Available online at ScienceDirect. Procedia Engineering 136 (2016 ) 21 27

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1 Available online at ScienceDirect Procedia Engineering 136 (2016 ) The 20 th International Conference: Machine Modeling and Simulations, MMS 2015 Prognosis supercomputer modelling of welded structures behaviour under dynamic loads Kirill Klimau a, *, Sergey Medvedev a a United Institute of Informatics Problems of the National Academy of Sciences of Belarus, Surganov Str. 6, Minsk, Belarus Abstract Principles of constructive and technological design, advanced supercomputer modeling of welded structures under dynamic loads were developed. The results of the experimental computational verification of the proposed approaches are presented. New themes of investigation and production work are pointed out The Authors. Published by by Elsevier Elsevier Ltd. Ltd. This is an open access article under the CC BY-NC-ND license ( Peer-review under responsibility of the organizing committee of MMS Peer-review under responsibility of the organizing committee of MMS 2015 Keywords: welded construction; finite element model; LS-DYNA; stress-deformed states; supercomputers 1. Introduction The competition in the markets of machine-building production stimulates search and progress of methods of design and creation of welded designs with predicted operational properties. In own publication it was noted that there are problems at design of rational options of welded designs by experts non welders. There are some reasons of these problems: 1) the engineers of departments of the chief designer who don't have educations of the engineer-welder aren't familiar with features of constructive and technological design; 2) in systems of geometrical modeling and the finite element analysis not enough attention to the processes reflecting influence of consequences of technological processes of welding on a resource and the bearing ability of the welded constructions working at variable loadings is paid; * Corresponding author. Tel.: ; fax: (375 17) address: klim@newman.bas-net.by The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license ( Peer-review under responsibility of the organizing committee of MMS 2015 doi: /j.proeng

2 22 Kirill Klimau and Sergey Medvedev / Procedia Engineering 136 ( 2016 ) ) the growing productivity of personal computers is insufficient for calculations and modeling of difficultly structural welded designs with a large number of the welded shortly seams located in space randomly; 4) there isn't enough specialists welders owning modern methods of computer modeling, the analysis and optimization by means of the settlement finite element systems who worked on supercomputers, grid-networks and clouds. 2. Chapter In this article the measures capable somewhat to overcome the designated reasons are offered. Means of fight thus: 1) the principles of constructive and technological design of welded designs of N.O. Okerblom [1], in the environment of high-performance supercomputer calculations; 2) the integrated techniques of forecasting of residual tension and deformations of the welded designs made by arc ways of welding steels ordinary quality and low-alloyed. In work of Japanese experts of 2007 [2] the scheme of force loading of vicinities of a welded seam at its cooling to room temperature is offered and verified (Fig. 1. This work confirmed justice of similar approach of one of authors of this article in 2001 [3, 4], (Fig. 1. Existence in the cooled-down welded seam of zones with tension equivalent to a fluidity limit, is known in literature on welding. region instant expansion region instant compression Fig. 1. the scheme of force loading of a welded seam; the scheme of force loading of a welded seam and it s vicinities with result.

3 Kirill Klimau and Sergey Medvedev / Procedia Engineering 136 ( 2016 ) Fig. 2. The stretching stress in the cross section of a butt seam. The direction of welding Fig. 3. Device with an hour head for definition of residual deformations: a scheme fixing; the result of the simulation.

4 24 Kirill Klimau and Sergey Medvedev / Procedia Engineering 136 ( 2016 ) It received experimental confirmation when using modern the interferometrical of technologies of the analysis of the stress-deformed states (SDS) of various objects [5]. On the classical chart of distribution of stresses at the cross section of a butt seam there is a stretched zone of a seam and the squeezed vicinities; where the stretching stress reaches a fluidity limit. The similar picture of distribution of the stretching and squeezing stresses is formed by the method stated by authors in work of [3] (Fig. 2). So there is a possibility of expeditious formation of the SDS for designs with a large number of the short welded seams placed in space arbitrarily. In Fig. 3a it is shown how the technique proves welding on a plate end face. The bend of a plate is formed at the expense of zones of comprehensive clamping in a welding zone. In laboratory of arc welding of the Minsk tractor plant experimental confirmation of observed residual deformations with use of special installation and the robotized welding process is received (Fig. 3. Coincidence of results of experiment with welding on a plate and computing calculations, allow to draw a conclusion that not the fictitious shrinkable force (V.A. Vinokurov) leads to these results, but pressed out from all directions the volume of the cooling-down metal (N.O. Okerblom). We assume that linear fictitious shrinkable force doesn't reflect difficult the SDS of a welded construction. In a construction of a frame of the dump truck the BelAZ with a loading capacity of 130 tons and more, is some kilometers of different short welded seams. Big total length of seams on a body of the modern bus, tram or trolleybus too. But the majority of computer calculations of these objects is limited to the static analysis without taking note of welded seams on movements of all welded design, and also increase of stress in these areas. In work [6] the program module forming on three-dimensional model of a zone of alloyage and a zone of irreversible plastic deformations is offered. According to information on these objects the perhaps following: creation of finite element models; their loading by stress close to a yield stress of the main metal; performance of static and dynamic calculations, with fixing of a place and time of formation of the centers of destruction and display of this process. There is an opportunity to compare behavior of a uniform isotropic construction (analog of a moulded construction) and a welded construction to the changed mechanical properties of a seam and the main metal, to the changed internal SDS of all construction, its rigidity. Interaction of this SDS with external loading, its reflection in the corresponding computing calculations, provides to the engineer-welder additional information for increase of working capacity and a resource of this welded construction. This approach of loading of zones of welded seams stress equivalent to a yield stress of the main metal, demands enough big computing resources. Similar resources the Republican supercomputer center of collective use placed at the UIIP NAN of Belarus has. The National grid-network unites supercomputer resources of other organizations of Republic of Belarus. There is an opportunity for experts to use license versions of ANSYS, LS-DYNA and ADAMS systems in the mode of remote access. Also work on use of systems of the finite element analysis in open codes for calculation of welded constructions is carried out. In Fig. 4a the construction of the hook-on device with a spherical heel for a tractor is shown. The device is worked at short-term shock loadings, character and which values are known. Static calculation guaranteed working capacity at the set loading. But in the conditions of the accelerated tests at the special hydraulic stand the device failed, having cracked at some distance with welded seams. By the offered program technique of supercomputer modeling in-depth study of the mentioned construction is conducted, the factors leading to destruction are shown (Fig. 4. It should be noted that in ideal computing model destruction at several cycles of loading happens only on the main metal. The experts who copied foreign analog are rather guilty.

