabric components to cope with the performance interference. We implement QiOi as a user-level daemon and evaluate how QiOi mitigates the performance interference of Fabric. The evaluation results demonstrate that QiOi mitigates performance degradation of Fabric by 22% and improves Fabric latency by 2.5 times without sacrificing the performance of co-located services. In addition, we show that QiOi can support different ordering services and chaincodes with negligible overhead to Fabric performance.

scholarly journals Misalignment in Gas Foil Journal Bearings: An Experimental Study

2008 ◽  
Author(s):  
Samuel A. Howard
Keyword(s):  
Journal Bearings ◽  
System Level ◽  
Design Parameters ◽  
Foil Bearing ◽  
Alignment System ◽  
Successful Design ◽  
Shaft Alignment ◽  
Bearing Force ◽  
Management Schemes ◽  
Level Performance

As gas foil journal bearings become more prevalent in production machines, such as small gas turbine propulsion systems and microturbines, system level performance issues must be identified and quantified in order to provide for successful design practices. Several examples of system level design parameters that are not fully understood in foil bearing systems are thermal management schemes, alignment requirements, balance requirements, thrust load balancing, and others. In order to address some of these deficiencies and begin to develop guidelines, this paper presents a preliminary experimental investigation of the misalignment tolerance of gas foil journal bearing systems. Using a notional gas foil bearing supported rotor and a laser-based shaft alignment system, increasing levels of misalignment are imparted to the bearing supports while monitoring temperature at the bearing edges. The amount of misalignment that induces bearing failure is identified and compared to other conventional bearing types such as cylindrical roller bearings and angular contact ball bearings. Additionally, the dynamic response of the rotor indicates that the gas foil bearing force coefficients may be affected by misalignment.

scholarly journals Misalignment in Gas Foil Journal Bearings: An Experimental Study

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Samuel A. Howard
Keyword(s):  
Journal Bearings ◽  
System Level ◽  
Design Parameters ◽  
Foil Bearing ◽  
Alignment System ◽  
Successful Design ◽  
Shaft Alignment ◽  
Bearing Force ◽  
Management Schemes ◽  
Level Performance

As gas foil journal bearings become more prevalent in production machines, such as small gas turbine propulsion systems and microturbines, system level performance issues must be identified and quantified in order to provide for successful design practices. Several examples of system level design parameters that are not fully understood in foil bearing systems are thermal management schemes, alignment requirements, balance requirements, thrust load balancing, and others. In order to address some of these deficiencies and begin to develop guidelines, this paper presents a preliminary experimental investigation of the misalignment tolerance of gas foil journal bearing systems. Using a notional gas foil bearing supported rotor and a laser-based shaft alignment system, increasing levels of misalignment are imparted to the bearing supports while monitoring temperature at the bearing edges. The amount of misalignment that induces bearing failure is identified and compared with other conventional bearing types such as cylindrical roller bearings and angular contact ball bearings. Additionally, the dynamic response of the rotor indicates that the gas foil bearing force coefficients may be affected by misalignment.

Identifying Critical Connections for the Global Performance of Steel Moment Resisting Frames

2018 ◽  
Vol 763 ◽  
pp. 165-173
Author(s):  
Paul Steneker ◽  
Lydell D.A. Wiebe ◽  
Andre Filiatrault
Keyword(s):  
Local Deformation ◽  
System Level ◽  
Single Type ◽  
Northridge Earthquake ◽  
Component Level ◽  
Moment Resisting Frames ◽  
Global Performance ◽  
Moment Resisting ◽  
Rbs Connections ◽  
Level Performance

The investigations following the unacceptable performance of moment resisting frames (MRFs) in the 1994 Northridge Earthquake led to the development of a variety of alternative ductile connections. Tests have shown that these connections have reliable component-level performance, leading to them being recommended in standards worldwide as pre-qualified for MRFs. Current design practice consists of applying a single type of ductile connection, often the reduced beam section (RBS), uniformly throughout an entire frame. These connections are detailed and inspected to ensure that each connection has a similar minimum deformation capacity throughout the building, regardless of local deformation demands.This paper examines the potential design implications of identifying local areas within a MRF having the greatest joint rotational demands. Once identified, the connections at these locations are deemed critical to the global performance of the frame. First, the collapse analysis of a six-storey MRF with well-detailed RBS connections was conducted to quantify an upper bound system-level performance. Thereafter, a lower bound system-level performance was determined by considering a frame constructed using only connections with a lowered rotational capacity. Subsequent series of analyses were conducted to identify critical locations within the frame where RBS connections must have a high reliable rotational capacity to ensure adequate system-level performance.

scholarly journals A simulation-based approach to modeling component interactions during design of flapping wing aerial vehicles

2019 ◽  
Vol 11 ◽  
pp. 175682931882232
Author(s):  
John Gerdes ◽  
Hugh A Bruck ◽  
Satyandra K Gupta
Keyword(s):  
Predictive Accuracy ◽  
Voltage Drop ◽  
Flapping Wing ◽  
System Level ◽  
Deformation Model ◽  
Loading Conditions ◽  
Component Level ◽  
Battery Model ◽  
Aerial Vehicle ◽  
Level Performance

