Tuesday, December 20, 2011

...and the Award Goes to...

My research is among the candidates for a prestigious award. Let's cross our fingers and wait!

Thursday, November 17, 2011

New Scientific Article by Korkmaz et al: Configuration of Control System for Damage Tolerance of a Tensegrity Bridge

In a fresh article published by Advanced Engineering Informatics, I and my co-authors are demonstrating how to configure an active control system for a tensegrity bridge. Here is the abstract and the keywords of this study:



Abstract

Tensegrity structures are spatial, discrete, and lightweight structures that are composed of struts in compression and pre-stressed cables. Stability is provided by the self-stress state between elements independently of external actions. Tensegrity structures are attractive due to their potential for deployability, ease of tuning and high precision control. Since tensegrity structures have highly coupled behavior, placement of actuators is a primary concern when designing active control systems. This study investigates the active control performance of cable members of a tensegrity bridge. The actuation efficiencies of cable members are evaluated through a multi-criteria approach. The configuration of the control system is thus identified through outranking candidate active members. A multi-objective damage tolerance strategy is then proposed and optimally directed control solutions are identified using stochastic search. Case studies for several damage scenarios are examined to validate results. The most efficient active cable configuration is compared with that needed for deployment. This study is divided into two phases. After the description of a 16 m-span tensegrity bridge, optimally directed locations of active cables are determined in the first phase. Secondly, a procedure to ensure damage tolerance of the structure is proposed. The multi-objective self-repair procedure provides damage tolerance minimizing both maximum deflections in the structure and stresses in the structural members. Results indicate that the control strategy for deployment is a near-optimal solution for damage tolerance. The proposed methodology is applicable to a range of complex active structures.

Keywords: Structural control; Optimum active control; Control efficiency; Damage tolerance; Pareto optimum; Multi-criteria decision making

Full article can be accessed using the following DOI: http://dx.doi.org/10.1016/j.aei.2011.10.002

Sunday, October 9, 2011

A Cool Tool: tensegrity

Recommended:

A brief introduction to the applications of tensegrity: Beading Crimp Tubes and Monofilament by Phil Earnhardt

Wednesday, April 6, 2011

Engineering Education in Turkey

2011 QS University Rankings are now available:

Civil & Structural Engineering Rankings
Chemical Engineering Rankings
Electrical Engineering Rankings
Mechanical, Aeronautical & Manufacturing Rankings
Computer Science & Information Systems Rankings

As expected, MIT tops in all subject rankings. On the other hand, despite all the buzz Turkish universities create in national media, no Turkish university except Istanbul Technical University (ITU) is listed in top-200 list. ITU is ranked

101-150. in Civil & Structural Engineering
101-150. in Chemical Engineering
151-200. in Electrical Engineering
151-200. in Mechanical, Aeronautical & Manufacturing

Although scientific research has become utterly more productive over the past decade in Turkey (please see the relevant statistics here), the gap between the quality of Turkish universities remains wide. Thanks to the booming economy and changing socio-cultural system, many top-notch Turkish researchers prefer to go back to Turkey. This potential has to be harnessed in a systematic way.

It would be too naive to expect ITU and a couple of other decent Turkish universities, such as Bilkent University and Sabanci University, to educate the huge army of good engineers that the quickly growing economy desperately needs. Time and again, concerns are raised on the quality of the vast majority of Turkish engineers, and for good reason. Let's face it - Among the ~170 Turkish universities, only ITU is listed in the engineering subject rankings! Turkey has potential for more, uhm, better science...

