The development of the notions of deformation and strength properties of potato tubers flesh

Abstract

On the basis of publications in recent years, ideas about the deformation and strength properties of the flesh of potato tubers are being developed. The study is based on the analysis of experimental data on compression tests of cylindrical specimens cut from the flesh of potato tubers. The experiments were carried out taking into account the relaxation properties of the flesh. The diagrams of destruction of cylindrical samples by uniaxial compression revealed a number of features that made it possible to form an idea of the deformation-strength properties of potato pulp, taking into account the degree of its lethargy. Additional information is provided by experiments with intermediate unloadings, which start with ?> 0.1 MPa. A comparison of their graphs with the initial part of the diagram shows the absence of inelastic deformations within the limits of stresses in the samples from zero to values close to 0.1 MPa. Stresses ?> 0.1 MPa lead to the formation of inelastic deformations in the samples, which makes it necessary in the Hooke formula to abandon the use of the concept of a Young's modulus, which describes only elastic deformation. Instead of the Young's modulus, it was proposed to introduce a more general concept of the modulus of rigidity. Based on the analysis of the previously developed criteria for the rigidity of tubers of various flaccidity, two main ones were selected, which is associated with the simplicity of obtaining data for their calculation and sensitivity to changes in the flaccidity of tubers.