scholarly journals Analysis by FEMof elasto-plastic deformation of beams with associated plate

2020 ◽  
Author(s):  
A.И. Притыкин
Keyword(s):  
Plastic Deformation ◽  
Strain Hardening ◽  
Load Capacity ◽  
Limit Load ◽  
Transverse Load ◽  
The Finite Element Method ◽  
Elastic Plastic ◽  
Hardening Modulus ◽  
Analytical Relations ◽  
Symmetric Profile

Для оценки несущей способности балок судовых конструкций надо определять их предельную нагрузку. Существующие расчетные зависимости, приводимые в справочных изданиях, далеко не всегда дают верные рекомендации, когда речь идет о балках с присоединенным пояском обшивки, который может намного превосходить размер свободного пояска. В работе проведен сравнительный анализ оценки предельной нагрузки, определяемой аналитически и путем упругопластического расчета методом конечных элементов с варьированием ширины присоединенного пояска. Рассматривался вариант упругопластического нагружения с линейным упрочнением. Полученные результаты показали, что приводимая в справочнике по СМК, зависимость для оценки предельной нагрузки балок с асимметричным профилем не совсем корректна из-за неполного включения присоединенного пояска в работу. Это дает завышенные значения предельной нагрузки. Проверены были также рекомендации по оценке прогибов балок в предельном состоянии, показавшие, что рекомендации справочника по СМК приводят к заниженным значениям прогибов. Для балок симметричного профиля расчетные зависимости справочника дают вполне удовлетворительные результаты. Отмечено, что если поперечная нагрузка вызывает текучесть стенки балки от сдвига, то влияние ширины присоединенного пояска практически не сказывается на ее несущей способности. Проанализировано также влияние величины секущего модуля на предельную нагрузку балки. For estimation of load capacity of the ship beams it is necessary to determine their limit load. Existing analytical relations, indicated in different manuals, not always give true recommendations when talk is about beams with associated plate many times exceeding dimensions of free flange. In this paper fulfilled comparative analysis of limit load, determined with analytical and elastic-plastic calculation by the finite element method. It was considered case of elastic-plastic deformation with lineal strain-hardening. Obtained results show that indicated in manual on the ship structural mechanics, relation for estimation of limit load of non-symmetric I-beams is not quite correct because of not complete inclusion of associated plate to the beam deformation. This lead to overestimation of limit loads. It was also shown that recommendations on evaluation of the deflections of beams in elastic-plastic deformations according to mentioned manual lead to much lower values of deflections. For beam with symmetric profile the relations of manual give quite satisfactory results. It was noticed, that if transverse load produces the yielding of web due to shear the influence of width of associated plate has no influence on the load capacity of beam. It was also analyzed influence of value of the strain-hardening modulus on limit load of beam.

An Approximate Model for an Elastic-Plastic Pipe Element Under Combined Loading

1975 ◽  
Vol 97 (1) ◽  
pp. 22-28 ◽  
Author(s):  
L. D. Larson ◽  
W. F. Stokey ◽  
W. E. Franzen
Keyword(s):  
Strain Hardening ◽  
Axial Load ◽  
Analytical Approach ◽  
Limit Load ◽  
Approximate Model ◽  
Experimental Results ◽  
Combined Loading ◽  
Elastic Plastic ◽  
Plastic Pipe ◽  
Plastic Analysis

An approximate model for the elastic-plastic analysis of a pipe element under combined loading is developed. The model is obtained by generalizing a limit load solution for combined pressure, bending, torsion and axial load to include strain hardening. For various combinations of loading of tubes, curvatures and twist angles are predicted and compared with experimental results and those predicted by a more rigorous analytical approach. The comparison shows that good results are obtained from the approximate model.

scholarly journals Load capacity of the board grillage with two stringers under ice loading

2021 ◽  
pp. 15-21
Author(s):  
А.И. Притыкин
Keyword(s):  
Load Capacity ◽  
Limit Load ◽  
Analytical Relation ◽  
Complex Character ◽  
Ice Load ◽  
Rectangular Area ◽  
Fixed Area ◽  
Numerical Coefficient ◽  
Analytical Relations

