To effectively evaluate the fatigue life of in-wheel-motor-driven electric vehicle steering knuckles, virtual iterative analysis of suspension multi-body dynamics modeling and road spectrum signals is conducted based on the measured road load spectrum, form which the input file of steering knuckles load spectrum is obtained. Fatigue life analysis on the steering knuckle is conducted by combining the inertia release results, material S-N curve and Miner linear cumulative damage criterion, and Fatigue tests are conducted on the steering knuckles for verification. Findings from both simulations and experiments indicate that the primary fatigue risk areas are at the interfaces between the steering tie rod and the lower shock absorber connecting rod. The steering knuckle design satisfies the requirement for a fatigue-free lifespan over a diriveing distance of 16×104 km.

To meet the small offset barrier crash performance requirements of both McPherson and double wishbone front suspension system, this paper analyzes the cause of deformation pattern and discrepancy of results in 25% offset collision condition of both McPherson and double wishbone front suspension. The vehicle is optimized structurally by taking measures such as adding energy absorption zone at the front end of doorsill, wreaking the front beam and A-pillar front segment, and setting the buffer zone of the front end of door. Effectiveness of these safety strategies and optimization measures have been verified by LS-DYNA simulation and real vehicle test, in which the vehicle structure grade is rated as excellent.

To study the head, neck, and chest injuries of Q1.5 dummy when restrained by an infant carrier under different frontal collision acceleration waveforms and whether the seat belt is pre-tightened and limited by force, three different real vehicles are selected to obtain B-pillar acceleration curves according to GB 11551—2014 “Passenger Protection in Frontal Collisions of Vehicles”. The acceleration curves are simulated and reproduced using an acceleration slide table, and the Q3 dummy’s scoring index in the frontal 100% overlapping rigid barrier collision test of the “C-NCAP Management Rules (2024 Edition)” is used as reference to score the Q1.5 dummy in test. The results indicate that during a collision, when the seat belt is pre-tightened, the diagonal upward tension generated by the shoulder strap can cause significant impact on the head; when the collision acceleration is consistent, the pre-tensioning of the seat belt has a greater impact on the peak combined acceleration of the head and chest, as well as the 3 ms peak, HIC₁₅, the peak waist belt force, the neck F_x-min, and M_y-min, than the force limit. The limiting effect of the peak shoulder belt force is greater than the pre-tensioning; the factors that affect dummy injury, from high to low, are collision acceleration waveform, whether the seat belt is pre-tightened, and whether the seat belt is force limited; for all parts of the dummy’s body, the chest substains greatest damage and the neck substains the least damage.

In order to study the protective effect of seat cushion restraint for occupant in reclined sitting in front impact，the sled tests were carried out with 10° and 27° seat cushion, seat cushion with airbag respectively to. The results show that the cushion airbag has no protective effect on occupant in reclined sitting. When the seat cushion angle is increased from 10° to 27°, the thoracic axial force of the 12th thoracic vertebrae (T12) in the rear occupant in reclined sitting can decrease by about 40%. The maximum chest deflection is located on the buckle side, and it transfers to bottom and increases with the increase of the seat cushion angle. When the seat cushion angle reaches 27°, the maximum deflection can exceed the high performance limit by 16.9%. Therefore the seat cushion angle should be selected between 10° and 27° to balance the thoracic and chest injuries for the rear zero gravity seat. The angle should be increased when the T12 axial force is too large, and the angle should be reduced when the chest deflection is too large.

