Mechanical Characteristics Analysis of Grinding Plate of Food Waste Grinding Mill Based on ANSYS Workbench

Food waste accounts for 30% - 50% of domestic waste, and its centralized treatment is difficult. For commercial places with large production of food waste, it is a better way to use grinding mill to crush food waste and then discharge it into sewer. The mechanical properties of grinding plate are the decisive factors affecting the performance of grinding mill. In this paper, the static analysis and modal analysis of the grinding plate of commercial grinding mill are carried out. The results show that: under the rated load, the maximum equivalent stress of grinding hammer is 83.4mpa, the maximum equivalent stress of cutter head is 77.6mpa, which meets the design requirements, but the stress is relatively concentrated. The lowest modal vibration frequency of the lapping plate is 456.2hz, and the lapping plate will not have resonance damage under normal conditions.

Cutter Head Approximation Machining Method of Line Contact Spiral Bevel Gear Pairs Based On Controlling Topological Deviations

To improve the meshing performance and increase the bearing capacity and service life of spiral gear pairs, the cutter head approximation machining method based on controlling topological deviations was proposed to solve the problem where line contact spiral bevel gears with tapered teeth depth cannot be directly machined by cutter heads. First, the mathematical model of line contact conjugate flanks was established, and meshing equations and conjugate flank equations of bevel gear pairs were derived. Second, the gear tooth flank was set as the datum tooth flank for priority machining, and the pinion theoretical tooth flank which is fully conjugate with the gear tooth flank and the pinion machining tooth flank matching with the gear were solved. Then, the geometric topological deviations model of the comparison between the pinion machining tooth flank and its theoretical tooth flank can be established. Finally, with the pinion machining tooth flank approaching its theoretical tooth flank as the modification, the additional cutting motions and machining compensation parameters of cutter heads were obtained to control the pinion machining tooth flank deviations and reduce them to the allowable deviations of its theoretical tooth flank. The contact simulation analysis and rolling test verified the correctness of the line contact conjugate flank model and feasibility of the cutter head approximation machining method.

Experimental Research on the Adhesion Characteristics of Clay to Structures with Different Materials

When the shield machine passes through the clay layer, the clay debris cut by the cutter head usually adheres to the surface of the cutter head and is easy to form mud cakes after extrusion, which affects the safety and efficiency of construction. For the structure made of different materials, due to the different surface properties, the adhesion characteristics of clay are also different. So, selecting proper materials for the soil contacting parts in the shield machine can effectively reduce the adhesion between the structure and soil, decrease the clay adhering to the surface of the shield cutter, and reduce the possibility of further productions of mud cake. Therefore, studying the adhesion properties of clay to different materials and understanding the adhesion rule of clay to soil contacting structures are of guiding significance when selecting the materials of soil contacting parts. In this paper, the adhesion properties of cohesive soil to commonly used construction materials were studied by a self-made adhesion test device, including steel, iron, copper, aluminum, and engineering plastics (polyamide). According to the findings, the separation process of adhesion between soil and the structure by an external force can be divided into four stages, which are the adhesive elastic development stage, adhesive plastic development stage, failure stage, and detachment stage. The adhesion forces and the amount of soil adhered to the structures made of the selected materials are found to vary from each other. The adhesion forces ranked from high to low are, respectively, found on the iron, plastic, aluminum, steel, and copper surfaces. The material with the most amount of adherent soil is aluminum, followed by iron, steel, copper, and plastic.

