В данной работе показано, что при оценке и обеспечении живучести сварныхметаллоконструкций важную роль играют технологические факторы. Учет их влияния реализуется на основе применения метода конечных элементов. Описана численная методика расчета остаточных сварочных напряжений и деформаций в элементах сварных металлоконструкций.Численнообосновантехнологическийметодповышенияживучестиуказанногоклассаметаллоконструкций

Behrendt, F.F.

Gunther, R.W.

Jost, G.

Keil, S.

Mahnken, A.H.

Mottaghy, F.M.

Pietsch, H.

Florian F Behrendt

Hubertus Pietsch

Gregor Jost

Sebastian Keil

Felix M Mottaghy

Rolf W Günther

Andreas H Mahnken

Crossref

Journal of Medical Imaging and Radiation Oncology

Low-osmolar monomeric versus iso-osmolar dimeric contrast media: An intra-individual comparison in CT angiography using an animal model

Danenova, G. T.

Akhmetzhanov, T. B.

Electronic archive of Tomsk Polytechnic University

XIV МЕЖДУНАРОДНАЯ КОНФЕРЕНЦИЯ СТУДЕНТОВ, АСПИРАНТОВ И МОЛОДЫХ УЧЕНЫХ «ПЕРСПЕКТИВЫ РАЗВИТИЯ ФУНДАМЕНТАЛЬНЫХ НАУК» 8  Россия, Томск, 25-28 апреля 2017 г. Том 3. Математика                             COMPUTER MODELING OF THE STRESS-STRAINSTATE OF WELDED CONSTRUCTION  G.T. Danenova, T.B. Akhmetzhanov Scientific Supervisor: Prof., Dr. M.R. Nurguzhin KaragandaStateTechnicalUniversity Kazakhstan, Karaganda, B.Mira., 56, 100027 E-mail: g.danenova@kstu.kz  КОМПЬЮТЕРНОЕ МОДЕЛИРОВАНИЕ  НАПРЯЖЕННО-ДЕФОРМИРОВАННОГО СОСТОЯНИЯ СВАРНЫХ КОНСТРУКЦИЙ Г.Т. Даненова, Т.Б. Ахметжанов,  Научный руководитель: профессор, д.т.н. М.Р.Нургужин Карагандинский государственный технический университет Казахстан, Караганда, б. Мира, 56, 100027 E-mail: g.danenova@kstu.kz  Аннотация. В данной работе показано, что при оценке и обеспечении живучести сварных металлоконструкций важную роль играют технологические факторы. Учет их влияния реализуется на основе применения метода конечных элементов. Описана численная методика расчета остаточных сварочных напряжений и деформаций в элементах сварных металлоконструкций. Численнообосновантехнологическийметодповышенияживучестиуказанногоклассаметаллоконструкций.  Introduction.At the present time the maintenance of the welded construction serviceability over normative service life is provided by the maintenance system on the basis of the guiding documents according to the concept of “safe damage”. However, experience has shown [1, 2] the following: 1. There is no uniform methodological approach to the development of methodical directive. The approach should provide reliability and completeness of conclusions to make an evaluation of residual resource. 2. Numerical values of critical parameters of the defects (that are contained in the guiding documents) are not proved and considerably underestimated in many cases. 3. The criterion of a marginal state is not evident for a product as a whole (not for a separate element, a detail or unit) when estimating a residual resource. 4. Only total data about the buildup of welded design are fixed in the maintaining organizations. There are no data on loadings in various time intervals. 5. Technological factors relating to welding (high residual stresses and great plastic strains) are not considered in the guiding documents. Materials and methods.The structure of welded metal construction (WMC) survivability estimation has been taken into account the above mentionedfactors. The base concepts of safe operation of WMC are given there. It is necessary to note that the estimation of survivability includes the whole complex of tasks: the estimation of the current object condition; prediction of developing this condition for the near future; recommendations about XIV МЕЖДУНАРОДНАЯ КОНФЕРЕНЦИЯ СТУДЕНТОВ, АСПИРАНТОВ И МОЛОДЫХ УЧЕНЫХ «ПЕРСПЕКТИВЫ РАЗВИТИЯ ФУНДАМЕНТАЛЬНЫХ НАУК» 9  Россия, Томск, 25-28 апреля 2017 г. Том 3. Математика                             optimum period of operation before getting out this object or before its next repair. In this connection it is very important to choose a correct method of calculating the crack resistance parameters of WMC subject to the technology factors related to welding. Such approach demands the defining residual stresses and strains at the first stage of the problem solving. The complex of investigations of forming residual stresses and strains was realized on the basis of the above mentioned approach. Joints as the short seam executed on a plate of 100х200х6 mm are considered. The scheme of flat tension is accepted. Power of the welding source is q = 12600 W, the speed is V= 0,01 m/s.  The thermo-physical constants correspond to the data of the St3 steel. The problem was solved by using the program ANSYS. Results.Some results are shown in figures 1-3.  According to the result it is established that forming volumetric residual stretching stresses in zones of the ends of short welds and in places of their crossing is connected to the value of specific energy input rates of weldingδnq . It is shown that 2/5,12 mmWqn ≥δ  at defining the stress –strain state (SSS) of plates with short welding can be calculated approximately by the pattern of plane stress condition.  0 40 80 120 160 200   0 -1 -2 -3   1  y=0  y=0  x, mm ε , % 0 40 80 120 160 200 123405 y=5mm  y=0  y=3mm  x, mm ε , %  5  4  3  2  1  4  2  3  1  Fig. 1. The diagrams of residual strains in the plate 100x200x6mm 1 - experimental data ; 2 - calculation data by the FEM;  3 - calculation data by the FDM; 4 - calculation data by ANSYS program; 5 - calculation data by the FEM KELAPS  The feature of the approach is the account of redistributing residual stresses during the crack growth. It is established that the factor of residual stresses intensity can be estimated approximately by Wells formula within the limits of a weld (jcr ll ≤ ). XIV МЕЖДУНАРОДНАЯ КОНФЕРЕНЦИЯ СТУДЕНТОВ, АСПИРАНТОВ И МОЛОДЫХ УЧЕНЫХ «ПЕРСПЕКТИВЫ РАЗВИТИЯ ФУНДАМЕНТАЛЬНЫХ НАУК» 10  Россия, Томск, 25-28 апреля 2017 г. Том 3. Математика                             a) b)  Fig.2. Stress state of plate: a – stresses xσ ;  b - stresses yσ   Fig.3. The residual strains yε  Conclusion.The calculation of the stress-strain state of units and joint of welded metal constructions also allows applying seriously the methods of regulation and elimination of residual stresses and strains, developing the constructive - technological procedures aimed at formatting more favorable residual stress fields in WMC. It’s shown that it’s impossible to completely eliminate the manifestation of residual stresses and strains. But it’s possible to reduce significantly their negative influence on the loading capacity of welded metal constructions by controlling them during designing, manufacturing and operating.  REFERENCES 1. Ryakhin, V.A., Moshkarev, G.N. (1984).  Service life and stability of welded structures of construction site and road making machines. Moscow: Mashinostroenie [in Russian]. 2. Paul Colegrove, Chukwugozie Ikeagu, Adam Thistlethwaite, Stewart Williams, Tamas Nagy, WojciechSuder, Axel Steuwer, ThiloPirling. (2009). The welding process impact on residual stress and distortion. Science and Technology of Welding and Joining, 14(8), 717-725. 3. Schaumann P., Collmann M. (2013).  Influence of weld defects on the fatigue resistance of thick steel plates. Procedia engineering, 66, 62- 72. 

