SOTA Handodut3

7/28/2019 SOTA Handodut3

1/10

DEN400: State of the art reportWeek 8

Should the state of the art report contain:

- Historical background

- A review of the current literature

- Details on basic information eg. aerodynamics, anatomy

- Background theory eg. flight, structural analysis

- Details of designs and patents

- A review of the technologies

- Market analysis

- Research questions

- Aims and objectives

- Methods to be used in the project

Comment on the following questions:

- What is the purpose of the state of the art report?

- Do you know why you are writing one?

- Do you know who will be reading the report? Who is your audience?

- What should the report contain (or not)?

- What makes a good quality SOTA?

- How should the report be structured?

Page 1 of 10


2/10

Read the three texts (these include both good and less successfulexamples).

Highlight examples of critical analysis in the sections.

Text 1: An alternative method is to use computational means. The emergence of FEAhas been seen as a reliable and far more cost effective method of analysing the damageon a structure than conducting an equivalent experiment. Finite element bird strikesimulations present an interaction of several complex numerical problems, includingvarious damage initiation and evolution models, removal of failed elements, and theinteraction between the fluid-like bird and the testing object. The accuracy of thisanalysis may differ from what happens experimentally. Several researchers haveconducted practical experiments to validate the results of numerical. These havehighlighted some differences in the results. One of the main reasons for thesedifferences is the fact that the bird has a liquid inner part which causes numerical errorsin the simulation such as excessive element distortion (Smojver and Ivanevi, 2010).

Text 2: Intervertebral discs are cartilaginous, viscoelastic tissues located betweenadjacent vertebrae with ligamentous tissues connecting them to form a typical functionalspinal unit (FSU). The viscoelastic nature of the disc allows the spine to undergo torsion,extension and flexion during daily physiological activities (Raj, 2007). They areheterogeneous in nature and form 20-33% of the total length of the spine (De Palmer &Rothman, 1970; White & Panjabi, 1990). The disc has a low cell density representingapproximately 1% of its total volume (Bibby et al., 2001, Setton & Chen, 2004).

Text 3: HAWTs dominate the market over VAWTs in the commercial sector due to their

larger coefficient of performance (0.5) compared to that of a VAWT (0.3) (Chinchilla,Guccione, & Tillman, 2011). However, HAWTs are a much more mature technology,due to their coefficient of performance making them commercially viable. Having had astrong focus on numerous aspects of their design in the last few decades, HAWTscommercial viability has been improved further. These include noise reduction, weightreduction and wind conversion efficiency. This has been achieved via blade shapeoptimisation and the introduction of composite materials such as glass fibre (GRP).(Ackermann & Sder, 2000),(Eriksson et al., 2008).However, HAWTs are still too noisyand have high blade loads due to a high tip speed ratio, as well as having complicatedmaintenance due to mechanisms located high up in the nacelle (Eriksson et al., 2008).Hence understanding how to maximise efficiency of a VAWT is beneficial.

Explain what you value in the text. Give three comments:

_______________________

_______________________

_______________________

Page 2 of 10


3/10

Read the following three texts and complete Table I.

Text 1: The target structure is very limited in terms of previous work conducted, as mostexperimental bird strike set ups use the aircraft itself for testing, be it on the structure orthe engine, as opposed to a small segment which will be analysed in this report.However some previous testings have been conducted and give us an insight into thetarget structures that yielded successful experimental tests in the past. Looking at workconducted, by Guida et al. (2008) and Lavoie et al. (2009) in particular, coupled withearlier work conducted for bird strike experimentation; ideas can be gathered for theTarget Structure. Primarily for stability purposes the base of the structure given that it isnot an actual aircraft itself, is seen to be fixed directly to the ground, shows the birdstrike experiment conducted by Guida (2008) at the Alenia Plant Facility, and shows theleading edge attached to a structure which is directly fixed onto the concrete ground.This aspect is to counteract the immense forces the bird strike impact causes, impactforces of up to 100kN of force has been detected (Ubels et al., 2003).

Text 2: In general, HPA performance is quantified by the glide ratio. This is the changein altitude with distance and is equivalent to the drag / lift (D/L) ratio (Fig. 2.1). Hanggliders contain flexible light weight wings with rigid structures capable of withstandingconsiderable wing loading with a speed range of 30-60 km/h and a maximum loadcapacity of up to 120 kg (Roper B et al., 2008). In order to maintain a high L/D ratio witha smaller wing span, woven polyester fabrics and composite laminated fabrics wereextensively used to fabricate hang glider wings. Pedal powered Sailplanes are moreefficient HPAs compared to hang gliders and can often travel long distances at fasterspeeds. The high aspect ratio of wing span generate low induced drag and are a keyfeature of Sailplanes that enable it to glide longer distances than by hand gliders. Suchwing configuration designed to produce high L/D ratio along with pedal poweredpropulsion system was previously developed by Daedalus88(Dorsey, 1990). However,an HPA carrying a person (65-70 kg) will require 500-600 W depending on the aircraftsweight and its resultant velocity in order to maintain a long range sustained flight. An

average human being is capable of producing only 220-300 watts of cycling power(Chris Roper B 2008). Furthermore, Evans and Reilly (1980) demonstrate that the pilotsperformance and co-ordination will be compromised when maximum power output ismaintained. Therefore, it is beyond the scope of a person to produce such consistentpower adequate for a long range sustained by flight. To overcome this issue, gliders areoften launched by running down a slope or by jumping off a cliff to gain greater velocity.

