Study of the dynamic-mechanical and biomechanical properties of materials for daily use footwear insoles / Estudo das propriedades mecânico-dinâmicas e biomecânicas de materiais para sobrepalmilha de calçados de uso diário

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The present study had the objective of evaluating the following materials: flexible poliuretane foam, lattice synthetic SBR rubber foam and expanded EVA used in the manufacturing of footwear daily use insoles, using as independent variables the density properties and thickness to detect the influence in the mechanic-dynamic properties (dynamic deformation, energy absorption, impact resilience, mechanical histeresys by tension and restitution energy coefficient) and as dependent the biomechanics (pressure peak to plant). The instruments were: machine for the deformation by dynamic compression, dinamometer of measuring compression force stress/strain to determine the energy absorption, pendulum resiliometer Schob, machine of mechanical rehearsal to determine the energy restitution coefficient, Pedar X System of Novell GMBH for determining the distribution of the plant pressure. The adopted procedures were: a) research structured with designers, footwear technicians and insole manufacturers to determine the most employed thicknesses and densities; b) to collect the material with the insole manufacturers; c) to characterize the materials through density rehearsals, hardness Asker C, thickness, thermal transitions and analysis of the cellular structure through scattering electronical microscopy; d) to determine the properties of the dependent variables. To verify the consistence of the methodology, a pilot test was applied. The tests used to evaluate the obtained results were: parametric and not parametric tests, normality test Shapiro-Wilk. For the statistical evaluations of the software was used SPSS and Excel. After all that the equipments to evaluate the dynamic deformation, absorption of energy and impact resilience to the are not appropriate to the proposed methodology and for the restitution coefficient energy should be reduced the impact mass or to cut off piezoelectrical tip height. On the point of view of the material, it was found out that the thickness affect the pressure pick for expanded EVA, and the thickness will have larger or smaller impact as it reduces the apparent density of the expanded EVA. However, for the lattice of SBR foam, very away cannot determine correlation between apparent density and pressure peak, it can be said that the apparent density affects the pressure peak, as well as for the PU foam. A interrelation among pressure to peak plant and the restitution coefficient of energy, it should not be absolute because it had to control the intervenient variables better. However, in a general way, it can be said that as larger the coefficient of larger restitution of energy is, the higher the pressure peak is. Concerning comfort, the thickness of 2 mm is inadequate, mainly when in cellular materials of the type it skims with apparent density in the strip of 0.20 or expanded materials with density in the strip above 0.30 and with thickness above 5 mm.

ASSUNTO(S)

mecânico-dinâmicas insole palmilha pico de pressão mechanical-dynamic educacao fisica pressure peak

ACESSO AO ARTIGO

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