| The key is that the industrial development of ramie ramie primary processing production mechanization, mechanization and technical difficulties in the production process that ramie stalk stripping and mechanical harvesting machinery sectors.Harvesting by hand, hand-stuffed access to traditional methods of ramie fiber, labor-intensive, low productivity, has been unable to meet the needs of contemporary textile fiber materials. In order to obtain high-quality lean linen, ramie improve production efficiency, mechanical harvesting and mechanical stripping system is the most effective way. Currently, researchers in the design of ramie stalk harvesting equipment stuffing process, the main consideration is to achieve by mechanical stripping and cutting function, ignoring the study of the mechanical properties of ramie stalk under external loads. Ramie exist in the actual bone hemp stalk stalk mechanical harvesting ramie stripping process is difficult to remove the net system and stem stems from unclean problem that affects the quality and efficiency of lean production and processing of hemp to a certain extent. Therefore, a study the mechanical properties of the separation of stem and leaf of ramie, ramie stalk existing mechanical harvesting, stuffed and plastic extrusion equipment to provide effective technical parameters and the optimization and upgrading of important theoretical significance.In order to reveal the phloem and xylem ramie stem fracture energy distribution separating impact loadingand investigate distribution law of the leaves connecting force and the impact fracture energy of ramie stems, with the second quarter of harvested hemp as test subjects, conducted two sets of experiments. Test 1, according to the standard of GB/T 1843-2008 with a TF-2056 B Izod impact testing machine, the ramie stems varying in moisture percentage were struck in different parts. Test 2, the static tensile test and dynamic impact fracture test were carried out to obtain the impact fracture energy and connection force of the stems leaf, different parts of the petiole which connect the ramie leaf and stalk with HD-B604-S computer of servo tensile testing machine and TF-2056 B Izod impact testing machine according to the standard of GB/T 1040-2006 and GB/T 1843-2008.The first group experimental result showed that when the moisture is 84.04%, the impact fracture energies of ramie from top to bottom and the xylem of ramie stalk part were in the range of 0.1860-0.7460 J and 0.0550-0.29100 J respectively. Meanwhile, the average impact fracture energy of the standard samples from the top to bottom was 0.0571, 0.0520 and 0.0528 J, and that of the pectin adhesive layer was 0.3072, 0.2165 and 0.1662 J. In the moisture percentage of 84.04%, 82.37%, 81.71% and 73.18%, the average impact fracture energy of the bottom was 0.0571, 0.0549, 0.0543 and 0.0528 J; the xylem of ramie stalk part was 0.5067, 0.4404, 0.4227 and 0.4031 J; and the woody bottom parts was 0.0240, 0.1824, 0.1676 and 0.1658 J. The results stated that with a decrease in moisture content, the impact of the lower portion of the fracture toughness of Ramie stalk gradually becomes smaller. However, with the moisture content decreased, stalks gradually dry, phloem and xylem become withered and adhesions, and ramie stalk separation showed poor results. The second group experimental result show that: the maximal average connection force of stalk leaf is 14.492 N, the average connection force in the central part showed a maximal value than that in the top and in the bottom, the bottom part showed a minimum value. the maximal average impact fracture energy of stalk leaf is 0.042 J, the average impact fracture energy in the central part showed a maximal value than that in the top and in the bottom, the bottom part showed a minimum value. The size of the stalk leaf from the central and the top increased with the increase of the petiole diameter, at the same time, the connection force and the impact fracture energy increased in overall and showed a little fluctuation in local part. These two sets of Experimental studies were ramie stalk harvesting, storage, selection and design time stripping low-power high efficiency separation mechanism and ramie stem defoliation institutions and ramie joint harvest defoliants institutions designed to provide a theoretical basis.To further investigate the mechanism of separation of ramie stalk, according to other scholars ramie stalk experimentally measured density, elastic modulus, Poisson’s ratio and other parameters of the test article used in a standard pattern ramie stalk a simplified two-layer composite laminates model, ABAQUS finite element software for phloem and xylem ramie stalk numerical simulation analysis. Simulation of two different materials under impact loading stress, strain and energy changes, revealing the phloem and xylem separation mechanism ramie stalk. The experimental results and numerical simulation results were compared seen the error is 8.9%, which should permit the separation of ramie stalk impact energy is reasonable.The main contents and conclusions are as follows:(1) The impact fracture toughness ramie stem research using stem ramie impact tester impact fracture energy test conducted to determine the relationship between energy changes stem fracture process, draw the appropriate test parameters and numerical processing software(origin under impact loading, separation fracture energy distribution of phloem and xylem) numerical fitting, drawing curves, revealing ramie stalk;(2) Study the mechanical properties of ramie leaf, using tensile testing machine and impact testing machine, to be distributed in different parts of the connecting stalk ramie Mama and petiole were static tensile test and dynamic impact fracture, respectively, to obtain stem leaves and stems connecting force impact fracture energy range of values, and the use of numerical processing software(origin) numerical fitting, drawing curves, reveal ramie leaf connecting force and impact fracture energy distribution;(3) Ramie stalk composite low-impact load stratification research, applied ABAQUS finite Ramie Stalk double composite material layered simulation model to simulate the process of cracking and delamination bast fiber layer and the substrate and the availability of xylem stress, displacement cloud layers of material and strain energy distribution curve, ramie bast fiber layer and stem xylem simplified model of composite laminates, separation hierarchical simulation model with the simulation results to prove ramie stalk composites the damage and fracture with accuracy and authenticity, and the energy and force the stress distribution and the simulation results presented during the experiment were analyzed. |
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