Contact Stress Area Measurement Of Spherical Fruit

This paper aims to measure the contact area of rubber spheres and oranges compressed against parallel rigid and flat plates. To measure this area a system composed of a transducer, an interface device and a microcomputer was used. The transducer is composed of a board on which some micro-switches were disposed in a linear and radial direction spaced 0.5 mm from each other. As the contact area was expanding, the micro-switches connected to the interface turned on, forming the bits that compose the binary word that measures the diameter of the area. The data acquisition system is in-charge of recording the measured area, as function of the deformation imposed to the spheres and to the orange fruit. The obtained area as a function of deformation was compared with the data reported by Linares, 1996.562195200Dal Fabro, I.M., (1979) Failure Theories for Apple Flesh, , E. Lansing, MI: Michigan State University. Ph.D. ThesisDeBaerdemaeker, J.G., (1975) Experimental and Numerical Techniques Related to the Stress Analysis of Apple Under Static Load, , E. Lansing, MI: Michigan State University. Ph.D. ThesisFerraz, A.C.O., (1987) Propriedades Mecânicas do Internódio Da Cana-de- açúcar: Uma Contribuição Metodológica, 98p. , Campinas: UNICAMP, 1987 Dissertação (Mestrado) - Faculdade de Engenharia Agrícola, Universiade Estadual de CampinasFinney, E.E., (1963) The Viscoelastic Behavior of the Potato, Solanum Tuberosum, Under Quasi-static Loading, , E. Lansing, MI: Michigan State University, 1963. Ph.D. Thesis - Agricultural Engineering Department, Michigan State UniversityHughes, H., Segerlind, L.J., A rapid mechanical method for determining Poisson's ratio in biological materials (1972) ASAE, Paper N. 71-310, , St. Joseph, MILaurenti, R., (1997) Influência Da Geometria dos Corpos de Prova Vegetais na Determinação de Propriedades Mecânicas, 140p. , Dissertação (Mestrado), Faculdade de Engenharia Agrícola, UNICAMP, Campinas, SPLinares, A.W., (1996) Estudo do Comportamento Viscoelástico de Frutos Esféricos, 134p. , Dissertação (Mestrado), Faculdade de Engenharia Agrícola, UNICAMP, Campinas, SPMase, G.E., (1970) Theory and Problems of Continuum Mechanics, 221p. , New York, McGraw-Hill il (Schaum's outline series)Monsenin, N.N., (1970) Physical Properties of Plant and Animal Materials, 1, 734p. , New York, Gordon and Breach Science PublishersRocha, J.V., Comportamento Mecânico de Minifardos de Feno de Soja Perene (Neonotonia Wightii Lackey C.v. Cianova), Submetidos a Ensaios de Relaxação Com Cargas Uniaxiais (1988) Campinas: UNICAMP, 104p. , 1988 Dissertação (Mestrado) - Faculdade de Engenharia Agrícola, Universiade Estadual de CampinasRosenfeld, D., Shmulevich, I., Rosenhouse, G., Three-dimensional simulation of the acoustic response of fruit for firmness sorting (1992) Trans. ASAE, 35 (4), pp. 1267-1274. , St. Joseph, MIShahabassi, Y., (1979) Experimental and Numerical Techniques Related to Maximum Allowable Depth of Apples in a Bulk Storage, , Unpublished Ph.D. Thesis. Michigan State University, East Lansing, Michigan, U.S.ASherif, S.M., Segerlind, L.J., Frame, T.S., An equation for the modulus of elasticity of radially compressed cylinder (1976) Trans. ASAETimoshenko, S.P., Goodier, J.N., (1970) Theory of Elasticity, , 3rd. Edition. McGraw-Hill Book Company, N.YVelez Pasos, C.A., (1987) Análise do Comportamento Mecânico de Laranjas À Granel Mediante Modelo de Elementos Finitos, 89p. , Campinas: UNICAMP, 1987 Dissertação (Mestrado) - Faculdade de Engenharia Agrícola, Universiade Estadual de CampinasYang, W.H., The contact problem for viscoelastic bodies (1966) Trans. ASME, pp. 395-401. , St. Joseph, M