Research on the Compressive Forming Characteristics of Rice Husk (No. 2)

Abstract

In order to clear the behavior of compression stress and strain characteristic of rice husk, the stress relaxation test and the creep test were experimented using the plunger and cylinder type compression device. Some results are summarized as follows.
1) The relaxation modulus of rice husk had a linearity and the following equation was obtained in relation between the relaxation modulus and the time,
G(t)=a·logt+b
where, G(t) is the relaxation modulus, t is the time and a, b are constant values.
2) The larger the initial stress, the larger the value of relaxation spectrum and the shorter the relaxation time.
3) The creep compliance of rice husk had a linearity and the following equation was obtained in relation between the creep compliance and the time,
J(t)=c·logt+d
where, J(t) is the creep compliance, t is the time and c, d are constant values.
4) The smaller the initial compression stress, the larger the ratio of the increase of the compression stress and the value of retardation spectrum.
5) The creep strain and the residual strain had a tendency to increase with the increase of the number of repeated creep tests.
6) The result of the stress relaxation test and the result of the creep test were compared using the approximate equation. From this comparison, it may he conclude that these two results could convert together.