Wyniki wyszukiwania - BazTech

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Investigation of the draft-and-power, and agreotechnical indicators of the work of a ploughing aggregate, created according to the scheme «push-pull»

Nadykto V., Ivanov S., Kistechok O.

Journal of Research and Applications in Agricultural Engineering

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2017

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Vol. 62, nr 1

136--139

EN

The article expounds the research results of two ploughing machine and tractor aggregates (МТА). One of them consisted of a tractor HTZ-16131, a front-mounted double-furrow and a rear-mounted four furrow ploughs (the scheme «push-pull» «2+4»), but the other - of the same tractor and a five furrow rear-mounted plough (the scheme «0+5»). The obtained experimental data indicate that the working width of the aggregate assembled according to the scheme «2+4» was by 20.9% greater than that of the aggregate created according to the scheme «0+5». Although the operating velocity of travel of the first MTA turned out to be by 1.5% lower, its efficiency, due to a greater working width, was by 19.5% higher. Therefore the specific fuel consumption by the aggregate created according to the scheme «2+4» turned out to be by 11.5% lower. The mean root square deviation in the depth of ploughing by both the compared aggregates did not exceed the agrotechnical requirements (± 2 cm); however the use of a ploughing aggregate, created according to the scheme «push-pull» «2+4», en-sures soil cultivation with more uniform plough travel by depth.

PL

Artykuł prezentuje wyniki badań agregatów ciągnikowych z dwoma maszynami uprawowymi (МТА). Jeden z nich zawierał ciągnik HTZ-16131, pług dwuskibowy zawieszony z przodu oraz pług czteroskibowy zawieszony z tyłu ciągnika (schemat «push-pull» «2+4»), a drugi - ten sam ciągnik i pług pięcioskibowy zawieszony z tyłu ciągnika (schemat «0+5»). Otrzymane wyniki badań eksperymentalnych wskazują, że szerokość robocza agregatu utworzonego według schematu «2+4» była o 20,9% większa niż agregatu utworzonego według schematu «0+5». Chociaż prędkość robocza pierwszego agregatu (MTA) okazała się o 1,5% mniejsza, jego wydajność, z powodu większej szerokości roboczej, była o 19,5% większa. Dlatego jednostkowe zużycie paliwa przez agregat utworzony według schematu «2+4» okazało się o 11,5% mniejsze. Odchylenie kwadratowe głębokości orki w obydwu porównywanych agregatach nie przekroczyło wymagań agrotechnicznych (± 2 cm); jednakże użycie agregatu uprawowego, utworzonego według schematu «push-pull» «2+4», zapewnia uprawę gleby z bardziej niezmienną głębokością orki.

2

Low cycle fatigue of steel in strain controled cyclic bending

Kulesa A., Kurek A., Łagoda T., Achtelik A., Kluger K.

Acta Mechanica et Automatica

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2016

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Vol. 10, no. 1

62--65

EN

The paper presents a comparison of the fatigue life curves based on test of 15Mo3 steel under cyclic, pendulum bending and tension-compression. These studies were analyzed in terms of a large and small number of cycles where strain amplitude is dependent on the fatigue life. It has been shown that commonly used Manson-Coffin-Basquin model cannot be used for tests under cyclic bending due to the impossibility of separating elastic and plastic strains. For this purpose, some well-known models of Langer and Kandil and one new model of authors, where strain amplitude is dependent on the number of cycles, were proposed. Comparing the results of bending with tension-compression it was shown that for smaller strain amplitudes the fatigue life for both test methods were similar, for higher strain amplitudes fatigue life for bending tests was greater than for tension-compression.

3

Push-pull resonant DC-DC isolated converter

Jalbrzykowski S., Citko T.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2013

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Vol. 61, nr 4

763--769

EN

A new concept of a DC-DC converter with galvanic isolation is proposed in this paper. The converter belongs to the class E resonant converters controlled by pulse width modulation via frequency regulation (PWM FM). Due to the possibility of operation in the boost and buck modes, the converter is characterized by a high range of voltage gain regulation. The principle of converter operation described by mathematical equations is presented. The theoretical investigations are confirmed by p-spice model simulations and the measurement of an experimental model of 1kW laboratory prototype.

4

Influence of loading type on the shape of fatigue lifetime curve

Bokuvka O., Novy F., Mintach R., Cincala M.

International Journal of Applied Mechanics and Engineering

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2010

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Vol. 15, no 2

321-328

EN

The paper is devoted to an experimental examination of the influence of loading type on the shape of fatigue lifetime curve of the high-carbon-chromium bearing steel (100Cr6). The push-pull and rotating bending loading tests (R=-1) were used with the aim to obtain experimental data in the region from [...] cycles to [...] cycles. The shape of fatigue lifetime curve of 100Cr6 bearing steel depends on the loading type. The S-N curve obtained using rotating bending consists of two parts corresponding to surface and subsurface fatigue crack initiation, resulting in a stepwise S-N curve. In this case, the typical stepwise S-N relationship clearly indicates that the mechanism of fatigue crack initiation transfers from the surface to subsurface with decreasing the applied stress level. On the other hand, the S-N curves obtained at push-pull loading revealed a continuous downward slope without any indication for a plateau region and subsurface fatigue crack initiation occurs in the whole range of amplitudes. This fact has to be taken in consideration while selecting a structural material.

5

Monitoring pilot's eye movements during the combat flight - the white box

Ober J. K., Ober J. J., Malawski M., Skibniewski W., Przedpelska-Ober E., Hryniewiecki J.

Biocybernetics and Biomedical Engineering

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2002

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Vol. 22, no. 2-3

241-264

EN

Modern fighter pilots are often exposed to excessive accelerations. The resulting brain hipoxia can lead to G-LOC (G-induced loss of consciousness). Authors discuses the effects of microcirculatory adaptation released by the push-pull condition (rapid change from minus to plus Gz). The memory effect of vaso-pull condition (rapid change from minus to plus Gz). The memory effect of vaso-constriction due to - Gz can be responsible for intermittent blocking of the compensatory vasodilatation and diminishing the +Gz tolerance of pilots tested on the centrifuge. Authors consider the push-pull condition to be analogous to the rapid blocking of the brain perfusion caused by the high plus Gz onset rates (1,G/s). Using the visual symptoms (narrowing of the visual field) is not longer adequate for monitoring the centrifuge push-pull trainig. Authors discuses the possibility of using the saccadic eye movements as being the most adequate physiological signal to monitor the pilot's consciousness. Measuring pilots eye movements requires to develop a miniature complex motion transducer which can be used during centrifuge training as well as during the flight (the White Box). Problems encountered during the system development are discussed.