1Purpose and significance

1.1 Research Background

For information on trucks using a combination of internal combustion engines and electric propulsion, see Hybrid electric truck.Electric Renault Midlum used by Nestlé in 2015.An electric truck is an electric vehicle powered by batteries designed to deliver cargo.Electric trucks have been around in niche application areas for over a hundred years, but more recently the advent of lithium ion batteries has enabled the range of electric trucks to increase to several hundred miles, making them of much wider applicability.Electric trucks are becoming an alternative to traditional trucks, while creating no local pollution. Due to the high efficiency of electric power trains, running costs are expected to be lower.Their simplicity is also supposed to make maintenance costs much lower.However, electric trucks are usually heavier than diesel trucks, the energy density of lithium ion batteries is far less, so very long range trucking requires recharging en route, causing delays, or the swapping of tractor units.

1.2 Current status of foreign research

In the 1960s, the United States and other countries used finite element methods to determine static characteristics such as frame strength and stiffness. In the 1970s, the US application of NASTRAN not only statically analyzed the frame, but also effectively optimized the body structure, improved its stress distribution, and provided a new idea for applying the finite element method to design the body structure. In the 1980s, Mitsubishi applied a related program to perform a finite element analysis of the body frame. After entering the 1990s, computer-aided analysis (CAE) technology is not only used for the simulation analysis of the frame structure, but also applied the topology optimization design in the initial stage of the body structure design, so that the initial design of the car body structure is no longer based on experience or improved structure. . In order to improve vehicle ride comfort, Ford Motor Company of the United States applied finite element analysis to new car Ramp;D projects and achieved satisfactory results. In 2004, it discussed in detail how to use the finite element method to analyze the modality of the body structure, and based on the analysis results, propose a reasonable frame structure improvement plan. In 2005, BALAacute;ZS GOMBOR established an ADAMS-based vehicle dynamic model and tested the test results with static.The mechanical results were compared and good results were obtained. In 2008, Koprubasi Kerem constructed a dynamic model of hybrid electric vehicles, and analyzed the longitudinal response of the model. Based on the analysis results, the model was improved to further improve the running performance of the vehicle. In 2010, Jagadeep Thota conducted a study of the impact load on the frame to determine whether its structural strength meets the requirements for safe use. At the same time, the research aimed to optimize the strength and reduce the mass of the vehicle body, and optimize the analysis of the overall structure, and the result is that the total mass can be reduced by 25%. In 2014,Goran N. Radoicic has achieved some results in the study of nonlinear dynamic characteristics. In the transient response analysis of the crane frame structure, the finite element method is applied to obtain the sensitivity characterization parameters.

1.3 Current status of domestic research

In 2007, Liu Yang et al. proposed a new method for constructing the finite element model of the frame, that is, using the plate element method. At the same time, in order to solve the problems of low frame strength and low rigidity, it also uses the topology optimization theory to analyze the car body skeleton, and finally develops a new finite element model. In 2009, Xu Xiaona of Nanjing University of Aeronautics and Astronautics analyzed the strength of the car body under five working conditions, found out the weak structure of the car body, and proposed corresponding improvement suggestions. Then, with the goal of reducing the body quality, the DOE analysis method was applied. To ensure the dynamic performance of the frame, the goal of light weighting the frame is achieved, and the DOE analysis method is feasible in terms of lightweight frame.

In 2010, Xia Xia of Harbin Engineering University solved the problem of cracks after using the model of a model of Changchun for 3 to 5 years. The random vibration of the crack was studied, and the dangerous area where cracks easily occurred was found, and random fatigue was carried out. Life study, find the cause of the damage to the frame. In 2013, Wang Yutao of Hunan University started from the prediction of the fatigue life of a certain type of dump truck frame. The whole life analysis of the frame was carried out. Combined with the simulation results of the vehicle dynamics model and the finite element modal analysis results, The fatigue life distribution map of the frame. In 2015, Su Ruiyi and others aimed at light weighting, combined with genetic algorithms, to construct a new mathematical model of frame topology optimization, and combined the actual situation with the optimization scheme to further improve the frame. After the improvement, the torsional rigidity and material utilization rate of the whole vehicle are improved, and the quality of the whole vehicle is reduced. In 2016, Li Fuqiang and others designed a strain letter on a self-propelled corn harvester.The number acquisition test collects the dynamic strain signal at the dangerous position and combines the power density fatigue analysis principle to successfully predict the fatigue life at the dangerous point, so it becomes a new prediction method.

1.4 Purpose

(1)Master and learn to design and optimize truck frames