Mechanik
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14.12.2018

Evaluation of possibilities of application of web-based tool for effective identification of mechanical properties of materials

Łukasz Wolski, Magdalena Kopernik

A main template of the web application GUI: 1 – a navigation bar, 2 – a view content and 3 – a dock menu

A main template of the web application GUI: 1 – a navigation bar, 2 – a view content and 3 – a dock menu

The main purpose of the work is to present and test the developed web-based tool to identify parameters of rheological equations, whose functionality according to the presented results is comparable to existing desktop applications. The developed web-based application with a user-friendly interface uses selected optimization methods (Powell and Hooke-Jeeves algorithms). Criteria for selecting optimization methods are: robustness and frequent application to identification problems described in literature. Testing the developed application consists of comparing the identified stress-strain curves obtained from mechanical tests using the developed tool and commercial desktop application, and performing efficiency tests for the analyzed examples of rheological equations and optimization methods. For this purpose, two material models were used: a simple Hollomon’s model and a multi-parameter model used for steel, in which the influence of softening during the dynamic recrystallization is insignificant. The presented software is implemented in technologies such as JDK 1.8, Spring Framework and PrimeFaces, and passes the efficiency tests successfully.

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The direct solid method of geometry analysis of the globoidal worm gear with the rotary teeth

Patrycja Ewa Jagiełowicz

Temporary tooth contact – the worm

Temporary tooth contact – the worm

The tooth contact analysis (TCA) in the wheel rotation function of the globoidal worm gear with rotary teeth was presented. To determine the contact in CAD system, the direct solid method of geometry analysis was used. In the gear the globoidal worm gear was used, and the classical worm wheel was replaced by the wheel with rotary teeth in the shape of the frustum of cone.

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Selected properties of ZrB₂ composites obtained by SPS method for parts of electro-erosion shaping machines

Annamaria Naughton-Duszova, Elżbieta Bączek, Marcin Podsiadło

Sintering furnance (a), graphite elements (b), ovenchamber (c)

Sintering furnance (a), graphite elements (b), ovenchamber (c)

The effect of the addition of silicon carbide and boron carbide powders on the properties of ZrB2 ceramic composites constituting UHTC materials (ultra high temperature ceramics) was investigated. Polycrystalline zirconium boride samples as well as matrix composites of this phase with addition of 2 and 10 wt.% SiC and B4C were obtained by pressure-assisted sintering using SPS/FAST (spark plasma sintering/field assisted sintering technique) in the temperature range of 1800÷2000°C. Samples were characterized by X-ray diffraction, scanning electron microscopy, hardness and fracture toughness. The obtained materials are characterized by a high relative density in the range of 97÷98%. Higher hardness and fracture toughness were observed for the composite obtained in temperature 1900°C.

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Triangulation methods for effusion holes measurements in combustion chambers of aircraft engines

Piotr Lampa, Mariusz Mrzygłód, Jacek Reiner

Experimental setup with triangulation head

Experimental setup with triangulation head

An important problem of modern aero-engines’ construction is effective cooling of combustor liner attained by effusion holes. The laser-drilled channels are a critical metrological challenge resulting from their small diameter (below 1 mm), irregular shape and angular orientation to the surface. Hence, in this case, the tactile CMM measurement methods are timeconsuming, error-susceptible and hazardous to the measuring stylus. The paper compares two methods of triangulation scanning of the surface of the engine combustion chamber with angular effusion holes (according to normal to surface and coaxially with hole). Additionally, four algorithms for processing measurement data were developed and evaluated, aiming at determination of the position and holes diameter. The paper also discusses the problem of measurement and calculation disturbance.

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