Компьютерное моделирование напряженно-деформированного состояния сварных конструкций

Behrendt, Florian F.

Pietsch, Hubertus

Jost, Gregor

Keil, Sebastian

Mottaghy, Felix

Günther, Rolf W.

Mahnken, Andreas H.

Publikationsserver der RWTH Aachen University

Low-osmolar monomeric versus iso-osmolar dimeric contrast media: an intra-individual comparison in CT angiography using an animal model

Mottaghy, Felix Manuel

RWTH Publications

INTRODUCTION: The aim of this study was to compare intra-individual contrast enhancement in multidetector-row computed tomography using the low-osmolar monomeric iopromide 300 and the iso-osmolar dimeric iodixanol 320. METHODS: Repeated computed tomography scanning of the chest of five pigs was performed under standardised conditions using iopromide 300 (300 mg I/mL) and iodixanol 320 (320 mg I/mL) with an identical iodine delivery rate of 1.5 g I/sec and a total iodine dose of 300 mg/kg body weight. Time-enhancement curves were computed, and pulmonary and aortic peak enhancement, time-to-peak and plateau time above 300 Hounsfield units (HU) were analysed. RESULTS: Intra-individual comparison revealed no statistically significant differences in contrast enhancement between the iopromide 300 and iodixanol 320 in the pulmonary artery and the aorta (620 vs 552 HU; P = 0.13). There was no significant difference between the two CM in the plateau time at the pulmonary artery and the aorta (P = 0.75 and P = 0.24, respectively). Aortic peak time was significantly earlier with iopromide 300 than with iodixanol 320 (P = 0.004). CONCLUSIONS: Low-osmolar monomeric and iso-osmolar dimeric CM provide a similar and suitable vascular contrast enhancement

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Maastricht University Research Portal

Компьютерное моделирование напряженно-деформированного состояния сварных конструкций

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Electronic archive of Tomsk Polytechnic University

Publikationsserver der RWTH Aachen University

RWTH Publications

NARCIS

Maastricht University Research Portal

Maastricht University Research Portal