Shaft Alignment Using Strain Gages: Case Studies

1999 ◽  
Vol 36 (02) ◽  
pp. 77-91
Author(s):  
Bruce Cowper ◽  
Al DaCosta ◽  
Stephen Bobyn
Keyword(s):  
Mathematical Modeling ◽  
Case Studies ◽  
Strain Gage ◽  
The Other ◽  
Strain Gages ◽  
Traditional Methods ◽  
Alignment Condition ◽  
Shaft Alignment ◽  
Marine Vessels ◽  
Optical Laser

Two case studies are presented in which measurement and modeling programs were undertaken to assess the installed shaft alignment condition on marine vessels. One on the CCGS Earl Grey, and the other on the HMCS Huron. In both cases catastrophic damages had previously occurred to shaftline components, which were suspected to be a result of shaft mis-alignment. The damaged components were repaired, and the shaftlines were re-aligned using traditional methods (optical/laser). To assess the alignment condition of the installed shaftlines, measurements were taken by using the strain gage technique. In one case the shaft was realigned according to the strain gage measurements. Mathematical modeling was also conducted to assess the implications of the alignment measurements, and to provide the means to estimate the offsets of the installed bearings from their prescribed positions.

Improvements in Data Acquisition for Propulsion Shaft Alignment

2015 ◽  
Author(s):  
W. David Joiner ◽  
Charles J. Cook
Keyword(s):  
Data Acquisition ◽  
Strain Gage ◽  
Strain Gages ◽  
Construction Process ◽  
Crucial Step ◽  
Ship Construction ◽  
Shaft Line ◽  
Load Cells ◽  
Shaft Alignment

Propulsion shaft alignment is a necessary and crucial step in the ship construction process, with manning and schedule constraints requiring accurate results as efficiently as possible. There are two methods for measuring the bearing loading along the shaft line: strain gages and load cells. The legacy method for using strain gages required a lot of man power and the legacy method for using load cells was dependent on the quality of machinist made available. Strain gages are the transducers of choice for measurement; however the data acquisition, especially for ships with long shafting systems, can require many strain gage positions and personnel to conduct tests. Load cells are used to validate the accuracy of the strain gage method and to calculate the shaft runout at each bearing location.

Shaft Alignment Using Strain Gages

1981 ◽  
Vol 18 (03) ◽  
pp. 276-284
Author(s):  
Albert W. Forrest ◽  
Richard F. Labasky
Keyword(s):  
Strain Gage ◽  
Error Bounds ◽  
Bending Moment ◽  
Bending Moments ◽  
Strain Gages ◽  
Alignment Procedure ◽  
Determinate System ◽  
Shaft Alignment ◽  
Simplified Procedure ◽  
Hydraulic Jacking

A detailed description of the strain-gage shaft alignment procedure is presented, including a comparison between bearing reactions obtained using strain gages and hydraulic jacking. The various gage configurations available for measuring bending moments are discussed and estimates of the resulting error in bending moment are given. A simplified procedure is presented to calculate bearing reactions from the measured moments. Gage site requirements to produce a determinate system are established and a method is outlined to establish bearing reaction error bounds for a combination of gage configurations and sites.

Computer-Aided Alignment of Ship Propulsion Shafts by Strain-Gage Methods

1991 ◽  
Vol 28 (02) ◽  
pp. 84-90
Author(s):  
M. N. Keshava Rao ◽  
M. V. Dharaneepathy ◽  
S. Gomathinayagam ◽  
K. Ramaraju ◽  
P. K. Chakravorty ◽  
...  
Keyword(s):  
Finite Element ◽  
Strain Gage ◽  
Computational Algorithm ◽  
Computer Software ◽  
Strain Gages ◽  
Operational Conditions ◽  
Numerical Example ◽  
Computer Aided ◽  
Shaft Alignment ◽  
Working Out

A generalized procedure to compute all bearing reactions using finite-element and strain-gage techniques is explained. A computational algorithm for computing optimum bearing offsets both for new design as well as existing ships to get optimum bearing reactions is presented along with a numerical example. Advantages of the strain-gage method over other methods in working out a proper shaft alignment are described. A procedure to estimate the existing reactions in all bearings with the aid of strain gages, even for the case of three inaccessible bearings, is explained. By this feature, the strain-gage method is shown to be complete in itself and need not be supplemented by other conventional methods. An ideal architecture for shaft alignment computer software is explained. A technique for online shaft diagnosis in operational conditions using strain gages and onboard computers is shown.