A new flapping wing aerial vehicle (FWAV) simulation methodology is presented that combines models of the key subsystems: (1) the actuator, (2) the battery, and (3) the wings. This approach captures component interactions that are inherently coupled in order to realize system-level designs for optimal system performance. The approach demonstrates that coupling between wing sizing, flapping motions, and loading conditions propagate into the motor–battery model to alter system-level performance properties. For the actuator subsystem model, a generalized servo motor using empirically derived coefficients to describe torque and angular velocity bandwidth in terms of voltage and current. This model is coupled with a lithium polymer battery model accounting for the nonlinear voltage drop and capacity derating effects associated with loading conditions. For aerodynamic predictions of the wing subsystem, a blade element model for predicting aerodynamic forces is coupled with an elastic wing deformation model that accounts for bending and twisting of the blade elements. System-level performance is then modeled in a design case study by coupling all of the subsystem models to account for relevant interactions, which generates a design trade space spanning a range of wing sizes, airspeeds, and flapping condition. The results from the simulation offer insight into vehicle configuration settings that provide maximum performance in terms of lift and endurance for the Robo Raven II flapping wing aerial vehicle. Experimental validation of the modeling approach shows good predictive accuracy. In addition, the presented framework offers a generalized approach for coupling interacting subsystems to improve overall predictive accuracy and identify areas where component-level improvements may offer system-level performance gains.

A SIMPLE APPROACH FOR THE TOLERANCE DESIGN OF WATT-I TYPE SIX-BAR HINGE MECHANISM USING TAGUCHI METHOD

2006 ◽  
Vol 13 (02) ◽  
pp. 157-169 ◽  
Author(s):  
FU-CHEN CHEN ◽  
YIH-FONG TZENG
Keyword(s):  
Taguchi Method ◽  
Signal To Noise Ratio ◽  
Control Factor ◽  
Tolerance Design ◽  
Manufacturing Tolerance ◽  
Response Table ◽  
Product Variation ◽  
Key Dimensions ◽  
Relationship Of

This paper uses the Taguchi method on the tolerance design of a hinge mechanism with the aim of obtaining a design that is insensitive to variations in manufacturing tolerance and joint clearance. The contribution of each control factor in the mechanism to the variations was also quantified. From the analysis of the response table and diagram, it was concluded that the dimension r1, r2, r4 and β had a significant effect on the quality of the mechanism, contributing a total of 82.36% to product variation and were consequently named the key dimensions. The tolerance of these factors must therefore be tightened to improve the quality of the mechanism. Through a series of confirmation experiments, it was revealed that tightening the tolerance resulted in an increase in the S/N (signal to noise) ratio by 1.851 db and a reduction in product variation by 19.25% from the original 80.75%. The proposed method does not require complex mathematical derivatives, but simply the input and output relationship of the system. The method proposed in this study can be applied to all types of mechanism.

A General Purpose Test Facility for Evaluating Gas Lubricated Journal Bearings

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
B. Ertas ◽  
M. Drexel ◽  
J. Van Dam ◽  
D. Hallman
Keyword(s):  
Load Capacity ◽  
Aircraft Engine ◽  
General Purpose ◽  
Journal Bearings ◽  
Test Facility ◽  
Test Rig ◽  
Component Level ◽  
Simultaneous Application ◽  
Design Elements ◽  
Lift Off

The present work describes the detailed design and operational capabilities of a general purpose test facility developed to evaluate the dynamics and performance of gas lubricated journal bearings. The component level test facility was developed to serve as an initial tollgate test platform for certifying gas lubricated journal bearings into aircraft engine applications. A rotating test rig was engineered to test 70–120 mm diameter bearings at 40,000–80,000 rpm and 1200°F. The test rig described in this paper possesses design elements that enable the simultaneous application of dynamic and static load profiles of up to 1000 lb while monitoring and measuring the bearing torque. This capability allows for the characterization of several critical metrics such as bearing lift off speed characteristics, load capacity, and frequency dependent rotordynamic force coefficients. This paper discusses the functionality of the test facility and presents sample test measurements from several experiments.

Effect of Uncertainties in the Estimation of Dynamic Coefficients on Tilting Pad Journal Bearings

2016 ◽  
Author(s):  
Rafael O. Ruiz ◽  
Sergio E. Diaz
Keyword(s):  
Surrogate Model ◽  
Journal Bearing ◽  
Deterministic Model ◽  
Journal Bearings ◽  
Kriging Interpolation ◽  
Manufacturing Tolerance ◽  
Dynamic Coefficients ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearing ◽  
Tilting Pad Journal Bearings

It has been identified that small variations in the pad clearance and preload of a Tilting Pad Journal Bearing lead to important variations in their dynamic coefficients. Although this variation trend is already identified, a more robust statistical analysis is required in order to identify more general tendencies and quantify it. This work presents a framework that helps to identify the relation between the manufacturing tolerance of the bearing (reflected in the pad clearance and preload) and the expected variations on the dynamic coefficients. The procedure underlies the adoption of a surrogate model (based on Kriging interpolation) trained by any deterministic model available to predict dynamic coefficients. The pad clearance and preload are considered uncertain parameters defined by a proper probability density function. All statistical quantities are obtained using stochastic simulation, specifically adopting a Monte Carlo simulation employing the surrogate model. The framework is illustrated through the study of a five pad bearing.

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