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This paper proposes an integrated lane-change trajectory planning method for advanced driver assistance system of connected and automated vehicles. First, the time-based quintic polynomial automated lane-change model is presented, which could adjust longitudinal and lateral velocity simultaneously. By tuning the lane-change duration and longitudinal displacement in the lane-change model, the lane-change reference trajectories satisfying the demands of safety, lane-change duration, travel distance, and comfort were derived under traffic-free condition. All feasible reference trajectories compose a trajectory map, which includes different driving situations, such as quick and comfortable or sudden and safe lane change. Second, the lane-change constraints induced by surrounding vehicles are introduced. The effects of surrounding vehicles on the lane-change performance are investigated by adjusting the speeds and initial gaps of preceding and rear vehicles. In addition, the initial velocity of the host vehicle is optimized to maximize the area of the trajectory map to enable a safer lane change. Finally, within the derived trajectory map, an optimal lane-change trajectory eliminating potential collisions is calculated by minimizing the lane-change duration, travel distance, driving comfort, and fuel consumption.

In this paper, fatigue damage analysis and structural improvement of a commercial vehicle cab were carried out, in which a simulation technique and durability road tests were combined. A full-scale finite element model of the cab was established and then validated by means of physical testing and analysis of its stiffness and its modal performance. The loading spectra, in accordance with the durability road test, were obtained by adopting the virtual iteration method. With the established finite element model, the stress distributions in the cab under unit excitation were determined. The obtained stress distributions were then used to assess the total fatigue life of the cab by employing the strain–life (ε–N) method; thus, the critical regions were determined. The results showed that some components near the pillars and mounts are easy to damage because of the stress concentrations. It was also demonstrated that the predicted regions are reliable, which was verified by comparison with the physical durability road tests. Finally, structural improvements in the critical structures were made; the fatigue life assessment of the improved cab showed an obvious improvement in its durability performance.

The primary problem in the finite element analysis of polyurethane jounce bumpers, bumper stops, or similar structures is the identification of a mathematical model for the constitutive material. The densities of the exterior polyurethane area and the interior polyurethane area usually differ owing to the manufacturing process. This difference results in inaccuracy when predicting the mechanical behavior of the jounce bumper and bumper stop if a homogeneous material model is used. Thus, this work proposes a stratification method for finite element analysis of a polyurethane jounce bumper. The polyurethane structure was divided into three regions (the ‘skin layer’, the ‘transition layer’, and the ‘core area’) with different material properties. A foam model was utilized as the constitutive relationship. The foam model coefficients of the core area were obtained by a curve-fitting process using uniaxial compression test results. Subsequently, the material properties of the skin layer and the transition layer were also obtained. The finite element analysis results show that the proposed stratification strategy improves the prediction of the deformed shapes of the polyurethane jounce bumper. Furthermore, the calculated load–displacement curve is reliable for small to medium strains (0–0.4). Therefore, the proposed stratification method can be applied to enhance the reliability of jounce bumper simulations and to simplify the design process.