Thursday, March 31, 2011

New Scientific Article by Korkmaz et al: Determining Control Strategies for Damage Tolerance of an Active Tensegrity Structure

My new scientific article is published online by Engineering Structures. Some folks have been asking about this study since last year. Here is the abstract of the paper:


Tensegrity structures are spatial, reticulate and lightweight systems composed of struts and cables. Stability is provided by a self-stress state between tensioned and compressed elements. Tensegrities have received interest among scientists and engineers in fields such as architecture, civil and aerospace engineering. Flexibility and ease of tuning make these systems attractive for controllable and adaptive structures. However, tensegrities are often prone to difficulties associated with meeting serviceability criteria and with providing adequate damage tolerance when used as civil engineering structures. This paper extends research on active control of tensegrity structures to study self-repair of a tensegrity pedestrian bridge that is damaged. Self-repair is intended to meet safety and serviceability requirements in case of cable damage in the pedestrian bridge. Intelligent control methodologies that implement stochastic search with active member grouping are proposed. Case studies for several damage scenarios are presented to show the effectiveness of the methodology. Results from simulated damage scenarios show that self-repair can be successfully performed with a minimum number of active members leading to a reduction in control complexity.

Keywords: Tensegrity structures; Active control; Self-repair; Damage tolerance; Stochastic search

Full paper can be accessed using the following DOI: http://dx.doi.org/10.1016/j.engstruct.2011.02.031.

Friday, February 4, 2011

Biomimetics in Distributed Computing


A "traditional" application field of biomimetics is computer science. Computer scientists have been using biomimetic approaches in subfields such as stochastic search. A new study by Yehuda Afek et al. aims to provide simple and efficient algorithms in the subfield of distributed computing using a technique inspired from the nervous system of the fly. The original paper can be accessed here.

Photo by Valter Jacinto

Wednesday, February 2, 2011

Coming Up: a 1.6m-Span Tensegrity Bridge

A 1.6m-span tensegrity bridge model is currently under construction at EPFL. Timber struts and nylon cables are used as compression and tension members in the lab structure, which will be used for damage-tolerance research.

Tuesday, January 25, 2011

Peer Review vs Twitter Verdict

An article by Apoorva Mandavilli questions a new trend in academia: peer-review via online social networking sites and blogs. The following two instances are given to illustrate the emerging online peer-review:
  1. Sebastiani, P. et al. Science doi:10.1126/science.1190532 (2010).
  2. Wolfe-Simon, F. et al. Science doi:10.1126/science.1197258 (2010).
In both examples, the papers are ripped apart online. Although disadvantages of the current peer-review system decrease productivity, I do not find the new unruly, unstructured and often anonymous procedure constructive. As Wolfe-Simon mentions, "Any discourse will have to be peer reviewed in the same manner as our paper was, and go through a vetting process so that all discussion is properly moderated". Hard-earned scientific information should not be wasted with chit-chat level "scientific commentary" via Twitter.

Tuesday, December 7, 2010

Times Higher Education and Reuters Rank EPFL Top in Europe

Swiss Federal Institute of Technology (EPFL) is ranked first in Top European Universities in Engineering, which is prepared by Times Higher Education and based on the publication and citation performance of universities. Data is provided by Thomson Reuters.More information is available at the following link:

http://www.timeshighereducation.co.uk/story.asp?sectioncode=26&storycode=414302&c=1

Wednesday, December 1, 2010

Zero-Emmission Walking Vehicle

Yet another biomimetic legged vehicle: Mondospider. Zero emission!






























For more information, please visit the website dedicated to this project:  www.mondospider.com.

Tuesday, November 30, 2010

Biomimetic Robots

Robotics is an application field of structural control. Here are two videos featuring two biomimetic robots developed by Boston Dynamics:




Friday, November 12, 2010

Leiden Ranking 2010

Leiden Ranking 2010 is revealed. According to the size-independent, field-normalized average-impact based methodology, the top 5 universities in Europe are listed as follows:

1. Swiss Federal Institute of Technology, Lausanne (EPFL)
2. Swiss Federal Institute of Technology, Zurich (ETHZ)
3. University of Cambridge
4. University of Oxford
5. University of Lausanne (UNIL)

Further information is available here.

Friday, November 5, 2010

Popularity of Civil Engineering (Revisited)

The video below is part of an effort by The Institution of Civil Engineering (UK) to let people know a little more about the profession of civil engineering:

Thursday, October 28, 2010

Tensegrity mechanisms are used in a number of applications. Yet another tensegrity application is coming up: headphones. Teague 20/20 headphones make use of flexibility and self-stress mechanisms of tensegrity to make it automatically form to the user's head. The designer of the headphones is Dana Krieger.









