scholarly journals Simulating Corrective Maintenance: Aggregating Component Level Maintenance Time Uncertainty at the System Level

2013 ◽  
Vol 16 ◽  
pp. 459-468
Author(s):  
Elizabeth A. Saltmarsh ◽  
Dimitri N. Mavris
Keyword(s):  
System Level ◽  
Component Level ◽  
Corrective Maintenance ◽  
Time Uncertainty ◽  
Maintenance Time

Dynamic Infrared System Level Fault Isolation

2003 ◽  
Author(s):  
John A. Naoum ◽  
Johan Rahardjo ◽  
Yitages Taffese ◽  
Marie Chagny ◽  
Jeff Birdsley ◽  
...  
Keyword(s):  
Fault Isolation ◽  
System Level ◽  
System Component ◽  
Component Level ◽  
Ir Imaging ◽  
Non Destructive

Abstract The use of Dynamic Infrared (IR) Imaging is presented as a novel, valuable and non-destructive approach for the analysis and isolation of failures at a system/component level.

System Level Bench Test for Trailing Arm Strength Estimation

2006 ◽  
Author(s):  
Jaychandar Muthu ◽  
Kanak Soundrapandian ◽  
Jyoti Mukherjee
Keyword(s):  
Failure Mode ◽  
Real Life ◽  
Element Model ◽  
Suspension System ◽  
System Level ◽  
Bench Test ◽  
Component Level ◽  
Arm Strength ◽  
Bench Testing ◽  
Nonlinear Finite Element Model

For suspension components, bench testing for strength is mostly accomplished at component level. However, replicating loading and boundary conditions at the component level in order to simulate the suspension system environment may be difficult. Because of this, the component's bench test failure mode may not be similar to its real life failure mode in vehicle environment. A suspension system level bench test eliminates most of the discrepancies between simulated component level and real life vehicle level environments resulting in higher quality bench tests yielding realistic test results. Here, a suspension level bench test to estimate the strength of its trailing arm link is presented. A suspension system level nonlinear finite element model was built and analyzed using ABAQUS software. The strength loading was applied at the wheel end. The analysis results along with the hardware test correlations are presented. The reasons why a system level test is superior to a component level one are also highlighted.

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 Review of Recent Advancements in Offshore Wind Turbine Technology

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 579
Author(s):  
Taimoor Asim ◽  
Sheikh Zahidul Islam ◽  
Arman Hemmati ◽  
Muhammad Saif Ullah Khalid
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Structural Integrity ◽  
Turbine Blades ◽  
Offshore Wind ◽  
System Level ◽  
Offshore Wind Turbine ◽  
Component Level ◽  
Foundation Design ◽  
Offshore Wind Turbines

Offshore wind turbines are becoming increasingly popular due to their higher wind energy harnessing capabilities and lower visual pollution. Researchers around the globe have been reporting significant scientific advancements in offshore wind turbines technology, addressing key issues, such as aerodynamic characteristics of turbine blades, dynamic response of the turbine, structural integrity of the turbine foundation, design of the mooring cables, ground scouring and cost modelling for commercial viability. These investigations range from component-level design and analysis to system-level response and optimization using a multitude of analytical, empirical and numerical techniques. With such wide-ranging studies available in the public domain, there is a need to carry out an extensive yet critical literature review on the recent advancements in offshore wind turbine technology. Offshore wind turbine blades’ aerodynamics and the structural integrity of offshore wind turbines are of particular importance, which can lead towards system’s optimal design and operation, leading to reduced maintenance costs. Thus, in this study, our focus is to highlight key knowledge gaps in the scientific investigations on offshore wind turbines’ aerodynamic and structural response. It is envisaged that this study will pave the way for future concentrated efforts in better understanding the complex behavior of these machines.

scholarly journals On relative ageing of coherent systems with dependent identically distributed components

2020 ◽  
Vol 52 (1) ◽  
pp. 348-376
Author(s):  
Nil Kamal Hazra ◽  
Neeraj Misra
Keyword(s):  
Sufficient Conditions ◽  
System Level ◽  
Hazard Rates ◽  
Coherent System ◽  
Coherent Systems ◽  
Component Level ◽  
Distributed Components ◽  
Two Systems

AbstractRelative ageing describes how one system ages with respect to another. The ageing faster orders are used to compare the relative ageing of two systems. Here, we study ageing faster orders in the hazard and reversed hazard rates. We provide some sufficient conditions for one coherent system to dominate another with respect to ageing faster orders. Further, we investigate whether the active redundancy at the component level is more effective than that at the system level with respect to ageing faster orders, for a coherent system. Furthermore, a used coherent system and a coherent system made out of used components are compared with respect to ageing faster orders.

