Experimental Study Of Mechanical Properties Of Corn Stalks

In order to research the mechanical properties of corn stalks in mature, this study collected corn stalks of jifeng96, xiangcaiyu2hao, yuyu23hao and een3hao, prepared the test samples and carried on the tensile, bending, shear and compression test respectively to study the effect of factors as different varieties, different internodes different loading-speed on the mechanical properties parameters of corn stalks. The results are as follows:(1) In tensile test, the maximum tensile force, tensile strength and elastic modulus of the different internodes of different varieties are different:the range of the maximum tensile force of jifeng96, xiangcaiyu2hao and yuyu23hao is respectively157.43291.86N,165.07～275.29N,236.43～340.71N; the range of the tensile strength of jifeng96, xiangcaiyu2hao and yuyu23hao is respectively40.79～40.79MPa,73.9173.91MPa,70.65to92.59MPa; the range of the elastic modulus of jifeng96, xiangcaiyu2hao and yuyu23hao is respectively9.57～22.32GPa,12.14～30.33GPa,8.56～8.56GPa; from the analysis of variance, we know that internodes and varieties have a significant or extremely significant influence on the tensile properties of corn stalks.(2) In bending test, when having internode, the average of max-load of the second, third, forth, fifth internode are respectively431.16N,369.92N,305.93N,260.54N; the average of bending strength of the second, third, forth, fifth internode are respectively4.97MPa,4.6MPa,4.27MPa,4.01MPa; the average of elastic modulus of the second, third, forth, fifth internode are respectively20.73MPa,19.13MPa,20.15MPa,20.55MPa; when having no internode, the average of max-load of the second, third, forth, fifth internode are respectively223.62N,147.89N,119.41N,96.99N; the average of bending strength of the second, third, forth, fifth internode are respectively3.41MPa,3.06MPa,2.70MPa,2.54MPa; the average of elastic modulus of the second, third, forth, fifth internode are respectively16.05MPa,15.74MPa,20.34MPa,24.69MPa; from the analysis of variance, loading-speed has little effect on the maximum load, bending strength and elastic modulus and the effect of internode on maximum load is associated with the case of having internode or not, while the gauge length has the biggest influence on the characteristic parameters of bending.(3) In shear test, when having internode, the average of max shear force of the second, third, forth, fifth internode are respectively2059.47N,1737.88N,1445.18N, 1295.97N; the average of shear strength of the second, third, forth, fifth internode are respectively6.08MPa,5.12MPa,4.90MPa,3.79MPa; the average of shear modulus of the second, third, forth, fifth internode are respectively2.48GPa,1.84GPa,1.71GPa,1.53GPa; when having no internode, the average of max shear force of the second, third, forth, fifth internode are respectively1897.44N,1389.66N,1178.97N,847.43N; the average of shear strength of the second, third, forth, fifth internode are respectively5.36MPa,4.54MPa,4.31MPa,3.02MPa; the average of shear modulus of the second, third, forth, fifth internode are respectively2.89GPa,2.31GPa,2.20GPa,1.89GPa; from the analysis of variance, the characteristic parameters of shearing will change with the internodes and the case of having internode or not; the influence of internodes and loading-speed on cornstalk shear test is very large, which also has a significant or extremely significant influence on the shear properties (the maximum shear force, shear sthength and shear modulus) of corn stalks.(4) The processes axial compression and radial compression of corn stalks are not exactly the same. In axial compression, load increases with the increase of displacement at first, then decreases and there must be some obviously twists and turns, after compaction, the load increases rapidly along with the displacement. In radial compression, the load increases with the increase of displacement, while growing slowly at first then faster without big twists and turns in the process. For both axial compression and radial compression, because of high moisture content, some liquid will flow out from the sample. Under the setted test condition and through the test, data processing and analysis of variance, it can be seen that under the different test conditions (moisture content, having internodes or not, loading-speed, internode), the influence of factors on compression properties is not the same, but you can be sure, these factors are important influence factors of corn stalk compression properties.