To reduce the impact of Day Ⅱ crescent pelvic fractures in pedestrian traffic injuries, finite element analysis is used to investigate the biomechanical influences of Day Ⅱ Crescent Fracture Dislocation of Pelvis (CFDP) with different fixation systems. Based on a human pelvic finite element model, the pelvic model with fracture and four different fixation systems for Day Ⅱ CFDP are constructed according to human anatomical theory. These fixation systems include: one sacroiliac screw combined with one iliac screw (S1+I1), two sacroiliac screws combined with two iliac screws (S2+I2), three reconstructive titanium plates (P3), and one S₂AI screw combined with two iliac screws (S₂AI1+ I2). The advantages and disadvantages for the different fixation systems are comprehensively evaluated by the overall stiffness and stress of the pelvic model, the difference on the stress of iliac bone and internal fixation, and the difference on the stress and displacement of the fracture line. It is found that the stiffness of pelvic model with P3 solution and S₂AI1+ I2 solution is higher than that of the other two internal fixation systems. In addition, the stress distribution on the undamaged side predicted by the pelvic model with P3 is also closer to that predicted by the normal model without fracture. However, the highest stress values on the reconstructed plate and the posterior inferior iliac spine are also predicted by the pelvic model P3 fixation systems, because of the direct contact between the reconstructed plate and cortical bone. This direct contact is also not conducive to the healing of the fracture. The stress and displacement distribution on fracture line predicted by the pelvic model with S₂AI1+ I2 are closer to that predicted by the normal model without fracture. For the treatment of Day Ⅱ CFDP, it is recommended to choose S₂AI sacroiliac screw combined with 2 iliac screws for internal fixation, which can achieve a firm fixation effect without adding other internal fixation systems.

In order to study the non-contact injury of occupant in front collision in wide-angle sitting, the sled tests is conducted by adjusting the backrest angle and seat cushion angle, and using the airbag inflation delay and the enveloping type airbag. The results show that the risk of brain tissue shear failure, neck bending moment injury, heart aorta rupture and thoracic vertebral compression rupture increases in the occupants in wide-angle sitting，which cannot be effectively solved by timely inflation of airbag and enveloping airbag. It is further pointed out that it is a research direction to adopt the combination of timely inflation of front airbag and knee airbag according to the occupant's sitting posture sitting in front seat for the occupant in wide-angle sitting.

This review aims to delve deeply into biomechanical properties, biomechanical testing methods and injury biomechanics of brain tissue, it aggregates the research contributions of scholars worldwide to analyze the material mechanical testing approaches and biomechanical features of brain tissue. Also, the constitutive models and material properties used for brain tissue simulation of the head finite element model in the published literatures are summarized in this paper. These insights serve as a valuable reference on development of head finite element models, and also provide a certain basis for investigating of the injury mechanism and prediction of brain tissue.

By installing the four-hole probe on the hood of a vehicle and some pressure taps on the surface of the vehicle to collect the wind flow parameters such as velocity, yaw angle, turbulent intensity, turbulent length scale, spectra etc.. In this study, transient wind characteristics on two test sites (Hainan Automobile Proving Ground and Yancheng Automobile Proving Ground) are investigated. The results showed that there are significant differences in the wind flow characteristics between the test site and wind tunnel experiments and numerical simulations. The wind velocity in the test site fluctuates within the range of ±4 m/s, the yaw angle fluctuates between -5° and 5°, and the yaw angle distribution follows the standard normal distribution, the turbulence intensity is almost in the range of 2%~10%, the turbulent length scale is 2~20 m, and the measured spectra show a good correlation to the empirical von Kármán spectra.

To enhance the fuel economy of the certain series-parallel hybrid commercial vehicle, a control strategy for optimizing engine speed based on the overall system efficiency has been proposed. This strategy comprehensively considers factors such as engine fuel consumption, planetary gear set mechanical losses, power losses during motor generation/driving/idling, controller power losses, and the conversion relationship between mechanical and electrical energy. Mathematical and control models for the series-parallel hybrid powertrain system have been established, with the objective of maximizing powertrain efficiency. Through iterative analysis of vast amounts of data, optimal solutions for engine speed and torque have been obtained. Simulation results indicate that, compared to a speed control strategy based solely on optimizing engine efficiency, the proposed strategy for optimizing overall system efficiency reduces vehicle fuel consumption by 7.9% under cyclic operating conditions. Finally, a series-parallel hybrid powertrain test bench is set up to verify the effectiveness of the control strategy, and the optimization effect on fuel economy is found to be significant.

To improve vehicle economy, this paper proposes a single planetary array hybrid system. Taking the heavy commercial tractor as the research object, the key parameters of automotive components are designed according to power performance indicators. The optimal control of the engine is taken as the basic principle, and the switching principles of the top-level working mode and sub-working mode of the vehicle are formulated. The mode switch strategy control program is written using Simulink, and the vehicle economic simulation model is established using Cruise. The results show that fuel consumption of the hybrid vehicle is lower than that of the traditional fuel vehicle in the fast transportation and coal transportation condition.