In this research, the key properties of vacuum forming composite wheel house based on lightweight design including mechanical properties, stone impact resistance, vibration endurance, sound insulation performance, wind resistance deformation were studied and analyzed, those properties were compared and analyzed with mature injection molding and compression molding. Research result shows that comprehensive performance of the composite wheel house fender meets the technical requirements of passenger vehicle wheel house fender. Compared with injection molding products, the newly designed products have better stone impact resistance and sound absorption performance, with weight reduction of 22%. Compared with die pressing products, the new product has shorter development cycle and cost advantage.

With a car underbody protection panel as the research object, a solid model of the underbody protection panel was established using CATIA software. The finite element analysis software Hyperworks was used to simulate and analyze the static load and impact resistance performance of the car underbody protection panel, evaluate the effects of factors including fixed solutions, reinforcement structure, material selection and etc. The simulation results provide a theoretical basis for the design and material selection of the car underbody protection panel structure.

This paper introduced the process and performance of reaction injection molding polyurethane car trunk cover plate, and compared it with traditional car trunk cover plate. The results show that reaction injection molding polyurethane car trunk cover plate is easy to clean and daily maintain, it reduces the risk of sliding of items in the luggage compartment when the car is turning, improves the driving experience. At the same time, acetaldehyde is significantly reduced, and other properties also meet the requirements for trunk cover plate.

With the stress value, the maximum contact pressure and the compression force as evaluation basis, the influence of the straight line length of the return pipe joint and the return pipe on the assembly of the structure was studied by using the finite element simulation analysis method. With the increase of the length of the straight line, the stress value of the joint and the return pipe decreases gradually, and the maximum stress value of the joint and the return pipe is 650% and 295.2% larger than the minimum stress value, respectively. The maximum contact pressure of the inner liner and the outer liner also decreases gradually, and the maximum contact pressure of the inner liner and the outer liner is 384.9% and 290.2% greater than the minimum value. The pressing force gradually decreases, and the maximum value is 678.8% greater than the minimum value. The research results show that change of the length of the straight line has a significant impact on the assembly performance of the structure.

To solve the problem of performance degradation caused by abnormal rotor assembly, this paper analyzed the possible magnetic steel leakage and missing angle fault modes during the assembly process of the rotor assembly. The leakage mode can be prevented through surface magnetic detection, while the missing angle mode cannot be detected and recognized by surface magnetic detection equipment in the industry. Therefore, the paper proposed a method for error prevention and recognition through the analysis of the back electromotive force and vibration characteristic order of the motor, the method can identify the amplitude of higher characteristic order vibration of the motor that exceeding the standard value. In the actual production and manufacturing process, attention is paid to the collection of offline vibration signals of the motor for abnormal operation judgment. After practical verification, this method can effectively identify magnetic steel leakage and missing angle fault modes.

The application of post-treatment technology in the surface treatment of steel-aluminum mixture was studied by Scanning Electron Microscope (SEM), inductively coupled plasma emission spectrometer and cyclic alternating salt spray tester. The results show that the cold-rolled sheet and galvanized sheet on the car body form uniform and dense phosphating film after the new pretreatment process. After the new pretreatment process, a passive film was formed on the surface of aluminum plate. With the increase of aluminum in steel-aluminum mixture, the amount of slag in phosphating solution decreases gradually. When the treated material is only iron, the slag in phosphating solution is 2.5 g/m², and when all the treated materials are aluminum, the slag in phosphating solution is lower than 0.5 g/m². When the new pretreatment process is used to treat the steel-aluminum mixture, the concentration of all ions in the phosphating solution can be kept at a stable level. The adhesion test results of paint films of three aluminum plates meet the standard requirements. After 1 000 h salt spray test, the unilateral corrosion of cold-rolled plate is less than 2 mm, and there is no foaming and peeling of paint film. After 1 008 h cyclic alternating test of aluminum plate and galvanized plate, the width of unilateral corrosion expansion is less than 2 mm, and the paint film does not bubble or peel off.

To enable manufacturing enterprises and individuals to choose appropriate Predetermined Time Standards methods, increase the applicability and practicality of Predetermined Time Standards methods application process, this paper analyzed the methods of Modular Arrangement of Predetermined Time Standard (MOD), Methods-Time Measurement-1 (MTM-1), Methods-Time Measurement - Universal Analysis System (MTM-UAS) in terms of time accuracy, analysis efficiency, improvement supportability effect, application threshold and application standardization, the paper also provided reference suggestions for method selection and application.

