Addressing the issues of brake efficiency degradation and thermal fatigue cracking due to temperature rise in automotive disc brakes, this paper provides a systematic review of research advancements in temperature field analysis, fatigue life analysis, and heat dissipation structure optimization. It delves into the temperature field characteristics of brakes, uncovers the mechanisms behind thermal fatigue failure in brake discs, compares various heat dissipation methods for brakes, and summarizes optimization techniques for friction pair structures. The temperature rise of the brake is influenced by the driving conditions. The highest temperature of the brake disc is concentrated in the sliding area of the friction pair. The temperature field is strongly coupled with the stress field, and thermal stress induces thermal fatigue, which manifests macroscopically as cracks, while microscopically, it promotes crack propagation due to pre-existing defects. The primary heat dissipation mechanism is air convection, and forced cooling needs to be optimized for the optimal operating temperature. Optimizing the dimensions of the friction lining and brake disc, and improving the ventilation structure can significantly reduce temperature rise and extend service life.

To enhance the light weighting level of a certain commercial vehicle, AZ80 and AZ80-T6 magnesium alloy wheels are produced using high-strength magnesium alloy as the raw material through forging and heat treatment. During the vehicle road test, the AZ80-T6 magnesium alloy wheels passed the verification, whereas the as-forged AZ80 wheels exhibited cracking and air leakage. Taking the AZ80 magnesium alloy wheels with the shortest failure mileage as an example, a failure analysis is conducted. It is observed that the cracks ran along the rotation direction and are close to the rim edge. Through material physical and chemical inspection such as chemical composition, room temperature mechanical properties, and metallographic scanning, it is found that the wheel forging process is normal. Combining with the simulation analysis of the radial force conditions of the magnesium alloy wheels, it is discovered that the safety factor of the AZ80 magnesium alloy wheels is lower than that of the AZ80-T6 magnesium alloy wheels, and the insufficient strength is the main cause of failure. After replacing the AZ80-T6 state magnesium alloy wheels in the road test, the verification is passed.

To address the premature cracking of a certain type of transmission sleeve, a comprehensive failure analysis was performed using methods including chemical composition analysis, hardness testing, case-hardening depth measurement, metallographic examination and microscopic fractography. The results indicate that the failure was primarily caused by two synergistic factors. Firstly, excessive blocky ferrite in the core microstructure led to insufficient core hardness, resulting in poor hardness compatibility with the connected main shaft and sun gear. Secondly, the actual fillet radius at the root of the internal spline was below the design lower limit, which aggravated the local stress concentration effect. Under cyclic loading, the combined action of these two effects initiated and propagated cracks at the fillet of the internal spline tooth root, leading to the final failure. Based on these findings, corresponding improvement measures are proposed from the aspects of optimizing the material heat treatment process and controlling critical structural dimensions.

A fuel supply pipe bracket of a passenger car broke during the whole vehicle's durability test on a rough road. This paper conducts an analysis of the working conditions, material, CAE strength and durability, fracture surface and appearance dimensions of the fuel supply pipe bracket after the test. The material analysis and CAE strength and durability analysis both meet the enterprise standards. The fracture form is determined to be fatigue fracture through fracture surface analysis, and the fracture originated from the R corner at the root of the stamped protrusion on the part surface. The cause of the fracture is determined to be stress concentration caused by the too small R corner during the stamping process through appearance and dimension and CAE analysis. By improving the structure and process parameters of the stamping die, the problem of the too small R corner at the root of the stamped protrusion on the part surface was solved, and the overall feature dimensions of the part were completely consistent with the design model. The improved bracket did not fail during the durability test on a rough road.

To address the forged jourral fracfure of a mcdium-and-heary-duty vehicle, by analyzing the macro and micro morphology of the fracture of the forged journal, it is determined that the source of the crack is located in the center of the neck journal, and the crack spreads from inside to outside. It is judged that the crack is the thermal stress type cracking appearing in the quenching process, and the component segregation of raw materials also plays a certain role in promoting the cracking of the neck journal. The risk of quenching thermal stress cracking caused by excessive neck journal section size is reduced by the process adjustment of the neck position of the forged journal shaft: interior hole first and then tempering treatment, and the influence of the segregation of the core components of the neck journal on cracking is eliminated at the same time. By optimizing and adjusting the production process of forged journal, the risk of quenching crack is reduced and the reliability of the product is improved.