Снизить повреждаемость бортовых перекрытий при ледовых нагрузках можно за счет совершенствования расчетных зависимостей по оценке их несущей способности. Далеко не всегда такие зависимости, приводимые в справочных изданиях, дают верные рекомендации из-за не вполне ясного характера распределения нагрузок в сложных статически неопределимых системах. В справочнике по СМК приводится расчетная зависимость, позволяющая определить несущую способность регулярного перекрытия с двумя стрингерами при действиии локально распределенной нагрузки в пределах прямоугольника. Цель данной работы заключалась в оценке несущей способности реального бортового перекрытия ледокола типа Wind с помощью МКЭ при параметрах ледовой нагрузки, определяемой рекомендациями Морского Регистра РФ, и последующем сравнении полученных результатов с расчетами по теоретической зависимости, приведенной в справочнике. Полученные данные показали, что зависимость в справочнике для оценки несущей способности перекрытия дает удовлетворительно согласующиеся с МКЭ результаты после соответствующего уменьшения числового коэффициента в ней. При анализе несущей способности перекрытия варьировались шпация, толщина обшивки, высота стенок стрингеров и площадь приложения нагрузки. Установлено, что текучесть наблюдается в опорных сечениях шпангоутов и посредине их пролета, а из-за большой ширины присоединенного пояска обшивка у контура перекрытия практически никогда не течет. Полученные МКЭ результаты показали наличие обратно пропорциональной зависимости между предельной нагрузкой и шпацией при фиксированной площади нагружения. Отмечено, что увеличение толщины обшивки несущественно влияет на величину предельной нагрузки при остальных неизменных параметрах перекрытия. Выполненные расчеты позволяют кроме предельной нагрузки оценить также и величины прогибов при упругопластическом деформировании перекрытий, которые затруднительно подсчитать аналитически. To low damage of the board grillages under ice loading is possible by improving analytical relations on estimation of their load capacity. Not always such relations, bringing in manuals, give true recommendations because of complex character of the loads distribution in static indeterminate systems. Im manual on ship structural mechanics is giving analytical relation for determination of load capacity of regular grillage with two stringers under action of localy distributed load in rectangular area. Purpose of this study is to estimate load capacity of real board grillage of icebreaker of type Wind with help of FEM under parameters of ice load recommended in Maritime Register of RF, and following comparison of obtained results with calculation on analytical relation, given in manual. Obtained results show that relation in manual for estimation of load capacity of grillage give satisfactory results corresponding to FEM only after corresponding reducing of numerical coefficient in it. Under analysis of load capacity of grillage, it was changing frame space, thickness of plating, depth of stringers and area of application of load. It was estimated that most loaded zones of frames are their sections near supports and in the mid-span. Because of big width of associated plate the plating near contour of grillage is never yielding practically. Results obtained by FEM show existence of inversely proportional relation between the limit load and space framing under fixed area of loading. It was noticed that increasing of the plating thickness influent not essentially on value of the limit load under all other parameters of grillage unchangeable. Performed calculations allow to estimate limit load and value of deflections under elasto-plastic deformation of grillage, which is difficult to calculate analytically,

Contact Behaviors of Coated Asperity with Power-Law Hardening Elastic–Plastic Substrate During Loading and Unloading Process

2018 ◽  
Vol 10 (03) ◽  
pp. 1850034 ◽  
Author(s):  
Xiqun Lu ◽  
Fuzhan Huang ◽  
Bin Zhao ◽  
Leon M. Keer
Keyword(s):  
Finite Element Method ◽  
Plastic Deformation ◽  
Finite Element ◽  
Power Law ◽  
Coating Thickness ◽  
Rapid Decrease ◽  
Plastic Substrate ◽  
The Finite Element Method ◽  
Elastic Plastic ◽  
Loading And Unloading

The behavior of a coated asperity contacting with a rigid flat during the loading and unloading processes is investigated using the finite element method. The power-law hardening elastic–plastic substrate is considered, and the effect of the substrate hardening exponent and the coating thickness on the contact behavior is studied. It is shown that in the loading process, the contact load increases more slow and the contact area increases faster as the interference increases for smaller coating thickness and hardening exponent cases, and the coating thickness recovers more obviously after a rapid decrease. In the unloading process, the residual interference and the pileup effect of the asperity surface is larger for smaller coating thicknesses and hardening exponents, and the energy loss due to the plastic deformation is larger accordingly.

scholarly journals The Solution of the Thermal Elastic-Plastic Problem of Turbine Disk by the Incremental Finite Element Method

1985 ◽  
Author(s):  
Sun Jin-Wen ◽  
Ouyang Chang ◽  
Fang Jing-Yan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Load Capacity ◽  
Limit Load ◽  
Turbine Disk ◽  
Fracture Characteristics ◽  
Elastic Plastic ◽  
Loading And Unloading ◽  
Plastic Stage ◽  
Element Method

In this paper, a stress analysis method and a computation program of the solution for the thermal elastic-plastic problem of turbine disk in an aeroengine are presented by incremental finite element method. That method (It is suitable to the axisymmetric disk in the gasturbine, compressor, steam turbine as well) may be used to compute the stress and displacement of turbine disk at its thermal elastic or thermal elastic-plastic stage, its cracking revolving speed and limit load capacity and what part of that enters into the plastic zone first. The method may be used to compute its loading and unloading process, its residual stress and displacement as well. It is important to analyse the strength of the turbine disk and its fracture characteristics.

scholarly journals Influence of Different Strain Hardening Models on the Behavior of Materials in the Elastic–Plastic Regime under Cyclic Loading

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5323
Author(s):  
Peter Sivák ◽  
Peter Frankovský ◽  
Ingrid Delyová ◽  
Jozef Bocko ◽  
Ján Kostka ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Strain Hardening ◽  
Compliant Mechanisms ◽  
Linear Collider ◽  
Cyclic Stress ◽  
Practical Applications ◽  
Elastic Plastic ◽  
Plastic Regime ◽  
Initial Area ◽  
Elastic And Plastic Deformation

In exact analyses of bodies in the elastic–plastic regime, the behavior of the material above critical stress values plays a key role. In addition, under cyclic stress, important phenomena to be taken into account are the various types of hardening and the design of the material or structure. In this process, it is important to define several groups of characteristics. These include, for instance, the initial area of plasticity or load which defines the interface between elastic and plastic deformation area. The characteristics also include the relevant law of plastic deformation which specifies the velocity direction of plastic deformation during plastic deformation. In the hardening condition, it is also important to determine the position, size and shape of the subsequent loading area. The elasto-plastic theory was used for the analysis of special compliant mechanisms that are applied for positioning of extremely precise members of the Compact Linear Collider (CLIC), e.g., cryomagnets, laser equipment, etc. Different types of deformation hardening were used to simulate the behavior of particular structural elements in the elastic–plastic regime. Obtained values of stresses and deformations may be used in further practical applications or as default values in other strain hardening model simulations.

Friction Force and Stresses Analysis for Contact of Assembled Details

2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Plastic Deformation ◽  
Friction Force ◽  
Sliding Friction ◽  
Friction Model ◽  
Contact Interface ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

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