Calculation of the stress-strain state of a cyclically loaded piston of a tractor diesel engine

Цилиндровые втулки относятся к наиболее нагруженным деталям судовых дизелей. Оценка их напряженно-деформированного состояния показывает, что последовательное форсирование дизелей по среднему эффективному давлению требует существенного пересмотра некоторых положений конструирования этих деталей. Это касается конструктивного оформления наружных поверхностей втулок, а также их закрепления в блоке цилиндров. В статье рассматривается влияние условий закрепления верхнего торца втулки и промежуточных опор-уплотнителей на деформирование цилиндровой втулки газовыми нагрузками. Показано, что для выбора оптимального места установки кольца-уплотнителя по длине втулки целесообразно исходить из минимизации воздействий на него со стороны подвижных газовых нагрузок. Предлагается расчётная методика, которая позволяет определить то место установки промежуточной опоры, где она практически не влияет на параметры напряженно-деформированного состояния цилиндровой втулки судового дизеля с учётом особенностей закрепления её верхнего торца в цилиндровом блоке. Применение данной методики позволяет с учётом особенностей конкретного двигателя обоснованно решить вопрос размещения дополнительных опор-уплотнителей. Cylinder bushings are among the most loaded parts of marine diesel engines. Evaluation of their stress-strain state shows that the sequential forcing of diesel engines according to the average effective pressure requires a significant revision of some provisions for the design of these parts. This applies to the design of the outer surfaces of the bushings, as well as their fastening in the cylinder block. The article examines the influence of the conditions for fixing the upper end of the sleeve and intermediate support-seals on the deformation of the cylinder sleeve by gas loads. It is shown that in order to select the optimal place for installing the seal ring along the length of the sleeve, it is advisable to proceed from the minimization of the effects on it from the movable gas loads. A calculation method is proposed that allows you to determine the place of installation of the intermediate support, where it practically does not affect the parameters of the stress-strain state of the cylinder liner of a marine diesel engine, taking into account the peculiarities of fixing its upper end in the cylinder block. The use of this technique allows, taking into account the characteristics of a particular engine, to reasonably solve the issue of placing additional support-seals.

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RESEARCH OF INFLUENCE OF UNFINISHED CONSTRUCTION EXCAVATION ON STRESS-STRAIN STATE OF EXPLOITED BUILDING BEARING STRUCTURES

Building constructions. Theory and Practice ◽

10.32347/2522-4182.2.2018.3-12 ◽

2018 ◽

Vol 0 (2) ◽

pp. 3-12

Author(s):

A Banakh

Keyword(s):

Strain State ◽

Stress Strain ◽

Stress Strain State

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КОНСТРУКТИВНО-ТЕХНОЛОГІЧНІ ОСОБЛИВОСТІ ХВОСТО-ВИХ БАЛОК СІТЧАСТОГО ТИПУ З ПОЛІМЕРНИХ КОМПО-ЗИЦІЙНИХ МАТЕРІАЛІВ ВЕРТОЛЬОТІВ ТРАНСПОРТНОЇ КАТЕГОРІЇ

Open Information and Computer Integrated Technologies ◽

10.32620/oikit.2020.88.02 ◽

2020 ◽

pp. 15-30

Author(s):

А. Г. Гребеников ◽

И. В. Малков ◽

В. А. Урбанович ◽

Н. И. Москаленко ◽

Д. С. Колодийчик

Keyword(s):

Finite Element ◽

Strain State ◽

Layer Structure ◽

Metal Structure ◽

Element Model ◽

Stress Strain ◽

Element Analysis ◽

Mesh Structure ◽

Stress Strain State ◽

Mesh Structures

The analysis of the design and technological features of the tail boom (ТB) of a helicopter made of polymer composite materials (PCM) is carried out.Three structural and technological concepts are distinguished - semi-monocoque (reinforced metal structure), monocoque (three-layer structure) and mesh-type structure. The high weight and economic efficiency of mesh structures is shown, which allows them to be used in aerospace engineering. The physicomechanical characteristics of the network structures are estimated and their uniqueness is shown. The use of mesh structures can reduce the weight of the product by a factor of two or more.The stress-strain state (SSS) of the proposed tail boom design is determined. The analysis of methods for calculating the characteristics of the total SSS of conical mesh shells is carried out. The design of the tail boom is presented, the design diagram of the tail boom of the transport category rotorcraft is developed. A finite element model was created using the Siemens NX 7.5 system. The calculation of the stress-strain state (SSS) of the HC of the helicopter was carried out on the basis of the developed structural scheme using the Advanced Simulation module of the Siemens NX 7.5 system. The main zones of probable fatigue failure of tail booms are determined. Finite Element Analysis (FEA) provides a theoretical basis for design decisions.Shown is the effect of the type of technological process selected for the production of the tail boom on the strength of the HB structure. The stability of the characteristics of the PCM tail boom largely depends on the extent to which its design is suitable for the use of mechanized and automated production processes.A method for the manufacture of a helicopter tail boom from PCM by the automated winding method is proposed. A variant of computer modeling of the tail boom of a mesh structure made of PCM is shown.The automated winding technology can be recommended for implementation in the design of the composite tail boom of the Mi-2 and Mi-8 helicopters.

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