Monday, 25 June 2018

Training weeks are full of adventures and experiences

I would like to write about interesting training weeks that we had so far within INFRASTAR
We had our Third training week recently at Aalborg University, Denmark, and we performed the previous ones at EPFL (Lausanne, Switzerland) and BAM (Berlin, Germany). 

Apart from the lessons that I have received during our training weeks in different areas of engineering and career development, having the opportunity to visit different labs, structures, materials, and advance technologies in civil engineering domain, gave a me a great insight and experience about what I am currently doing. 

We had our first training week in BAM, Berlin, which is the Federal Institute for Materials Research and Testing in Germany. During this training week, we visited their testing laboratory for concrete structures. They are developing some new tools and methods of none-destructive testing for concrete structures, and we had the chance to get familiar and work with some of their sensors during our visit. 

During the second training week in EPFL (École polytechnique fédérale de Lausanne), we had the chance to get familiar with a new type of material for construction that is a relative of concrete with different properties and it is called UHPFRC (Ultra-High Performance Fibre Reinforced Concrete). We also visited some structures that have already been built using this new type of concrete. 

Finally, we have visited a testing wind farm in Aalborg within our third training week in Aalborg University. Since I was always interested in renewable energy and sustainable development, It was the most amazing experience for me among all visits that I have had so far. We could learn about the recent technologies in the area of wind energy and see some of them working in the wind farm. 

In the end I would like to thank my program (INFRASTAR) that has provided us this amazing training in different and interesting places. 

Thanks a lot for reading this post, 

Training week 1, BAM 

Training week 2, EPFL

Training week 3, Aalborg

Tuesday, 22 May 2018

What is better than having another Marie Curie PhD at your office?

 I would like to devote this post to my colleague Barbara Heitner who is a PhD in TRUSS ITN under Marie Curie actions.

When you want to start a new career particularly when you need to move to another country, in the beginning, you always need some people to assist you with different issues to be able to stand on your own. Apart from the other great members of Phimeca, I would like to admit that I am so lucky to have Barbara as my colleague who has started her PhD one year before me in Phimeca and paved most of the roads before me. Not only for my research and work issues, she is also a great help to tackle personal problems.

With respect to the work, when your work situation and contract is different than other colleagues in the company you may go through different administrative procedure than others and in some cases it might be very boring and time consuming. As Barbara has already started her work before me as Marie Curie PhD at Phimeca, it made my recruitment procedure much easier and more straightforward. Also, it is always a great change when you start working in a company after university and it is not so easy for many people to easily get used to the new environment. It is much easier to adapt to work in a company when there is someone else in the workplace who has the same situation as yours.

In the other hand, since my research project and Barbara's are in the same domain, when I am facing different questions, she is the first person who hears them. Thank to the Phimeca's research team and Barbara, I could make a great progress in structural reliability analysis, probabilistic modelling, and programming in Python.

Apart from being colleagues Barbara is a great friend too. I appreciate her helps regarding my personal life as well. She made it easier for me to get used to live in  Clermont-Ferrand, France. Sometimes when I needed a company to discuss about different topics and maybe having a drink in the evening she was always there.

Since the next two weeks will be our final weeks that we spend together in Phimeca, by this post I would like to appreciate her help and support and I want to say that I was so lucky and glad to have her as my colleague.

Thank you very much for reading this post.

Me and Barbara after preparing the Christmas tree for 2018 in Phimeca

Thursday, 5 April 2018

A short introduction on Meta-Modelling and Kriging

In many branches of science and particularly Engineering, there are lots of complex physical models that are very hard to evaluate, or in the other hand there might be some data available that there is no physical model to describe them. Regarding to these issues, Surrogate models or Meta-models provide a very appropriate tool to be able to address such problems. Meta-models can replace a very complex mathematical model which is very expensive to evaluate with a simpler model, therefore,  applying available numerical methods on the meta-model will be much cheaper. Also, for those data that there in no model available, one can say that surrogate models are the only remedy. 

Having a good design of experiment is adequate to prepare the meta-mode and this is a great advantage for this approach since design of experiment is a small set of realisations of input variables and the corresponding output of the complex original model. Hence, the effective cost of meta-model goes for the choice of design of experiment. 

There are different types of meta-modelling such as functional basis methods, Gaussian regression and spectral methods. Choosing among these methods depends on the quality of the method and their ability to address high dimensional problems with a good accuracy. 

Gaussian process regression (Kriging) 

Among different methods of meta-modelling Kriging meta-modelling or Gaussian process regression is one of the most interesting methods. Kriging metamodeling has been formulated by a French mathematician George Matheron around 1963 and he named the methodology after a South African mining engineer D. G. Krige who applied this methodology for the first time in geo-statistical problems. In fact, Kriging is the best linear and unbiased prediction of the unknown value of a random function M at any voluntary location. 

Kriging meta-modelling is based on this idea that any physical model can be formulated by combining a regression model with a stochastic process. By using the design of experiment, regression model tries to find the general trend of the original model and stochastic part reduces the distance of the approximation by regression and the points in design of experiment to zero. Different steps of Kriging is illustrated in Figure 1. 

Kriging meta-models can provide a very helpful tool in the area of structural reliability analysis. There are different methods developed out of kriging for reliability analysis such as EGRA, Independent EGO, Mixed EGO, AK-MCS, etc. ((H. Zhen & D. Xiaoping, 2015), (W. Fauriat & N. Gayton 2013 ), (B. Echard et al. 2011)). 

