طراحی، ساخت و ارزیابی دو تیغه زیست مقلد برای کاهش انرژی موردنیاز برای برش ساقه گیاهان علوفه‌ای

در این تحقیق با استفاده از روش زیست مقلد (روش چگونگی انتقال راه‌حل‌های بیولوژیکی به روش مهندسی) دو تیغه جدید به منظور کاهش انرژی مورد نیاز برای برش ساقه گیاهان زراعی طراحی، ساخته و ارزیابی شد. در ساخت این تیغه‌ها از پروفایل هندسی پنجه جلویی آبدزدک و فک ملخ الهام گرفته شد. سپس انرژی مورد نیاز برای برش دو دسته از گیاهان علوفه‌ای (تغذیه‌ای و هرز) با استفاده از تیغه‌های جدید و تیغه‌های مرسوم (صاف و خمیده) مقایسه گردید. گیاهان علوفه ای تغذیه ای مورد آزمون شامل یونجه و شبدر و گیاهان هرز شامل خرفه، اویار سلام، تاج خروس، سلمک، نی و شالی بود. طبق نتایج تحقیق حاضر، اختلاف معنی‌داری در انرژی برشی تیغه های زیست مقلد ساخته شده در تمامی تیمارها نسبت به تیغه های مرسوم (صاف و خمیده) مشاهده شد. تیغه زیست مقلد آبدزدک، به‌طور متوسط 39.13 درصد انرژی مورد نیاز برای برش ساقه گیاهان را نسبت به تیغه صاف و 32.8 درصد نسبت به تیغه خمیده کاهش داد. با توجه به همه جوانب مورد بررسی، تیغه زیست مقلد آبدزدک عملکرد بالاتری نسبت به تیغه زیست مقلد ملخ برای برش گیاهان نشان داد و به‌عنوان نتیجه نهایی برای ساخت تیغه برش توصیه می‌شود.

Design and Evaluation of Two New Biomimetic Blades for Reducing the Shear Energy Required for Cutting Herbal Plants

Introduction;Optimizing the energy consumption in mechanized agriculture is becoming more important due to the limited energy sources in the world. In this regard, optimization of the cutting blades is presented in this study by modifying the geometric form of the blade to reduce the forage cutting energy. Hence, two new blades, inspired by the geometric profiles of front claws of mole crickets and teeth of grasshoppers were designed and built using the biomimetic method (the method for transferring biological solutions to the engineering ones). Finally, the new biomimetic blades were tested and compared with two other conventional blades (flat and bent blades) by cutting 8 different types of crops and weeds.;  Materials and Methods;The main idea of building one of the blades was inspired by the geometric forms of mole crickets ' scissorslike front legs and lower teeth of grasshoppers. Therefore, five adult mole crickets and five grasshoppers were collected from a farm in Kalate Naderi, Khorasan Razavi Province. In the next step, different images were captured from the front leg of mole cricket and tooth of grasshopper using the stereomicroscope (Nikon, SMZU, Japan). In the next step, the images were transferred to the image analysis software (Image J) and the boundary lines of images were selected. Then, the selected boundary lines were imported to SolidWorks software and the points on the selected curve were extracted. The obtained points were drawn in Matlab software and several fitting curves for the points were examined, e.g., Fourier function, Gaussian function, and polynomial function. According to the obtained results, the Gaussian profile was selected to design the blade with the highest correlation coefficient (R2=0.99), see Fig. 1d. To design the desired blade, a section of the Gaussian curve between points A and B were used. Finally, the biomimetic blade of the mole cricket and grasshopper were drawn in SolidWorks software (Fig. 1e). After designing the blades in the SolidWorks software, the biomimetic blades were built by a CNC machine.;Results and Discussion;In all the treatments, a significant difference was observed between the biomimetic blades and the conventional flat and bent blades according to the results of Tukey 's test at the level of 5%. The obtained results showed that there was no significant difference between the mole cricket and grasshopper blades at the level of 5% for cutting. According to the results obtained in this study, there was a significant difference at the level of 5% between the grasshopper and flat blades for cutting alfalfa, clover, amaranth, orach, and poaceae; as well as between the grasshopper and bent blades for cutting alfalfa, clover, nutsedge, and amaranth, also between mole cricket and flat blades for cutting alfalfa, clover, purslane, amaranth, orach, paddy, and poaceae and finally between mole cricket and flat blades in cutting alfalfa, clover, nutsedge, amaranthus, and paddy. In this regard, no significant difference at the level of 5% was observed between the flat and bent blades for all cutting treatment. The batches containing 6 stems were used for cutting the soft stems with low shear stress and the batches containing 4 stems were used for cutting thick stems with high shear stress.;Conclusions;The results obtained in this study indicated that the geometrical form of the blade has a significant influence on the amount of required shear energy. The mole cricket biomimetic blade reduced the cutting energy compared to the flat blade by 23.37% to 52.51% (with the mean of 39.11%) and compared to the bent blade by 10.46% to 52.46% (with the mean of 32.8%). The grasshopper biomimetic blade also reduced the cutting energy compared to the flat blade by 15.78% to 53.82% (with the mean of 33.59%) and compared to the bent blade by 2% to 46.29% (with the mean of 27.87%). According to the results of this study, the mole cricket biomimetic blade showed better performance in comparison with the grasshopper biomimetic blade for cutting the plants and as a final result could be recommended to build the plant cutting blades.