More information is available at http://www.teague.com.

Tuesday, October 26, 2010

Popularity of Civil Engineering

CNN Money (a service of CNN, Fortune and Money) published the "best jobs in America". Among the 100 job titles listed, civil engineering is ranked only 6th (2nd among engineering disciplines). It is highlighted that huge construction projects and aging infrastructures are bolstering demand for civil engineers. Median salary of civil engineers is noted to be $80,000.

Why does the society not appreciate the profession of civil engineering (more generally, engineering) as much as some other 5 professions?

I believe that there is a serious image problem of (civil) engineers in the society. (Civil) engineers trained at universities of low quality give an impression that being a civil engineer is an easily achievable goal. On the other hand, almost all engineering students of good universities could be accepted to the departments of which graduates are more appreciated. Let's have a closer look at them:

1. Software architect
2. Physician assistant
3. Management consultant
4. Physical therapist
5. Environmental engineer
6. Civil engineer

A significant amount of software architects and management consultants are engineers. What about the two healthcare professions? All (civil) engineers that are trained at decent universities had the choice to go to any department. They did not choose to do it due to several personal and some common reasons (e.g. in some countries, only engineers have had the image of "smart people").

The image of being #6 is ascribed to civil engineers for a reason. We need to eradicate this bad image that bad "engineers" have given to the society.



Wednesday, October 20, 2010

Galloping Gertie

Engineering education matters... Here is one of the numerous disasters resulting from engineering mistakes:


The Tacoma Narrows Bridge (Gallopin' Gertie (!)) was opened in 1940 in Washington. There was apparently a problem in the design of the bridge:
Once the bridge was built and it was recognized that "there was a problem", the engineers attempted to control the bridge passively using hydraulic dampers. However, the effectiveness of the hydraulic dampers was nullified since the seals of the units were damaged when the bridge was sand-blasted before being painted.


Aeroelastic fluttering induced the failure of the suspender cables 5 days after Prof Frederick Burt Farquharson (University of Washington), proposed to give a more aerodynamic shape to the transverse section of the deck by adding fairings or deflector vanes along the deck, attached to the girder fascia, the bridge collapsed due to 64 kmh wind.


It took 10 years to build a new bridge due to material and labor shortages as a result of the involvement of the United States in World War II. The new replacement bridge was opened to traffic on October 14, 1950. Here is a panorama of the bridge, which is still in service:




Source: Wikipedia, Youtube

Friday, September 3, 2010

European Group for Intelligent Computing in Engineering Workshop 2011

Yet another meeting to present results of intelligent computing research: European Group for Intelligent Computing in Engineering (EG-ICE) Workshop 2011.  More information about the program, deadlines and the committees of the workshop can be found under the following link:

http://www.utwente.nl/ctw/eg-ice/People/

Thursday, August 12, 2010

2011 ASCE International Workshop on Computing in Civil Engineering

                                                                Click image to enlarge


International Workshop on Computing in Civil Engineering will take place in Miami next year. It could be a good opportunity to present results on the role of informatics in adaptive structures.

Monday, August 9, 2010

An Interdisciplinary Research Field: Active Tensegrity Structures

Research into “active tensegrity structures” has been carried out since decades by aeronautical engineers, civil engineers and mechanical engineers. Keeping in the mind the productive nature of interdisciplinary work, I believe that the interaction between research groups composed of researchers from merely one of these categories should be enhanced. Ultimately, an ideal research group working on active structures would comprise civil engineers, aeronautical engineers, mechanical engineers and computer scientists. Also, there is a gap between the research conducted in Europe and the research conducted in the US. Most of the researchers in the field of “active tensegrity structures” are civil engineers in Europe (e.g. Ian F.C. Smith, RenĂ© Motro, Simon Guest*). On the other hand, almost all of the scholars working on active control of tensegrity structures (e.g. Robert E. Skelton, Cornel Sultan, Hillary Bart-Smith) are from aeronautical or mechanical engineering field. Also, other aspects of tensegrity structures are studied by medical doctors (e.g. Donald Ingber). Collaboration among these groups is very important in the context of transatlantic research cooperation, as well. Therefore, it is worth to step up efforts toward such collaboration.