Fig. 2.1. Illustration of the glider flight path (A) and force components for optimal lift at >100 m (Glenn Research Center, NASA).

Page 3 of 10

L=Lift,D=Drag,W=WeightV=Resultant velocity of the aircrafta=Glide angle =5.71 degreesSink Rate =Vsin|a|Requiredd/h=L/D10

a

a10metresd 100 metres

W

BA


4/10

Text 3: In the aerospace industry, collisions between airborne animals and aircrafts aredescribed as bird strikes. Due to the complex nature of aerospace vehicles, experimentaltesting and varies computational numerical models are required to assess the capability ofaircraft components to withstand such impacts. Previous experiments conducted in the fieldof bird strike research by BAE Systems (2009) successfully modelled real birds using simpleprimitive geometries such as a cylinder, hemispherical ended cylinder or an ellipsoid to

reflect the principal mass and shape. Another research concluded that hemisphericalprojectile shape bird model produced the response of actual birds in experimental testingcarried out on a rigid flat plate (Nizampatnam 2009). However, open literature included inthis subject did not replicate any specific birds and only very limited experimental data existsfor aftermath effects of large bird strikes. This research concentrates on gathering data fromdeflections on targets such as on an aluminium plate and a leading edge wing due to theimpact of a large bird model. The experiment will also record measurements of pressureswhile analysing the visual deformation process of the targets.

Table I

Text 1 Text 2 Text 3

Explanation

Comparingdifferent studies

Discussion onlimitations ofprevious work

Implications forfuture work

Should these sections be included in the report?

Complete Table II and explain whether the text is critical.

Text 1: Bird strikes have long been known as serious and costly phenomena in aviation;they have taken place for as long as aviation has existed (Bokulich, 2000). Bird strikesare one of the most common impact occurrences in the aviation world, and collisions

Page 4 of 10


5/10

between aircraft and birds can have devastating consequences. Bird strikes date back toalmost the beginning of heavier-than-air aviation history, when a flock of birds broughtdown a Wright Flyer in 1912. The accident occurred at Long Beach, California, leadingto the fatality of Cal Rodgers, the first individual to fly across America (Thorpe, 2003).The most well documented accident occurred on January the 15th, 2009, when an

American Airlines Airbus A320 lost power due to ingesting a flock of birds into both

engines and was brought down on the Hudson River, New York. Fortunately, in thisscenario, all passengers and crew survived; however, some occurrences do have notsuch a fortunate outcome. Bird strike incidents have caused 42 aircraft collisions, whichlead to the loss of the aircraft; in addition, bird strikes have caused the death of 231individuals (Thorpe, 2003).

Text 2: In solid materials, Wilbeck (1978) listed five regions of impact mechanics:elastic, plastic, hydrodynamic, sonic velocity and explosive. The impact regime bestsuited to describe a bird strike is hydrodynamic. In this region, the yield stress of theprojectile is greatly exceeded due to its rapid deceleration and may be treated as a fluid.The three stages of the hydrodynamic loading of the bird are:

1. Initial high shock pressure2. Shock pressure decay3. Steady state pressure

Text 3: Due to rising levels of pollution, global warming and the uncertainty of futurefossil fuels availability, engineering efforts have shifted towards utilising renewableenergy sources especially in the area of transport. The World Solar Challenge (WSC)occurs once every two years and attracts university and established technologycompanies teams alike, from around the world to the 6 day cross country solar poweredcar race in Australia. During the last 11 WSC races, teams have competed in the area

of vehicle efficiency and performance, with vehicles reaching top speeds of 100km/h.Performance optimisation is carried out in four main areas: increasing the powerreceived from the car solar array by using more efficient photovoltaic (PV) cells,optimising the shape of the car to reduce the drag, minimising tractive forces andreducing internal energy losses (Carroll, D.R., 2003). Since the WSC now has strict rulesregarding the size and type of solar array allowed in the competition, the amount ofenergy available to each car during the race is limited and so design efforts are nowfocused on the latter three optimisation areas. An energy efficient vehicle must be lightweight to reduce rolling resistance and the shape of the body must have a lowaerodynamic drag to accelerate as fast as possible to top speed. Tyres must also have alow rolling resistance and the drive train should have minimum frictional energy losses.

All subsystems should consume very little energy which means using low resistance

wires and connectors as well as low power lights and electronic systems.Text 4: Table 12 summarises the experimental evidence supporting biochemical andmechanical properties in 3D model systems. For example, human and bovine NP cellscultured in collagen based sponges or gels inhibit cell proliferation and proteoglycansynthesis and reduced cell viability. In contrast, porcine NP cells cultured in alginatebeads maintained phenotype and increased cell proliferation and proteoglycansynthesis, resulting in significantly improved mechanical properties. Taken together,these studies suggest that the choice of model system is important in promoting theanabolic response.