5 Kirill Klimau and Sergey Medvedev / Procedia Engineering 136 ( 2016 ) Fig. 4. Results of virtual tests of the hook-on device: the analysis model without welded seam and with it; the result of the simulation without welded seam and with it. The welded case of the protected wheel vehicle from work [8], Fig. 5 can be one more example of use of expected supercomputer modeling of difficult welded constructions. Are indicative changes of global rigidity of a construction after welding, and also change of its reaction to influence of a blast wave. Also there is a change of nature of destruction and the corresponding deformation and energy parameters. In the next plans: - use of expected supercomputer modeling for frameworks of buses of production of the Minsk automobile plant for the purpose of identification of the places reducing an operational resource; - welded designs of construction and road equipment of JSC AMKODOR and other Belarusian enterprises. In educational process on "Powder Metallurgy, Welding and Technology of Materials" chair of the Belarusian national technical university authors use license software and technologies of supercomputer modeling. Authors invite to mutually beneficial cooperation on expected supercomputer modeling of welded constructions the interested organizations and certain experts. It is represented that only in similar collaboration perhaps successful overcoming of problems at design and modeling of welded constructions.

6 26 Kirill Klimau and Sergey Medvedev / Procedia Engineering 136 (2016) Fig. 5. Difference in behavior of an isotropic and welded construction at identical dynamic influence: the result of the simulation with welded seam; the result of the simulation without welded seam.

7 Kirill Klimau and Sergey Medvedev / Procedia Engineering 136 ( 2016 ) Conclusion In article methods of calculation of the SDS of a construction with welded seams are described, and results of the modelling with use of a finite elements method are also presented in the program of LS-DYNA. Need of use of supercomputers for the solution of such is shown. References [1] N.O. Okerblom, V.I. Demyancevich, I.P. Baikova, The design of the manufacturing technology of welded structures (Сomputational methods), Sudpromgiz, Leningrad, 1963, p [2] P. Zeng, Y. Gao, L.P. Lei, Welding process simulation under varying temperatures and constrains, Materials science & engineering A 499(1 2) (2009) Fifth International Conference on Physical and Numerical Simulations of Material Processing (ICPNS 2007), Zhengzhou, China, October 23 27, [3] S.V. Medvedev, Computer modeling of residual welding strains in technological design of welded structures, Welding production 8 (2001) [4] S.V. Medvedev, Computer modeling of residual welding strains in technological design of welded structures, Welding International 16(1) (2002) [5] I.A. Razumovskij, Interference-optical methods of solid mechanics. The MSTU. N. Uh.Bauman, Moscow, 2007, p [6] D.P. Kunkevich, S.V. Medvedev, M.V. Petrushina, J.G. Yakovleva, The program complex of modeling of welded joints for the prediction of total residual deformations of steel structures, Mathematical modelling and information technologies in welding and related processes, Kiev, IES them. E. O. Paton of NAS of Ukraine, 2008, p. 36. [7] D.P. Kunkevich, S.V. Medvedev, Constructive-technological designing of welded structures of road equipment in the environment of supercomputer SKIF, Information technology of the Union state program Triada. Main results and perspectives, UIIP NAS of Belarus, Minsk, 2010, pp [8] S.V. Medvedev, K.A. Klimau, V.S. Grinuk, Computer simulation of the effects of on the body of a universal armoured vehicle and its crew by means of LS-DYNA, VIII international scientific and technical conference Information technologies in industry, UIIP NAS of Belarus, Minsk, 2015, pp