*Simon Guest is not a “civil engineer” but an “engineer” since University of Cambridge does not award any other engineering title.

Saturday, July 17, 2010

When Scientists Sin

After The Fraud Epidemic (page 20), yet another article on fraud, deception and lies in scientific research: When Scientists Sin, by Michael Shermer.

Wednesday, July 14, 2010

Smart Structures for Undergrads?

The concept of "smart structures" has been implemented in aeronautical engineering for a long time. However, most of the civil engineering students are hardly aware of this terminology. In most higher education institutions, subjects such as adaptive structures, active structures and smart structures are considered to be "luxurious".

At Lehigh University Department of Civil and Environmental Engineering , Dr Yunfeng Zhang offered a "Smart Structural Systems" course to undergrad and grad students during the Spring 2006 semester. Here is how it went!

Smart Structure at Swiss Federal Institute of Technology, Lausanne

Saturday, May 8, 2010

"Uniform Material Law: Extension to High-Strength Steels" by Sinan Korkmaz

My new book is published: Uniform Material Law: Extension to High-Strength SteelsThe book presents a refined methodology to predict fatigue life of high-strength steels. It is intended to be a useful reference for mechanical and structural engineers as well as researchers of related disciplines.

Saturday, April 10, 2010

Tensegrity Wiki: The Encyclopedia of Tensegrity

There is an online gathering point for people working on tensegrity:

http://tensegrity.wikispaces.com/

Highly recommended!

Thursday, March 25, 2010

World’s Largest Retractable Aluminum Dome

Openaire, a Canadian company is currently building the largest retractable aluminum dome in Donetsk, Ukraine. Aluminum is not a commonly used material in civil engineering. However, its certain characteristics such as corrosion resistance could be advantageous in some harsh environments. Below is the press release explaining the project:

Donetsk, Ukraine will soon boast the largest aluminum-domed indoor waterpark in the world. Scheduled to open in the fall of 2011, the Royal Marine Aquapark dome is the creation of Oakville-based OpenAire, which specializes in totally unique structures that incorporate retractable roofing systems. OpenAire has created retractable roofing enclosures for water parks, hotels, community centers and other commercial applications.

“At 26m / 86’ high and 85m / 278’ in diameter, it’s the largest free-standing aluminum dome structure in the world,” says OpenAire president Mark Albertine, “And the unique retractable design makes it the first park of its kind. There is simply nothing else like it.”

The waterpark had initially been planned as a steel/polycarbonate structure with a fixed dome. “Things were already in the planning stages when we were brought on board,” says Albertine. “When the developers heard about OpenAire, they loved the idea of a retractable roof. To them, it opened the park up to a whole new world of possibility.”

There are great benefits to OpenAire’s approach of using aluminum for water parks. Unlike steel, aluminum doesn’t corrode, doesn’t need to be painted, withstands chlorine, and requires zero maintenance. In addition, the retractable roof offers flexible, year-round enjoyment. People don’t want to be inside on a beautiful day; opening the roof instantly transforms it into an outdoor facility, giving users the best of both worlds. Plus, opening it up to outside air helps reduce
dehumidification costs for water facilities.

“It will be a gorgeous, light-filled space that takes advantage of the outdoors whenever possible,” says Deborah Baker, OpenAire COO. “Families will love being able to get a break from the cold in winter – and feel the sun on their faces in the warmer months.”

The Royal Marine is a joint venture between the City of Donetsk and private sector investors. The Royal Marine is OpenAire’s second Ukrainian project. The company previously built a retractable skylight for the Terminal Water Park in Kiev-area Brovary Park, the country’s first major indoor water park. In the Donetsk water park, OpenAire’s role has been more significant, with the company providing the entire design and manufacture of the retractable structure.