In the production of a vehicle, the painting shrinkage appeared near the liftgate hinge gasket. This defect occurred frequently and needed to be polished and repaired on site, which greatly affected the production efficiency. The pollutant was determined to be methyl cyclosiloxane by gas chromatography, mass spectrometry and other tests. The cause is that when the silicone rubber gasket is baked in the paint workshop, small molecules of methyl cyclosiloxane are precipitated, which leads to paint pollution. According to this problem, the liftgate hinge gasket was changed from silicone rubber to ethylene propylene diene monomer rubber, which completely solved the problem of paint pollution.

The hot-rolled wire rods of 6056 aluminum alloy were solution treated at 470~600 ℃, water quenched and artificially aged. The effects of different solution temperatures on the mechanical properties, fracture morphology, metallographic and intergranular corrosion resistance of Al-Mg-Si-Cu aluminum alloy were investigated by tensile property test at ambient temperature, intergranular corrosion resistance test, combined with optical microscopy, scanning electron microscopy and energy spectrum analysis. The results show that Mg₂Si in the microstructure of 6056 aluminum alloy dissolves more fully into the matrix as the solid solution temperature increases, while the undissolved iron-rich and copper-rich phases do not show significant changes. The tensile strength increases with the increase of solid solution temperature, reaching a peak around 540 ℃. When the solid solution temperature increases to 570 ℃ and 600 ℃, the strength changes slightly, but the elongation first increases and then decreases with the increase of solution temperature. The intergranular corrosion resistance decreases with the increase of solid solution temperature.

In order to study the characteristics of residual stress distribution on DP980 high-strength steel treated by Laser Peening (LP), a finite element analysis model was established to analyze the influence of different LP times on the stress distribution both on the surface and in the depth of the material. Additionally, strenuous tests with different LP times were carried out, and the residual stress of samples was tested to verify the consistency of experiment and simulation results. By comparing the surface roughness of the samples before and after LP, it indicates that plastic deformation occurs on the sample surface, and a uniform residual stress distribution is generated on the surface after LP. In order to achieve the internal stress balance, a low-amplitude tensile stress is induced at the core of the sample along the depth direction. With the increase of LP times, the residual stress induced on the surface of sample rises, and a deeper influence layer is generated. In fact, the residual stress induced by LP on the material surface increases the micro-crack closure force inside the parts and then postpones the crack growth rate, thus improves the service life and reliability of parts effectively.

In order to address the issue of corrosion in the manufacturing and storage process of die cast aluminum alloy parts without coating on the surface, this article analyzed the corrosion mechanism and cause of die cast aluminum alloy parts, and elaborated on an anti-rust scheme suitable for die cast aluminum alloy, test and application research on anti-rust materials and processes were also carried out. Corresponding rust prevention measures were adopted for each link in the plan, including the use of water-based rust prevention materials and vapor phase rust prevention materials. After laboratory and vehicle verification, this anti-rust technology can effectively prevent corrosion in the manufacturing, storage, transportation, assembly and other processes of die cast aluminum alloy parts, and systematically solve the corrosion problem of die cast aluminum alloy parts.

This paper explored the influence of different preparation time and closed stage time on the air quality test results inside the car in HJ/T 400-2007 “Method for Determination of Volatile Organic Compounds and Aldehydes and Ketones in the Car”. The experimental results show that when the preparation time increases from 6h to 32h, the concentration of VOC substances in the air quality of the vehicle generally shows a decreasing trend. The initial concentrations of formaldehyde, benzene, ethylbenzene and styrene were low, and reached equilibrium rapidly with the extension of preparation time. With the extension of the blocking time from 16h to 32h, the concentration of styrene, ethylbenzene and benzene changed little, and the concentration of toluene, xylene, formaldehyde, acetaldehyde and TVOC increased gradually.

The traditional industrial robot rolling method relies heavily on manual adjustment, resulting in low debugging efficiency and difficult quality control. To address this issue, this article explored the application of industrial robot adaptive edge rolling tools in edge rolling pressing process and its effect on improving edge rolling quality. The effectiveness of industrial robot adaptive rolling tools in adaptively adjusting rolling pressure was verified through experiments, which can significantly improve production debugging efficiency. In addition, the article also discussed the effects of speed and pressure on the rolling quality, as well as how to ensure the safety of equipment operation through monitoring alarms. Research has shown that adaptive rolling systems can significantly improve the surface quality of rolling and pressing.