scholarly journals Epistemic artifacts and the modal dimension of modeling

2021 ◽  
Vol 11 (3) ◽  
Author(s):  
Tarja Knuuttila
Keyword(s):  
Mathematical Modeling ◽  
Synthetic Biology ◽  
Case Studies ◽  
Model System ◽  
The Other ◽  
Epistemic Value ◽  
Target System ◽  
Modeling Practice ◽  
Actual Target

AbstractThe epistemic value of models has traditionally been approached from a representational perspective. This paper argues that the artifactual approach evades the problem of accounting for representation and better accommodates the modal dimension of modeling. From an artifactual perspective, models are viewed as erotetic vehicles constrained by their construction and available representational tools. The modal dimension of modeling is approached through two case studies. The first portrays mathematical modeling in economics, while the other discusses the modeling practice of synthetic biology, which exploits and combines models in various modes and media. Neither model intends to represent any actual target system. Rather, they are constructed to study possible mechanisms through the construction of a model system with built-in dependencies.

The Propaganda Feedback Loop

2018 ◽  
Author(s):  
Yochai Benkler ◽  
Robert Faris ◽  
Hal Roberts
Keyword(s):  
Case Studies ◽  
Feedback Loop ◽  
The Other ◽  
Hillary Clinton ◽  
Donald Trump ◽  
The Public ◽  
False Reporting ◽  
Media Ecosystem ◽  
Crowd Out ◽  
Selection Of

This chapter presents a model of the interaction of media outlets, politicians, and the public with an emphasis on the tension between truth-seeking and narratives that confirm partisan identities. This model is used to describe the emergence and mechanics of an insular media ecosystem and how two fundamentally different media ecosystems can coexist. In one, false narratives that reinforce partisan identity not only flourish, but crowd-out true narratives even when these are presented by leading insiders. In the other, false narratives are tested, confronted, and contained by diverse outlets and actors operating in a truth-oriented norms dynamic. Two case studies are analyzed: the first focuses on false reporting on a selection of television networks; the second looks at parallel but politically divergent false rumors—an allegation that Donald Trump raped a 13-yearold and allegations tying Hillary Clinton to pedophilia—and tracks the amplification and resistance these stories faced.

Mounting Works on Paper with Neodymium Magnets

2014 ◽  
Vol 35 (3-4) ◽  
Author(s):  
Martina Noehles ◽  
Lena Niehus
Keyword(s):  
Physical Properties ◽  
Case Studies ◽  
Original Work ◽  
Traditional Methods ◽  
Valuable Addition ◽  
Works Of Art ◽  
Successful Case ◽  
Precautionary Measures ◽  
Neodymium Magnets

AbstractNeodymium magnets have been in use as a mounting technique for works of art on paper for several years; however, the method is still in its infancy. These very strong magnets provide a valuable addition to the traditional methods of mounting artworks on paper and objects made from paper, textile, or other materials for exhibitions. They offer an interesting and elegant alternative to attachment with adhesives, especially when adhesives may not or cannot be applied to the original work. This article addresses the physical properties and manufacture of the magnets, including their coatings and nomenclature. Three successful case studies of mounting artworks on paper with these “super magnets” are presented here. In addition, the limits and possible difficulties of working with neodymium magnets are addressed, as well as precautionary measures to take when handling them.

scholarly journals Ethnic Hatred and Universal Benevolence: Ethnicity and Loyalty in Precolonial Myanmar, and Britain

2021 ◽  
Vol 63 (2) ◽  
pp. 310-338
Author(s):  
Victor Lieberman
Keyword(s):  
Case Studies ◽  
Political Thought ◽  
Western Europe ◽  
Popular Sovereignty ◽  
The Other ◽  
Social Pressures ◽  
Legal Equality ◽  
The One

