The objective of this study was to investigate some physical and mechanical properties of Osmancik-97 rice variety wi- despread cultivated in Turkey in order to determine needed designing parameters for handling and storage facilities. In this study, some physical and mechanical properties were evaluated as a function of moisture content in the range of 10- 14% d.b. Length, width, thickness, arithmetic and geometric mean diameter ranged from 8.27 to 9.01 mm, 3.10 to 3.48 mm, 2.05 to 2.26 mm, 4.47 to 4.92 mm, 3.75 to 4.13 mm, respectively as the moisture content increased; sphericity, grain volume, surface area, true density and porosity increased from 43 to 45%, 130.97 to 160.32 mm 3 , 38.68 to 46.91 mm 2 , 939.0 to 962.1 kg m -3 , and 36.61 to 41.97%; bulk density decreased from 595.5 to 560.5 kg m -3 ; the angle of internal fric- tion increased linearly from 29.70° to 32.53° with the increase of moisture content; the static coefficient of friction in- creased from 0.764 to 0.972, 0.524 to 0.702 and 0.576 to 0.764 for concrete, galvanized steel and wood surfaces, respec- tively; the poisson ratio and pressure ratio decreased linearly with the increase of moisture content. The data obtained from the study will be useful in the structural design of rice bin to calculate loads on bins from the stored material. Additional key words: angle of internal friction, bulk density, porosity, pressure ratio. Resumen

https://dialnet.unirioja.es/descarga/articulo/3278087.pdf

The effect of moisture content on physical and mechanical properties of rice (Oryza sativa L.)

This research was conducted to evaluate some mechanical properties and bruise susceptibility of nectarine (Prunus persica variety). Compression and impact tests were conducted to determine the mechanical properties and the bruise susceptibility depends on the direct mechanical damaging of nectarine fruit. Compression tests were carried out by using a compression test device at 1 mm min−1 load velocity. Deformation, bioyield point force, deformation energy, and Poisson's ratio were determined using compression tests data. Absorbed energy, bruise volume, and bruise susceptibility were determined by impact tests. Impact tests of nectarine were conducted by using a pendulum with a 50-cm arm length. These tests were carried out at two directions of nectarine, namely, impact from the bottom side and its cheek side and three drop heights (30, 40, and 50 cm) to obtain different impact energy levels. In addition to these data, dimensional properties, such as length, width, and mass, were also measured.

Selected Mechanical Properties and Bruise Susceptibility of Nectarine Fruit

In this study, the Poisson's ratio and Young's modulus of red bean grains were determined as a function of moisture content (5, 7.5, 10, 12.5 and 15% w.b.) and loading rate (3, 6, 9, 12 and 15 mm/min) for Goli and Akhtar varieties. Quasi-static compression loading was carried out, and both unit lateral extension and unit normal compression values were determined. Average Poisson's ratio values from 0.322 to 0.267 and from 0.406 to 0.340 were obtained for moisture levels ranging from 5 to 15%, for Goli and Akhtar varieties, respectively. Poisson's ratio increased from 0.257 to 0.332 and from 0.346 to 0.405 at loading rates of 3 to 15 mm/min, for Goli and Akhtar varieties, respectively. Young's modulus of elasticity decreased as moisture content increased and increased with increasing loading rate for both varieties. These finding will be useful in predicting the load deformation behavior of red bean grains.



PRACTICAL APPLICATIONS

Owing to the fact that there is not enough information about Poisson's ratio of grains, in this study, the goal function is to determine the Poisson's ratio of red bean ((Phaseolus vulgaris L.) grain during applied compression load under various conditions. In order to obtain Young's modulus and some other mechanical properties, Poisson's ratio of red bean grain needs to be known. These results may be used by manufacturers in order to design harvesting machines or other mechanical devices such as sorting and separating machines.

Determination of poisson's ratio and young's modulus of red bean grains

A functional relationship has been proposed foi describing the effect of moisture content on the modulus of elasticity of remoistened soybeans. Based on experimental results, constants in the model have been determined by non-linear regression. Data from the ex-periments and the proposed function are graphically compared.

A model for predicting the effect of moisture content on the modulus of elasticity of soybeans.

Knowledge of apparent elastic properties such as Poisson's ratio and elastic modulus of agricultural seeds are important for the prediction of their load-deformation behavior and design of their process machines. The object of this study was investigated to test the applicability of three different methods existing in elasticity theory namely Hook's theory, Hertz theory and Boussinesq's theory for evaluation of the modulus of elasticity of agricultural seeds, as well as to study its general behavior under compressive loads and selection of the best theory among three reviewed theories. As a case study, the results of comparison elastic modulus of wheat determined on the basis of using above three theories were considered. The obtained results showed that Hertz theory (Parallel plates contact) is more suitable because of good agreement between theoretical and experimental results of force deformation curve. Also, between the four testing methods of loading of wheat the cylindrical indenter and core specimens give the lowest value while the parallel plate's method shows the highest values.

Determination of the Modulus of Elasticity in Agricultural Seeds on the Basis of Elasticity Theory

A b s t r a c t. An investigation into the Poisson’s ratio and elastic modulus of African nutmeg as a function of moisture content and loading rate was carried out. Quasi-static compressive tests were conducted at moisture levels of 8, 11.2, 14, 17.4 and 28.7% (d.b.) in an axial loading orientation. Both unit lateral extension and unit normal compression values were determined. Average values of 0.512 to 0.275 were obtained for moisture levels of 8 to 28.7%, respectively. Effects of loading rates were also investigated and results show that Poisson’s ratio increased from 0.136 to 0.334 at loading rates of 1 and 7 mm min -1 , respectively. Elastic modulus was observed to decrease as moisture increased. Average values of 201.5 to 41.30 N mm -2 were noted for moisture levels of 8 to 28.7%, respectively. A similar negative trend was observed with loading rate. These finding could therefore be useful in predicting the load deformation behaviour of African nutmeg.

/pdf/determination-of-poisson-s-ratio-and-elastic-modulus-of-4j2ptz3u2b.pdf

G. W. W. Etekpe

Papers

Determination of Poisson's ratio and elastic modulus of African nutmeg (Monodora myristica)