The finite element analysis and topology optimization design of tractor gearbox shell casting under static conditions are carried out. The shell structure load is simple and does not consider fatigue, durability, reliability and other multi-body dynamics design requirements. Therefore, the optimization results have great limitations: only static analysis and calculation are carried out, and topology optimization calculation is carried out on this basis to reduce the amount of materials, Therefore, the optimized and improved tractor gearbox shell casting is only the optimal solution under static load.
In recent years, the combination of finite element analysis and dynamic coupling joint simulation has become a common method for structural lightweight. The finite element dynamic analysis is carried out through the load spectrum of tractor gearbox shell casting obtained by dynamic simulation. The objective function and constraint function are relatively single, but they are complex in the actual situation. Therefore, in the future work, we should define the multi-objective function and multi constraint conditions, and conduct more in-depth research in the optimization of multi-objective function, so as to obtain more advanced optimization methods.
The structural design of tractor gearbox shell casting involves many key technologies. Only the structural design of tractor gearbox shell casting is further prospected:
(1). Transmission and vehicle test. After the design of the gearbox is completed, it should be applied to the whole vehicle. Therefore, to verify whether the designed gearbox meets the use requirements, a large number of experimental studies need to be carried out on the whole vehicle, and the weak links of the gearbox structure should be found according to the experimental data for improved design. Therefore, the physical prototype experiment is of great significance to the optimal design of gearbox.
(2). The influence of vibration and noise on the casting of tractor gearbox housing. In practical work, vibration and noise will lead to fatigue and even affect human health. At the same time, it will also reduce the normal service life of tractor gearbox shell castings, and then affect the comfort of the vehicle and the service life of the whole vehicle. Therefore, it is of great significance to study the vibration and noise reduction of tractor gearbox shell castings. The commonly used method is the combination of experimental method and numerical analysis method.
(3). When the shell structure is in the conceptual design stage, we should try to use the topology optimization method to optimize the shell structure. In this paper, only volume constraints and mass constraints are considered in the optimal design of high-power tractor gearbox shell casting. In the later detailed design stage, the displacement constraints and stress constraints are added to the topology optimization, and then the shape and size of the shell structure are further optimized. Through the combination of various optimization methods, the performance of the shell mechanism is optimized.
(4). The influence of ambient temperature on the transmission of high-power tractor is considered. The casting of tractor gearbox shell is the key part of bearing power transmission. Its overall steady-state thermal characteristics directly affect the power transmission performance of tractor gearbox shell casting. The damage of some key parts of the shell may only be caused by too large thermal load, which has little to do with the strength and stiffness of the shell. Therefore, in order to solve the above problems, the steady-state thermal characteristics of the whole tractor gearbox shell casting can be analyzed by using the finite element software, and the distribution cloud diagram of the internal temperature field of the tractor gearbox shell casting structure can be obtained. Through the cloud diagram, the weak or surplus parts of the shell structure due to the influence of temperature can be found, which provides a basis for structural optimization. The heat balance system of tractor gearbox shell casting under different working conditions can also be established by using Simulink toolbox for simulation, so as to obtain the distribution cloud diagram of temperature field inside the shell.
(5). The fatigue life of tractor gearbox shell casting was studied and analyzed. In the actual work of the gearbox, under the action of internal and external loads under various working conditions, most of the damage is not caused by insufficient material stiffness and strength performance, but fatigue failure. Therefore, in order to prolong the service life of the gearbox, the research on the shell structure should focus on the fatigue strength. At present, mainly through experimental methods and numerical analysis. The former focuses on the upgrading and optimization of finalized products, and the latter is mainly the combination of finite element theory and fatigue theory, which is then applied to shell fatigue life prediction, focusing on the stage of product design and development.