A computer animation of the Royal Marine Aquapark is available here. For further information, please visit the website of the company at www.openaire.com.

Tuesday, January 26, 2010

Tensegrity Bridge in Washington


Wilkinson Eyre Architects proposed a tensegrity for the National Building Museum in Washington. According to the architectural firm, "The bridge is to be constructed from a network of glass tubes acting as compressive elements and joined together by cables in a ‘tensegrity’ structure. The underlying geometry is based on a series of tetrahedral cells, replicated numerous times to accumulate a visual mass capable of asserting itself within the extraordinary scale of the museum’s courts while remaining essentially light."

Tuesday, January 12, 2010

Increased Creativity in Research

I have come across Craig Loehle's paper called "A Guide to Increased Creativity in Research--Inspiration or Perspiration?", which could be very useful for the purpose of increasing research creativity. I believe that it can impact researchers' short- and long-term research ambitions. It can be accessed here .

Monday, January 11, 2010

Religion-Biomimetics




I am thinking about links between (any kind of) religions and biomimetics. Nature-worship may have influenced design processes. For instance, Gaia philosophy is based on that living organisms on a planet will affect the nature of their environment in order to make the environment more suitable for life. Buckminster Fuller has been credited as the first to incorporate scientific ideas into a Gaia theory, which he did with his Dymaxion map (Fuller map) (see the photos above) of the Earth.

Any ideas?


Source: Wikipedia, www.bfi.org

Monday, December 21, 2009

World's First Bionic Finger

A West Lothian-based company, Touch Bionics, announced the commercial launch of ProDigits. ProDigits is claimed to be the first powered bionic finger for people with missing digits (see the videos below). Detailed information is available here.






Wednesday, December 9, 2009

Biomimetic Civil Structures




A way of creating biomimetic civil structures is integration of methodologies that allow civil structures to adapt to the alterations in their environments by using self-diagnosis and self-repair techniques. Ian F.C. Smith brings together active control and biomimetics in "Control Enhancements of a Biomimetic Structure", which is published in June, 2009. Full paper can be accessed for free under the following link:
* Figure by Ernesto Bueno (Pear Biomimetics Project)


Wednesday, November 18, 2009

Floating Structures

The interview with Prof. Ian F.C. Smith, which was published in Reflex (science and technology magazine of EPFL) in September 2008, can be accessed at the 73th page of the pdf file under the following link:

http://www.reflexmagazine.ch/pdf/Reflex_n5_EN.pdf

Friday, November 6, 2009

Golden Boy's Heartbeat


Structural health monitoring (SHM) is an integral part of active structures. According to Daniel Barageas from the French National Aerospace Research Establishment (ONERA):

“SHM aims to give, at every moment during the life of a structure, a diagnosis of the state of the constituent materials, of the different parts, and of the full assembly of these parts constituting the structure as a hole. Thanks to the time-dimension of monitoring, which makes it possible to consider full history database of the structure, and with the help of usage monitoring, it can also provide a prognosis (evolution of damage, residual life, etc.)”.

SHM is used at a variety of structures. Aircrafts and bridges are two of the typical structures at which SHM is used commonly. On the other hand, there are also some “uncommon” fields of SHM usage. In Monitoba, Canada, an SHM system is installed inside a statue: the “Eternal Youth (Golden Boy)”. According to Dr. Mufti, the SHM system for the Golden Boy comprises four types of gauges: accelerometers, electric resistance strain gauges, fiber optic strain gauges, and thermocouples. The internal stress, vibration, and inclination of the structure can be monitored and its response to loading can be examined by using these sensors. At the central control site, located at ISIS Canada SHM Lab in Winnipeg, an application program on the data server is continuously running to subscribe the data from the remote site. The new data are transferred and analyzed every 5s. Currently, around 1GB of data per day on the Golden Boy is reported. A software program uses statistical analysis to sort through and interpret the data. If data patterns remain basically the same, the software does not store the data. Data are stored when the patterns change significantly, and researchers are notified if something completely new happens.