Performance Evaluation of Diesel Engine Operated High-speed Chaff Cutter

Dairy farming has become one of major sources of income for farmers. To maintain a large dairy farm, fodder must be available in palatable form at every point of time in sufficient quantity. To ensure that the ready fodder is available for cattle, a high-capacity chaff cutter is necessary. A high speed and hogh-capacity chaff cutter procured from the local market and tested for its performance. The machine consisted of a flywheel type cutter head which was mounted on the rectangular platform. The cutter head consisted of three rectangular plain knives fixed 120° apart on a circular disc of 440 ϕ. The feeding assembly was mounted with three feed rollers viz., upper, low, and additional. Chute type feeding mechanism was provided. The machine was operated by a 3.73 kW diesel engine. The ‘v’ belt was provided for power transmission from engine to cutter head with a reduction ratio of 1:0.32. Feed rollers were driven by bevel and spur gears. Short run and long run evaluation of the machine were conducted for napier grass and dry jowar. The variation in length of cut pieces was found to be 8.39% and 5.78% for dry jowar and napier grass, respectively. Quality of cut was calculated and found to be -0.80 for dry jowar and -0.53 for napier grass. The average efficiency of the machine was found to be 86.87% and 88.93% for dry jowar and napier grass, respectively. The average diesel consumption was found to be 0.69 l h-1.

Water Saving Control of Turfgrass Irrigation Robot Using Genetic Simulated Annealing Algorithm

Artificial intelligence through the robotic system offers a solution to the quest for an autonomous system with high cutting efficiency for lawn mowing. Because of the current trimming and maintenance operations on grasslands and gardens, it is essential to develop autonomous and efficient lawn pruning electromechanical equipment. This paper describes the design and construction of a high-performance automated grass trimming and irrigating robot. This device cuts and irrigates grass automatically with little human intervention. A genetic simulated annealing algorithm was employed to optimize motor parameters, specifically design a set of mowing mechanisms and mowing height adjustment system. The prototype was tested, which mainly includes the running status evaluation of the walking module, the mowing module, the cutter head lifting module, and the collision detection module. This robot can save water while watering the lawns, reduce labor costs, and improve mowing efficiency. We note that the proposed system can be implemented on a large scale under natural conditions in the future, which will be helpful in robotics applications and cutting grass on lawns and playing grounds.

Mechanical Aspects of Construction of New TBM Tunnel Under Existing Structures

It is inevitable for the construction of subways to pass under the existing structures in the city; this will cause settlement of the existing structures and affect their safety. The soil is a complex mixture, and hence it is difficult to determine the damage caused by construction using tunnel boring machine (TBM) method to the stress balance of the surrounding soil. Normally, settlement and uplift of the surface are caused during tunneling. Therefore, large-scale 3D simulations are needed to study the interaction between mechanically driven tunnel construction and the surrounding soil to estimate the expected settlement and related damage risks to the existing structures, especially in tunnel construction in urban areas. Qingdao Metro Line 1 in the Haixiao section (Xiaocunzhuang and Haiboqiao stations) was taken up as the research object to study the trend and degree of the effect of TBM tunnel construction using the numerical simulation software Midas GTS NX. The numerical simulation results and measured data were used for the reliability analysis to study the influence of different digging speeds and pressures in TBM construction on ground subsidence, and the effect of vibrations generated at the tunnel face by the TBM cutter head on the ground structure. It is shown that when other factors remain unchanged, the faster the driving speed, the smaller the ground settlement; the higher the surrounding rock pressure, the smaller the ground settlement. The vibration of the ground structure caused by the TBM cutter head complies with the relevant specifications. During construction, the driving parameters should be selected suitably depending on the available budget.

Research on the Prediction Model of Shield Advancement Rate in Sandy Cobble Ground of Beijing

The long distance and tight construction period of the earth pressure balance shield tunneling in Beijing sandy cobble ground have a very positive impact on grasping the construction progress and improving the organization efficiency. Based on the real-time monitoring data of on-site earth pressure, cutter head speed, total thrust, screw conveyor speed, and cutter head torque, this study investigated the correlation between the shield advancement rate and the above parameters based on multiple nonlinear regression analysis method, which lay down the foundation of shield advancement rate prediction. The prediction model achieved satisfactory results and was further applied to an airport project. The results show that it is of guiding significance to use multiple regression method to establish shield prediction model and put forward the best advancement parameters to ensure the construction progress. The order in which the four operational parameters affect the advancement rate is total thrust, cutter head torque, screw conveyor speed, and cutter head speed. When the advancement time is greater than 57 min, the average advancement rate and daily progress are highly positively correlated. The research provides a reliable basis for the advancement rate prediction, safety control, and parameter optimization of shield advancement in similar ground.