No cálculo de estruturas de silos vem-se utilizando, ao longo dos tempos, novas ferramentas e métodos visando à determinação das características dos produtos armazenáveis. Objetivou-se, com a pesquisa, determinar as propriedades mecânicas e de fluxo de produtos granulares como grãos de arroz e milho triturado, com teores de umidade de 10, 12 e 14% e de farinha de mandioca, produto este considerado pulverulento com teores de umidade de 10 e 12%. Para a determinação das propriedades mecânicas foram realizados ensaios de compressão em célula especialmente confeccionada para esta finalidade. Foram utilizadas quatro cargas de compressão (5, 10, 15 e 20 kN). Os ensaios de propriedades de fluxo foram realizados utilizando-se equipamento de cisalhamento translacional conjugado com célula de cisalhamento denominada Jenike Shear Cell. Todos os ensaios foram realizados no período de julho a setembro do ano de 2012. Pode-se afirmar que os resultados satisfizeram o preconizado pela metodologia de tipo de fluxo e as adotadas pelas normas internacionais; os valores médios das propriedades mecânicas foram consistentes aos encontrados na literatura.

For the calculation of silos structures it has been used new methods and computational tools that require mechanical properties knowledge that are still unknown for most storable materials, especially grains. In this context, we aimed to determine the mechanical properties of rice and beans grains with moisture contents of 10, 12, and 14% by applying four compressive loads (5, 10, 15 and 20). The determined mechanical properties were Poisson's ratio (ν), Modulus of Elasticity (E), and the dilatancy angle (ψ). The procedure consisted in the application of the load in compression cell, adapted from MOLENDA & STASIAK, aiming to simulate loading and unloading of silos. We observed that the Poisson's ratio calculated for both loading and unloading, presented higher values than the experimental values, with the increase of their moisture content; the experimental elastic modulus presented higher values than the calculated ones, and both increased their values with the increase of their moisture content; the dilatancy angle decreased with the increase of moisture content and compressive loads.

For design of vertical silos walls involving the storage of bulk solids to be safe and reliable, it is important knowing the largest possible number of variables such as: flow properties, silo geometry and pattern of flow desired. In order to validate the theories of flow prediction and design of conical hoppers, the flow properties of two bulk solids were determined, the theories of Jenike's flowability and Enstad and Walker for hopper design were analyzed and the results were compared with those experimentally obtained in a reduced model of a semicircular-section silo. Results show that Enstad theory for the hopper design is adequate to occur mass flow inside the silo, and for the sizing of the discharge outlet, the Walker's theory was closer to the appropriate than Jenike's theory, which was higher around 100% than the experimental hopper outlet.

xxxx