Source: The Monitor

Thursday, October 29, 2009

Academic Ranking of World Universities 2009

Academic Ranking of World Universities (ARWU) in Engineering/Technology and Computer Sciences - 2009 has been revealed. As can be estimated, Massachusetts Institute of Technology (MIT) is the best in the world and Swiss Federal Institute of Technology (EPFL) is the best in Europe. Further information is available on the official website of ARWU:

http://www.arwu.org/ARWUFIELD2009ENG.jsp

Monday, October 19, 2009

Clustered Actuation

According to K.W. Moored and H. Bart-Smith:

"Clustered actuation exploits the existence of cable elements in a tensegrity structure by allowing cables to be run over frictionless pulleys or through frictionless loops at the nodes".

Clustering of active cables has its strengths and weaknesses. If the active cables are clustered, the damage in one cable leads to greater displacements since all cables in the same cluster go slack. On the other hand, the disadvantages of embedded actuation such as added mass and cost, increased control complexity and energy consumption mean that grouping of active cables is preferable.

I am currently working on self-repair of a tensegrity bridge by means of clustered actuation. This is a promising subject, which has the potential to provide more efficient structures.

Reference: K.W. Moored and H. Bart-Smith, "Investigation of clustered actuation in tensegrity structures", 2009

Tuesday, October 13, 2009

Is The Kurilpa Bridge Safe?

There is a controversy between politicians on safety of the Kurilpa Bridge:

http://www.abc.net.au/news/stories/2009/06/17/2600744.htm

Some people even deemed the project scandal:

http://www.news.com.au/couriermail/story/0,27574,25652724-3102,00.html

However, these discussions are not to be taken seriously since they are based on speculations of non-engineers.

Largest Tensegrity Bridge in The World

Tensegrity "Kurilpa Bridge" was opened on October, 4. The solar-powered Kurilpa Bridge provides an environmentally-friendly and enjoyable walking and cycling pathway to the city from South Brisbane. The structure is 425m long and more than 1050 people were employed on the project. It is expected that 36500 people will cross Kurilpa Bridge each week. Here are some videos of the bridge in function:



Friday, October 9, 2009

The Robot Scientist Adam

The Computational Biology research group at Aberystwyth University developed a "Robot Scientist": Adam. According to King et al, "Robot scientists are a natural development of the trend toward ever-greater computer involvement in science. They are physically implemented laboratory automotion systems that apply techniques from AI to automatically execute cycles of scientific experimentation." Adam is claimed to be fully automate microbiological experiments. Detailed information can be obtained via the following link:

THE-QS World University Rankings-2009

The latest THE-QS university rankings have been revealed:

http://www.topuniversities.com/university-rankings/world-university-rankings/2009/results


Here is a link to the engineering/technology rankings:

http://www.topuniversities.com/university-rankings/world-university-rankings/2009/subject-rankings/technology

Saturday, September 19, 2009

Artificially Intelligent Structures

According to Patrick H. Winston:

“The engineering goal of artificial intelligence is to solve real-world problems using artificial intelligence as an armamentarium of ideas about representing knowledge, using knowledge, and assembling systems."

and

"The scientific goal of artificial intelligence is to determine which ideas about representing knowledge, using knowledge, and assembling systems explain various sorts of intelligence.”

Interest in artificial intelligence has been great since mankind envisaged robots. On the other hand, artificial intelligence methods are generally not associated with structural engineering applications. However, intelligent control methodologies such as self-diagnosis, self-repair and learning could be integrated into structural systems to provide innovative solutions that can also be applied to a range of other systems. We, EPFL Applied Computing and Mechanics Laboratory researchers, are going for a deployable tensegrity bridge that is able to take self-repairing actions thanks to an integrated active control and reasoning system. We believe that this research will be an important cornerstone toward the ultimate aim of intelligent structures.