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At present, the 2018 China New Car Assessment Program (C-NCAP) regulation puts requirements on the active safety performances of vehicles. New vehicles need to add active safety configurations to get a better achievement in the C-NCAP. The configurations include Forward Collison Warning (FCW) system, Auto Emergency Braking (AEB) system and so on. However, few vehicles are equipped with motorized seat-belts. When the vehicle is about to collide, the AEB system generates braking response before the driver. The deceleration caused by the emergency braking of the vehicle will affect the posture of the driver, such as causing the torso to lean forward and reduce the distance between the steering wheel and the driver. If the vehicle still collides after the emergency braking, the change of the driver's posture will produce adverse effects on the protection performance of the air bag and seat-belt. Through finite element simulation, this paper discusses the relationship between the pre-tightening levels of the active seat-belt and the posture of the driver during the emergency braking. Furtherly, a detailed explanation of the relationship between the pre-tightening levels and the injury of the driver's chest is made. The Total Human Model for Safety (THUMS) biomechanical dummy is used to simulate the driver and the LS-DYNA is used to calculate the case of a frontal collision. There are different scheme models in the simulation. In these models, the seat-belts are set with different pre-tightening levels, and different initial speeds are set for each level. After the emergency braking which generated by AEB system, the models still have the full-frontal collisions at a speed of 50km/h. The results show that when the vehicle is in emergency braking, the forward inclination of driver's torso is inversely proportional to the active seat-belt pre-tightening levels. After the collision, the damage degrees of the driver's chest are also different among the pre-tightening levels.

Electrochemical corrosion behavior of a thermal-sprayed Ni-Al-coated Q235 steel was investigated in the simulated soil solutions at different pH values using measurements of potentiodynamic polarization curves and electrochemical impedance spectroscopy as well as surface analyses including x-ray diffraction analysis, scanning electron microscope equipped with an energy-dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy. The results showed that the corrosion resistance of the Ni-Al-coated Q235 steel was dependent on the pH of the test solution. From pH = 3.53 to pH = 4.79, the corrosion resistance of the coated steel increased rapidly. In the pH range from 4.79 to 12.26, the corrosion resistance exhibited no significant change. At pH 13.25, the corrosion resistance of the sample was found to decrease. The calculated corrosion rate of Ni-Al-coated Q235 steel was lower than that of the uncoated Q235 steel and galvanized steel in all the test solutions. Over a wide range of pH values, the Ni-Al-coated Q235 steel exhibited extremely good corrosion resistance. The experimental data together with the potential-pH diagrams provided a basis for a detailed discussion of the related corrosion mechanisms of the coated steel.

The corrosion behavior of a thermal-sprayed stainless steel (SS)-coated Q235 steel has been investigated in simulated soil solutions using electrochemical measurements, x-ray photoelectron spectroscopy analysis, and scanning electron microscope. The as-received Q235 steel and galvanized steel for grounding grids were also examined for the purpose of comparison. The effects of pH value of testing solutions have been examined. The thermal-sprayed SS-coated steel showed the best corrosion resistance among the three kinds of materials. With increasing pH value, the corrosion resistance of SS-coated Q235 steel increased. In weak alkaline solutions, the SS-coated Q235 steel showed the largest polarization resistance (3.2 × 105 Ω cm2), the lowest anodic current density (1.4 × 10−2 μA/cm2), and the largest film resistance (4.5 × 106 Ω cm2), suggesting that the coated steel has the best corrosion resistance in weak alkaline environment. Related corrosion mechanisms are also discussed.

Electrochemical corrosion behavior of a thermal-sprayed Al-Si coated Q235 steel has been investigated in simulated soil solutions. The as-received Q235 steel and galvanized steel for grounding grids were also examined for comparison purpose. The effects of pH value of testing solutions have been examined. The thermal-sprayed Al-Si coated steel showed better corrosion resistance in acidic and neutral solutions than the as-received Q235 steel and galvanized steel, having the largest polarization resistance, the lowest anodic current density, and the largest film resistance. However, in strong alkaline solution, the corrosion resistance of the thermal-sprayed Al-Si coated steel degraded rapidly due to the change of corrosion product scale. Related corrosion mechanisms are also discussed.