AbstractInsisting on a radical divide between post-1750 ideologies in Europe and earlier political thought in both Europe and Asia, modernist scholars of nationalism have called attention, quite justifiably, to European nationalisms’ unique focus on popular sovereignty, legal equality, territorial fixity, and the primacy of secular over universal religious loyalties. Yet this essay argues that nationalism also shared basic developmental and expressive features with political thought in pre-1750 Europe as well as in rimland—that is to say outlying—sectors of Asia. Polities in Western Europe and rimland Asia were all protected against Inner Asian occupation, all enjoyed relatively cohesive local geographies, and all experienced economic and social pressures to integration that were not only sustained but surprisingly synchronized throughout the second millennium. In Western Europe and rimland Asia each major state came to identify with a named ethnicity, specific artifacts became badges of inclusion, and central ethnicity expanded and grew more standardized. Using Myanmar and pre-1750 England/Britain as case studies, this essay reconstructs these centuries-long similarities in process and form between “political ethnicity,” on the one hand, and modern nationalism, on the other. Finally, however, this essay explores cultural and material answers to the obvious question: if political ethnicities in Myanmar and pre-1750 England/Britain were indeed comparable, why did the latter realm alone generate recognizable expressions of nationalism? As such, this essay both strengthens and weakens claims for European exceptionalism.

scholarly journals Zero-Tolerance in Catalonia: Policing the Other in Public Space

2020 ◽  
Author(s):  
Martin Lundsteen ◽  
Miquel Fernández González
Keyword(s):  
Public Space ◽  
Case Studies ◽  
Urban Space ◽  
Zero Tolerance ◽  
The Other ◽  
Social Effects ◽  
Main Argument ◽  
Sociocultural Practices

AbstractRecent studies have argued for more nuanced understandings of zero tolerance (ZT) policing, rendering it essential to analyze the significance and actual workings of the policies in practice, including the context in which they are introduced. This article aims to accomplish this through a comparison of two case studies in Catalonia: one in the neighborhood of Raval in Barcelona and one in Salt—a municipality in the comarca (or county) of Girona. We identify a transformation in the use of ZT policies in Catalonia and a contradiction between their social effects and proclaimed objectives. This article attempts to address how specific sociocultural groups gain power and privilege from these policies. The main argument is that a set of commonsensical ideas have become hegemonic, which allows and naturalizes certain sociocultural practices in urban space, while persecuting others, fundamentally pitting two categories against each other: the desired civil citizen and the undesirable and uncivil stranger.

Practical Aspects of Propulsion Shaft Alignment

2021 ◽  
Author(s):  
Kyriakos Avgouleas ◽  
Emmanouil Sarris ◽  
George Gougoulidis
Keyword(s):  
Cost Effectiveness ◽  
Numerical Model ◽  
High Speed ◽  
The Other ◽  
Technical Literature ◽  
Trade Off ◽  
Fea Model ◽  
Shaft Alignment ◽  
Alignment Strategy ◽  
Potential Damage

The economical and operational implications of poor alignment are indisputable for the propulsion shafting system of a commercial vessel. This holds true for naval vessels as well, although far less documented in the technical literature. This paper addresses some of the challenges associated with the proper alignment of a high-speed naval craft, which has been in service for many years. Laser bore-sighting was performed on a Guided Missile Fast Patrol Boat resting on a docking cradle. The measured bearing offsets were input to a FEA model of the shafting system to calculate bearing reactions and detect potential misalignment issues. Subsequent decisions regarding corrective measures take into account the results computed by the numerical model, experience from sister ships, the available documentation from the building yard and several other factors which are discussed in the paper. The solutions proposed are targeted towards a balanced trade-off between cost effectiveness and out-of-service time on one hand, and the risk of potential damage from misalignment on the other hand, which would seriously disrupt the ship’s operational availability. Practical aspects and lessons identified in the process are also presented, which demonstrate the distinct differences in alignment strategy of a high-speed naval craft compared to a typical commercial vessel.

Influencing travel behaviour

2019 ◽  
pp. 107-130
Author(s):  
Stewart Barr ◽  
John Preston
Keyword(s):  
Qualitative Study ◽  
Case Studies ◽  
Behaviour Change ◽  
Social Marketing ◽  
Quantitative Study ◽  
Behavioural Change ◽  
Travel Behaviour ◽  
Air Travel ◽  
The Other ◽  
Car Travel

As travel planning’s theoretical underpinnings have broadened from engineering and economics to embrace psychology and sociology, an emphasis has been placed on social marketing and nudge theory. It is argued that this is consistent with a neo-liberal trend towards governing from a distance. Using two case studies, one a qualitative study of reducing short-haul air travel, the other a quantitative study of attempts to reduce local car travel, it is found that actual behaviour change is limited. This seems to arise because behavioural change has been too narrowly defined and overly identified with personal choice.

Sign in / Sign up

Export Citation Format

Share Document