DEPARTMENT OF MECHANICS AND APPLIED COMPUTER SCIENCE
Faculty of Mechanical Engineering, Military University of Technology
00-908 Warsaw, Kaliskiego Street 2, Poland
phone: +48 261 83-98-49, fax: +48 261 83-93-55, e-mail: kmiis@wat.edu.pl




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Tadeusz Sendzimir Honorary Medal for Tadeusz Niezgoda
19.07.2013




A very nice event for our academic community took place during 14th Metering of Tadeusz Sendzimir Honorary Medal Knights on 19th July, in AGH University of Science and Technology in Cracow. Prof., D.Sc., Eng., Tadeusz Niezgoda, at the request of Association of Polish Inventors and Rationalizers, was granted a “Tadeusz Sendzimir Honorary Medal” for his contribution to design and implementation of new products of Polish arms industry. The medal was given by the President of Association of Polish Inventors and Rationalizers – D.Sc., Eng., Michał Szota and Prof., D.Sc., Eng., Zbigniew Kąkol – Vice-Rector for science of AGH University of Science and Technology. Prof. Niezgoda delivered a paper “Numerical simulations as a tool to help inventor”.


Presentation of the medal and commemorative diploma
(from the left to right: Prof. Tadeusz Niezgoda, President of Association of Polish Inventors and Rationalizers – Michał Szota, Prof., Zbigniew Kąkol)


Tadeusz Sendzimir medal was established on the occasion of the 10th anniversary of Association of Polish Inventors and Rationalizers founding. Engineer and inventor, Tadeusz Sendzimir, went into exile after the Second World War, where he developed a company specialising in design of machinery for metal treating. He owned 73 patents. He was one of the eminent engineers of Polish emigration. At the end of his life, he and his wife established “Sendzimir Foundation” which promotes the rules of sustainable development in Poland to date.


Prof. Niezgoda is delivering his commemorative speech


Every year, at the request of the chapter, National Council of Association of Polish Inventors and Rationalizers grants this honorary distinction to eminent technology creators, inventors and organizers for special merits for development of science and industry. The circle of medallists involves mainly professors of worldwide renown from well-known universities in Poland and overseas as well as industry leaders. Until now, Tadeusz Sendzimir Medal was granted to 257 eminent people from the world of science and technology as well as institutions merited for development of innovations.




Prof., D.Sc., Eng., Tadeusz Niezgoda’s paper

“Numerical simulations as a tool to help inventor”

Modelling and computer simulations constitute a pillar currently conducted research and engineering works linking a theory with experimental tests. It is more and more difficult to find a research area in which they are not the basic tool to help an inventor search for an innovative solution.

Development of modern computer-aided design systems, particularly computing systems, give almost unlimited opportunities in the area of simulating complex physical phenomena. Numerical modelling is, in its essence, a certain way to describe phenomena mostly connected with a description of material objects behaviour in order to understand them better. Understanding the laws covering behaviour of such an object enables prediction of its behaviour in different conditions, steering the object or creating new objects of narrowly determined required properties. Hence, the most popular of the computing method, the finite element method FEM, found its application to problems including:

  • spatial stress distribution tests,
  • investigation of constructions in which either there is no possibility to place measurement sensors or it is very difficult,
  • structure optimization,
  • displacements, strains and stress determination in structures and constructions
  • investigation of sophisticated supporting constructions in which there is no possibility to apply measurement apparatus or a large number of sensors,
  • research on the effect of explosion on a vehicle and people inside it,
  • in cases when investigations concern people, e.g. behaviour of a body during road incident (crash with other vehicle, hitting a barrier, etc.).

In the development process of models applied in structure analysis, it is possible to indentify several stages. The first one is to define the very problem. The next one is to describe this problem in the way enabling analysis with an available mathematical apparatus including a number of simplifications and various assumptions, among others, results of experimental tests in the form of empirical dependencies. In the end, the developed model is subjected to analysis and a validation process, and the obtained results are the basis to verify if the model reflects a given phenomena sufficiently.

Considering the accuracy of the obtained results, the most important stage is evidently the last element of the process, namely, model validation. Taking into account the above mentioned aims, for which the mode model is built, it seems logical to divide this task into two following separate problems:br />

  • verifying if all the procedures and calculations are error-free. In other words, verifying if an obtained result is formally correct,
  • verifying if the built model, after applying necessary simplifications and adopting all the assumptions, still reflects sufficiently a phenomena subjected to analysis.

The ultimate purpose of the process of model verification is an answer to a question if on its basis it is possible to draw conclusions on behaviour of a real object or a course of a real process.

The further presented cases of numerical modelling application for obtaining innovative construction solutions for an energy absorbing layered panel supporting a road barriers system, innovative railway wagon with a rotatable loading floor for intermodal transport of lorry semitrailers and pontoon cassette bridge of high mobility are evidences of an increasing importance of modern computing systems CAD/CAE for numerical simulation of complex phenomena.