Stochastic Comparisons Between Coherent Systems with Active Redundancies Under Proportional Hazards and Reversed Hazards Models

2020 ◽  
Vol 28 (01) ◽  
pp. 2150007
Author(s):  
Maryam Kelkinnama
Keyword(s):  
Proportional Hazards ◽  
Sufficient Conditions ◽  
System Level ◽  
Coherent Systems ◽  
Stochastic Comparisons ◽  
Component Level ◽  
Lifetime Distributions ◽  
Hazards Model ◽  
System Improvement

This paper is concerned with the problem of stochastic comparisons between the lifetimes of two coherent systems with active redundancy. For this purpose, we consider both the active redundancy at the system level and the redundancy at the component level. We assume that the original components are identically distributed and possibly dependent. It is also assumed that for each component, there are [Formula: see text] redundant components with possibly different lifetime distributions which follow the proportional hazards (reversed hazards) model. Under some conditions on the domination function of the system, we compare the lifetimes of the systems based on majorization orders between the parameter vectors of the proportionality of the component lifetimes. We also give sufficient conditions under which adding more redundant components imply the system improvement.

Comparative Study of Cyclic and Shake Table Tests for Simple for Dead Load and Continuous for Live Load Steel Bridge System in Seismic Area

2020 ◽  
Vol 2674 (7) ◽  
pp. 233-243
Author(s):  
Amir Sadeghnejad ◽  
Sheharyar Rehmat ◽  
Islam M. Mantawy ◽  
Atorod Azizinamini
Keyword(s):  
Plastic Hinge ◽  
Longitudinal Direction ◽  
System Level ◽  
Live Load ◽  
Shake Table ◽  
Steel Bridge ◽  
Dead Load ◽  
Design Standards ◽  
Component Level ◽  
Bridge System

A new superstructure to pier connection for simple for dead load and continuous for live load (SDCL) steel bridge system in seismic areas was developed. As proof of concept, component level and system level tests were carried out on scale models. The component test was conducted under cyclic loading and the results showed satisfactory performance conforming to design standards. The same detail was incorporated in a system level shake table testing which was subjected to bidirectional earthquake excitations. The results showed that the connection behaved well under high levels of drift and acceleration. The capacity protected elements sustained minimal damage and the plastic hinge was limited to a predefined location in the column. In this paper, a summary of results from both tests is presented and compared. The results showed that the SDCL components remained within the elastic range. It was concluded that the dowel bars in the cap beam are the main load-carrying elements under excitations in the longitudinal direction of the bridge and the provisions of current design codes are adequate for the design of these reinforcing bars. Both test protocols showed similar behavior despite the differences in construction methods and material properties.

Farmers' role in sustainable agriculture research

1990 ◽  
Vol 5 (4) ◽  
pp. 178-182 ◽  
Author(s):  
William Lockeretz ◽  
Molly D. Anderson
Keyword(s):  
Sustainable Agriculture ◽  
Agricultural Research ◽  
Dominant Role ◽  
Full Range ◽  
System Level ◽  
Component Level ◽  
Versus System ◽  
Level Versus ◽  
Publicly Supported

AbstractInvolvement of farmers in sustainable agricultural research can have important benefits, since farmers originated many sustainable agriculture innovations and can contribute a valuable perspective different from that of researchers. However, this does not mean, as is sometimes said, that all kinds of sustainable agricultural research necessarily should give farmers a major role—perhaps the dominant role—in choosing topics and overseeing the work. This belief overlooks the fact that farmers are just one of many groups that publicly supported research is supposed to serve and that their interests do not by themselves embody the full range of goals that sustainable agriculture tries to achieve. Moreover, although farmers can bring valuable insights to research, these alone will not be enough to insure that a sustainable agriculture research program has an appropriate mix of applied versus basic, short-term versus long-term, and component-level versus system-level studies.

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