Figure 1 Kriging modelling steps 

Thursday, 1 February 2018

One year in France

Since I am about to celebrate the first anniversary of my new job in France. I would like to devote this post to some of my living experience in France in a very short version. 

Living in another country, especially in the beginning, is like having lessons for every day in which even a small kid can be your teacher while you are learning their language. Of course, this learning process in not only about the language, you can learn a lot from people about their behaviour in different situation such as public transportation, classrooms, pubs, shopping, etc. In my opinion, when you want to know more about a country or a culture, the best way is to live among locals. 

When it comes to France, most of us can guess about different things that is famous in this country, however, depending on the person the first guess might be different since there are a lot of good stuff in France. In my own case I was always wondering about French wine and cheese. I did not have  any idea that consuming French cheese might be very addictive but gladly I was able to control myself against all those tasty cheese to become an addict. Although, French wine is super, beer is very expensive. I think they have intentionally increased the price of beer to persuade people to spend more on wine :)

During the last year I learnt a lot in this country. I found French people so polite while facing strangers especially when they are going to do something and that might be different in their friend's culture, so they ask first to make sure if it is not gonna be offensive for them. But, the most interesting characteristics that I realised about French people is that they expect you to learn their language very fast, however French is a very difficult language. They easily become tired of speaking English even if they are very fluent in English. 

In the end I would mention that, if one  wants to enjoy his/her life in France, there are too many things you can do. There are a lot of beautiful regions and cities in France to visit with their own specialities, also, there are a lot of good facilities to study, to do sport, music, etc. 

Thanks for reading this post,
Stay tuned for next one :)

Monday, 27 November 2017

A Great Opportunity to Learn TeamWork

Infrastar PhD s during second training week
Teamwork is a matter of practice and patience. 

Once you start working as a Marie-Curie PhD student, most probably, you will find yourself working with different labs, companies, universities, and research centres having several supervisors from those places. You might have monthly meetings with five or six people to present your improvement and results, therefore, it is necessary to improve your teamwork skills to be able to adapt yourself with such a working conditions.
In the other hand, there will be some other PhD students under the same Marie-Curie program which they can be considered as your classmates. They normally live in another city or country but since PhD topics are somehow related, there is a great opportunity of teamwork and developing ideas together as well. Mari-Curie team allocates some training weeks in which all PhD s under the same program gather together and share their ideas and try to find a way to cooperate with each other. 

As a Marie-Curie PhD student I would like to tell you that, not everyone find it easy to work under this highly team-basis conditions. It may look very interesting in the beginning, however, it is amazing, but I would say that seriousness and practice are very important factors to gain this teamwork skill. 

In the picture above you can see my classmates and some of our supervisors, however, we are not really in the same school and in the same class. 

Stay tuned for next post :)

Wednesday, 15 November 2017

Maintenance strategies: Preventive and Corrective

Among different types of maintenance strategies that were introduced before, preventive and corrective maintenance can be called the main strategies. 
Preventive maintenance actions are generally referred to those actions that are applied on the structure regularly and that try to maintain the structure from unexpected failures and keep it working.  Preventive maintenance defers the degradation process, hence, it extends the time needed for corrective actions and operational capacity will be increased. In the other hand, because they are performed timely and based on a routine, therefore, less large scale repairs are required. In practice, a preventive maintenance schedule may include things such as cleaning, lubrication, oil changes, adjustments, repairs, etc.

Corrective maintenance is another strategy which will be applied on a structure when a flaw is detected. The purpose of the corrective maintenance is to restore the operational capacity of the structure to an acceptable level. according to the importance of the flaw a corrective action can be applied immediately or deferred for a certain time. There are different types of actions included in corrective maintenance and the application of each depends on the defect situation. In worst case scenario replacement of the component of structure is the final solutions. 

Maintenance strategies, RD/GD-210, 2007 

Stay tuned for the next post ;)

Monday, 2 October 2017

Structural Maintenance Planning

Maintenance planning for structures, for a long time, was a concept of keeping the structure in a good shape, hence, it can perform its expected duties. Yet, because of financial and physical limitations in the old definition, operational managers had to provide a more comprehensive description for maintenance of structures. Hence, a more professional definition for structural maintenance would be defined as: "Total technical activities in the component level connected to each other and economically balanced, in order to keep or get the structure in such a condition that it can accomplish its duties for a certain period of time with sufficient reliability, availability, serviceability, and durability” Toorn (1996).  

According to the new definition, some targets such as maintenance and managerial targets could be identified. Maintenance targets try to assure an adequate level of reliability, availability, etc. and managerial targets mainly aim to minimise the associated maintenance costs. These targets will provide some tools and indicators which are so helpful to mathematically formulate the problems in structural maintenance planning. For instance, Annual reliability index can be used as an indicator if the purpose of maintenance planning is to reach a certain level of reliability or maximise it as affordable as possible.

Structural maintenance can include different kinds of actions which regarding to the type of action and their influence on the degradation process can be divided into four categories:
1- Preventive maintenance, 2- corrective maintenance, 3- observational maintenance, and 4- non-inspection maintenance. 

Differences between these categories will be explained in next posts.    
Bridge maintenance: repainting (Photo: Fox Photos / Getty Images)

Training weeks are full of adventures and experiences

I would like to write about interesting training weeks that we had so far within INFRASTAR .  We had our Third training week recently at...