Energy absorbing layered panels supporting a road barriers system are utensils, in design of which an increasing importance of numerical simulations is sought. Presently, in this field, there are applied real polygon crash tests conducted according to PN-EN 1317 standard. Unfortunately, these tests are time consuming and expensive, what really discourages producers to apply their capabilities. Additionally, a significant limitation of the experimental tests is, in this case, also necessity of possessing test stands equipped with catapults or rope drives, accelerating vehicles to desired velocities, as well as specialized devices (including high speed cameras, accelerometers) for measurement and registration of the courses. Uniqueness of an examination requires strong involvement so that one test was carried out properly and provided constructors and designers with as many data possible.


Energy absorbing layered panel supporting a road barriers system


Numerical investigations are becoming a highly efficient modern tool creating new possibilities for both producers and state roads administrators facing the problem of selection of the most suitable solution on a given section of the road. Numerical investigations not only can help at the design stage of devices of this type (due to rapidity, easiness and cost of investigating many options simultaneously, introducing modifications or testing new, not existing physically yet, solutions), but also can be used to conduct credible, numerical (virtual) crash tests.

An essential problem is not only participation of a man in a road incident but also his safety. The simulations conducted in Motor Transport Institute in Warsaw on so called “elephant’s scales” proved that passenger’s body weighting 99 km during the crash at 25 km/h interacts with mass equal to 2772 kg, at 40 km/h it is equal to 3960 kg, and in the case of a crash at 55 km/h the body acts as if it weights 5247 kg. These values help to realize the fact that an influence of the number and arrangement of passengers in the car should not be neglected since they doubtlessly influence the course of the road incident. Numerical modelling gives the same possibilities, therefore, investigations of a mutually coupled man – barrier – vehicle system is possible in different configurations of the elements of this system.

Owing to conducted numerical analysis it was possible to develop an energy absorbing layered panel supporting an existing road barriers system and improving both the safety of road users and vehicle kinetic energy absorbed by a barrier, as well as reduce damage caused by vehicle elastic rebound after hitting. It is especially important in the areas where the accidents are frequent and on curves of the roads

Other works carried out at Military University of Technology resulted in an innovative construction of a special wagon for transport of semitrailers of lorries. Owing to applying numerical modelling and carrying out complex numerical simulations it was possible to create a project of a 3Dwagon prototype with all installations and additional equipment.


Innovative wagon with rotating loading platform


The conducted multi-variant numerical analyses made it possible to design a wagon with a low undercarriage frame which meets the requirements of GB1 gauge and a rotating platform of the body with a reinforced structure of sideboards, the conducted numerical and strength analyses allowed the design of numerous functional solutions including: a central nod in respect to which the platform is rotated, stabilizers in the form of additional hydraulic supporters mounted under the lowered plate of the undercarriage and adapted to lift the wagon on the rails during loading and unloading the wagon as well as mechanisms responsible for extortion of rotational motion of the platform. Compared to other systems for intermodal transport, it has a number of advantages resulting from application of interesting solutions protected by both national and European patent applications. Utilization of the mobile wagon allowed the team to propose an innovative system of intermodal transport.

Another example of application of numerical modelling and simulations is construction of a mobile cassette bridge of regulated carrying capacity. The bride includes, in a closed space, folding pneumatic containers made of high strength material and resistant to adverse environmental factors. It obtains its regulated displacement through application of a pontoon (shells) filled with gas as a carrying element of a river module. The filling ratio of the pontoon determines carrying capacity of a single river module and the whole bridge.


Cassette pontoon bridge of high mobility


Development of an innovative structure of the module bridge crossing required satisfying extremely difficult conditions imposed by standards as well as conditions of their exploitation. It concerned, first of all, a necessity of providing relevant stiffness of the system, resulting from limitations connected with carrying capacity of the bridge crossing. An additional challenge was a necessity to apply a high strength air cushion providing, among others, accurate displacement, ballistic protection and many others. For these reasons, the design process required application of advanced techniques of numerical simulation. A detailed solution required application of static and dynamic global-local analysis.

The developed structure of the cassette pontoon bridge of high mobility is designed for both civil and military applications. It can be successfully applied to built bridge crossings or piers in case of a natural disaster or a local constraint resulting from, among others, temporary closing of bridges. The structure also enables replacing the damaged bridges through eliminating burdensome diversion or serve as temporary ferry for transportation of small mass objects, and its transport and preparation to usage is a simple operation without a necessity of applying a special equipment.

Summing up, it can be stated that progressive development of computer technology allows significantly wider application of a numerical simulations method, compared to previous years. Higher computer calculation powers gives an opportunity to create more complex numerical models and solve more and more difficult problems. Calculation methods and simulation tests applying numerical simulations thus become a more advanced and effective tool. It is worth pointing out a simultaneous development of experimental methods closely related to validation of numerical models and applying more advanced appliances coupled with a computer, which allow obtainment of more precise results. The modern more subtle methods, owing to which the experiment enters in new research areas, are also applied to research practise. Taking into consideration advantages and disadvantages of both the methods (i.e., experimental and numerical) and possibilities of their application, it can be concluded that both the methods complement each other and particularly are destined to “cooperate”.

The presented innovative solutions, the development with a significant usage of numerical modelling, aroused vivid interest both in Poland and overseas, as illustrated by numerous medals and distinctions during world fairs and contests of inventions as well as by both Polish and international patents and patent applications.


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