To evaluate the bolt-connection reliability of the integrated aluminum alloy frame for commercial vehicles, this study adopts a systematic method including torque statistics after fatigue test, Brinell hardness test of mounting surfaces, ultimate torque verification test of threaded connection pairs, and anti-loosening test under road load spectrum. The results show that after 1.5×10⁵ cycles of sinusoidal fatigue loading, the residual-torque retention rates of all critical connection points are higher than 70%; the hardness of mounting surfaces ranges from 65 to 115 HBW with uneven distribution and an average value of about 86.5 HBW. The equivalent Brinell hardness is converted from test data obtained using an impact ball with a diameter of 3 mm and an impact energy of 11 mJ, and the connection point of the lower control arm has the lowest hardness; the safety factors for M12~M18 bolt connections are no less than 1.55; under road-load-spectrum loading, the maximum attenuation rates of torque and axial force are 15.3% and 14.9%, respectively.

To address the issues of complex processing, poor weather resistance and easy rotting and deformation of natural wood grain when applied to automotive interiors, this paper systematically studies the core characteristics of three processes in the in-mold decoration (IMD) technology system: in-mold insert injection molding (IML), in-mold transfer (IMR), and insert injection molding (INS). To compare the process compatibility of gravure printing and screen printing in the preparation of wood-like textures, multiple sets of ink-level DOE tests were designed to optimize the visual effect of the texture, and comprehensive performance verification was carried out in accordance with the industry standards of automotive interior parts. The results show that the gravure printing + INS process, with a high tensile rate of 30% to 50%, a surface hardness of 3H+, and excellent weather resistance, has become the optimal choice for preparing complex large curved surfaces of automotive interiors imitating wood textures (without light transmission requirements). Screen printing +IML, the optimized ink hierarchy scheme (DOE 4-4) can achieve a low gloss of 7.3, with excellent matte effect and wood grain layering, making it the optimal process solution for the preparation of wood texture imitation with backlight/working indication. The prepared wood-textured imitation products have passed rigorous tests such as wear resistance, chemical reagent resistance, temperature shock, and damp heat. All performance indicators meet the requirements for automotive interior parts.

To address the height flushness between the long glass fiber-reinforced composite tailgate and side panel after high-temperature exposure, this study combines real-vehicle solar exposure tests, oven aging tests, and finite element analysis. Results indicate that the material creep is the primary cause of the long-term cumulative deformation of the tailgate under high-temperature conditions. Both the optimization of inner-panel reinforcing ribs and the extension of the reinforcement plate can effectively disperse local stresses and suppress creep deformation. A feasibility analysis identifies the reinforcement plate extension as the optimal solution, as it corrects flushness without requiring mold modifications, while offering low cost and rapid implementation. These findings provide valuable insights for the design of similar polymer tailgates.

Aiming at the unsystematic simultaneous engineering analysis for vehicle body final assembly and frequent late design changes and production line modifications in domestic auto enterprises, this paper adopts 3D simulation, process inspection, cost comparison and CAE verification. It analyzes body hanging holes, side skirts, doors, hinges, anti-collision beams and body accessories of a mass-produced vehicle, and proposes solutions to assembly interference, positioning deviation, poor sealing and insufficient operating space. The results show that advanced simultaneous engineering in design phase can avoid production risks, and tooling transformation is more economical. The optimized schemes meet requirements and provide reference for standard analysis and process optimization.

To systematically investigate the quality and reliability verification methodologies for automotive electronics manufacturing processes, this study designs a comprehensive validation framework spanning from discrete components and printed board assemblies to finished modules, in accordance with AEC-Q series standards, ISO/IEC international standards, and mainstream OEM requirements. By integrating quality and reliability requirements directly into the production workflow, an overall verification scheme is established, which explicitly delineates the specific quality and reliability testing items required at each stage of the automotive electronics lifecycle.