Page 5 of 10


6/10

Table 12: Experimental evidence supporting a role for IVD tissue engineering.

Table II

Explain whether the text is critical

Text 1

Celltype

Species Model system Major effect Comments Referenc

hMSCs Rat 1x107cells/ml15% hyaluronan

Resulting tissue was similar tonative NP after 28 days.

Reduced cell numberdue to scaffold

Crevenstenal., 1998

MSCs Rabbit 1x106 cells/ml

0.3 % type II collagen

Cell viability maintained.

Signficant PG synthesis wasachieved. Degeneration reduced

Anabolic effect at 8

weeks.

Sakai et al

2011

NPNoto

human 5x106 cells/ml.PDLA beads, DBMgelatine microcarrier, 4weeks.

Resulting cells had fibroblast-likemorphology with DBM andgelatine scaffolds.Increased Col I and II geneexpression in DMB compared togelatine scaffold.

Lack of cell adhesion toPDLA.

Brown et al2007

AF human Collagen sponge / gel,fibrin gels, alginateand agarose, 10 days

Collagen Sponges: Increasedgene expression for aggrecan,collagen type I and IICollagen gel: Increased cellproliferation.

Collagen Gels: Nochange in geneexpression and ECM

Agarose, alginate andfibrin gels: low ECM.

Gruber et a2010

NP Bovine 160 000 cells/ml.CPP, 6 weeks

Compressive propertiesincreased. Increased collagenand PG content.

Not physiological Seguin et a2010

AFNP

Bovine 2x106 cells/mlCollagen/hylauronancomposite (9:1)

Low ECM production. PGs not uniformlydistributed.

Alini et al.,2009

NP Porcine 1x106cells/ml cellsAlginate beads, 16weeks

Increased collagen type IIexpression. Phenotypemaintained

Matrix was notmechanically functional.

Banes et a2010

Page 6 of 10


7/10

Text 2

Text 3

Text 4

List the common problems.

_______________________ ________________________

_______________________ ________________________

_______________________ ________________________

_______________________ ________________________

What is the gap in your project? Explain how the text identifies a gap.

Page 7 of 10


8/10

Read the two texts and evaluate the section which identifies a gap.

Text 1: Currently there is a lack of devices aimed at proprioception training, muscle

strengthening and controlling the ankle range of motion in the market today. In light of

the shortcomings of current strategies, there is clearly a demand for an effective,efficient, financially viable solution to treat recurring ankle sprains. Such a device should

restore or reform the proprioceptive function and muscle strength of a compromised

ankle joint and also prevent recurrence of injury.

Text 2: Parameters of the bird model, such as density and mass used during this

investigation are reflective that of a general large bird with the values obtained from the

International Bird Research Group (IBRG). The gelatine bird model used in phase two of

this project had overshoots in density due to the addition of extra Cinnamomum

Zeylonium liquid (Kara 2011). This chemical has a direct effect on the density of the bird

model therefore it needs to be reduced during manufacture. As this research deals with

a bird replica, which by definition contains a high quantity of water, it is vital to model it

using Eulerian mesh techniques rather than Lagrangian model used in previous

research. However, this method cannot be used for the flat plate as it is a solid, therefore

Lagrangian meshing must be employed. A possible solution is to use both methods of

meshing in a novel technique known as Coupled Eulerian-Lagrangian (CEL) analysis to

obtain accurate simulations of bird impacts on a flat plate (Kara 2011) . Due to the

difficulty in manufacturing an engine and the intricate computational modelling details

required, bird strike on such a component cannot be investigated during this research.

Explain why the text identifies a gap. What are its strengths andweaknesses?

Text 1 Text 2

Strengths

Weaknesses

What is critical analysis?

Page 8 of 10


9/10

Describe the features of a good quality state of the art report.

_______________________ ________________________

_______________________ ________________________

_______________________ ________________________

_______________________ ________________________

Structure of the state of the art report

Page 9 of 10

Rationaleor

design brief

Introduction ContextSet the scene

Critical analysisDescribe current state of research / technology

Summarise previous work done in the areaIdentify the limitations / problems of the research /

technology

Identify the gap in the knowledge

Explain how the project will overcome the gapExplain the possible solutions to the problems

eg. design solutions, design concepts

Research / design questionsProblems you will be addressing

Aims &objectives


10/10

Further considerations

Think about your audience

o who will be reading the state of the art report?

o You are trying to convince your audience that what you are doing is

important.o You therefore need to write persuasively. Examples of persuasive

documents include posters (UCAS, ILF), state of the art report andthe executive summary.

Attention to grammar, vocabulary, punctuation is essential

Language verb tense

References follow Harvard system

Structure link between sections

Presentation style

Evidence of proof-reading whole document

For more help, visit Wishees text / podcast on how to write a state of the artreport.

http://www.qmul.ac.uk/wishees/

Page 10 of 10
http://www.qmul.ac.uk/wishees/http://www.qmul.ac.uk/wishees/

SOTA Handodut3

Documents

Transcript of SOTA Handodut3