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There are two reasons for measuring the mechanical properties of cereal grains. First, the possibility of grain classification based on texture and, second, to obtain information for modification in the design of post-harvest machinery. In both cases, the objectives will be the reduction of qualitative and/or quantitative losses of grain. In this research, eight different parameters obtainable from the force-deformation curves of wheat kernels un-der compression were determined. The most important of these included: the apparent modulus of elasticity, maximum compressive contact stress and maximum load at rup-ture. Other grain characteristics such as the dimensions of single wheat kernels and the particle size index of bulk samples for five varieties of wheat were measured. By per-forming 200 uniaxial compression tests on intact wheat kernels (from soft to very hard varieties), the values of modulus of elasticity ranging from 486 to 1631 MPa were deter-mined based on measurements according to the Hertz theory. Results indicated a simple linear relationship between grain hardness and mechanical properties, such as modulus of elasticity and deformation at the linear limit on the force-deformation curve, and physical attributes, such as grain mass and major diameter. Grain orientation had no significant effect on the dependent variables. Moisture content had a very significant effect on me-chanical properties. From the statistical analysis of the data (ANOVA and DMRT), it was found that it is possible to distinguish between soft and hard wheat kernels based on dif-ferent parameters obtainable from the force-deformation curve. Hence, any one of these parameters may be used as a suitable indicator for grain hardness determination.

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In this paper, the behavior of a new type of auxetic composite (composite with negative Poisson’s ratio) consisted of polyester fibers and ABS tubes as reinforcement as well as polyurethane foam as matrix was investigated by finite element method. Furthermore, the effect of negative Poisson’s ratio and mechanical properties of auxetic composite under quasi-static pressure were analyzed and the results were compared with the published experimental works. Good agreements were found between the results. Considering stress-strain diagram, it is concluded that this type of composite can operate as a damping material due to the specific properties such as high shear strength, indentation strength toughness. So, the foresaid properties make them a great choice with high potential application in various industries. Also, the ways to get the effective parameters to achieve more negative Poisson’s ratio were investigated. The parameters include the foam density as well as material, diameter and distances between ABS tubes. The results show that with decreasing foam density and decreasing distances between ABS tubes, the negative Poisson’s ratio increases at first to reach the critical value and then decreases.

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Polymers are used in a wide range of industries. In this research, the mechanical behavior of polymers used in the glass industry has been studied. The investigated polymers included thermoplastic polyurethane (TPU), polyvinyl butyral (PVB) and sentry glas (SG). These polymers were subjected to tension and compression tests at different strain rates from 0.001 to 0.25 s^-1. Also, the mechanical dynamic properties of the polymers were extracted using the mechanical dynamic analysis test at a constant frequency. The tensile test results showed that the mechanical behavior of polyurethane is not dependent on strain rate, but SG is highly sensitive to strain rate. Also, with increasing strain rate, the fracture stress of SG decreased drastically. The pressure test results showed that TPU can withstand more stress. The glass transition temperature of TPU was lower than the other two polymers. Overall, it can be concluded that among the polymers studied in this research, TPU had better mechanical behavior.