V.G. Zhukov1, N.R. Andreev2, D.V. Bezrukov1
1Moscow State University of Food Productions, Volokolamskoe shosse, 11a, Moskva, 125080, Russian Federation
2All-Russian Research Institute of Starch Products, ul. Nekrasova, 11, pos. Kraskovo, Moskovskaya obl., 140051, Russian Federation
Summary. Under production conditions, potato grinders have powerful electric drives with large energy consumptions. Calculation of cutting energy and other values of grinding is based on the results of direct tests, therefore physical and mechanical indices of potato tubers material are used in design formulas as the parameters non-obviously uniting and taking into account the complex of values forming their meaning. At the same time, mechanical characteristics of potato remain not revealed. The work is aimed at determining the nature of deformation and strength mechanical characteristics at compression of potato tubers samples. GOST 25.503-97 “Calculations and strength tests. Methods of mechanical tests of metals. A testing method of compression strength” was the basis for establishing sample sizes. The graph of a potato sample deformation is close to a parabolic curve with the top in the origin of coordinates; its bulge is directed to the abscissa axis (the axis of deformations), and from some value of pressure load it becomes almost linear on the most part up to destruction. By these two features, it differs in principle from classical test graphs of metals. The main part of the curve can be described by the equation σ = a +Eε. The sample cut out from a potato tuber collapses at the effort about 0.5 MPa according to the type of fragile material by splitting on the plane inclined at an angle of 45 degrees to an axis in the direction of action of the maximal tangential stresses. The relaxation by way of a decrease in the load on the sample by the time of its destruction was 10-12 %.
Keywords: potato tuber, starch, samples, compression tests, graph of destruction by compression, breaking point, relaxation.
Author Details: V.G. Zhukov, D. Sc. (Techn.), prof. (е-mail: z-v-gr@ mail.ru); N.R. Andreyev, D. Sc. (Techn.), corresponding member of the RAS, scientific supervisor (е-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.); D.V. Bezrukov, post graduate student.
For citation: Zhukov V.G., Andreyev N.R., Bezrukov D.V. Relaxation Effect at Testing Potato Samples by Compression. Dostizheniya nauki i tekhniki APK. 2016. V.30. No. 11. Pp. 121-122 (in Russ.).