Study of Suspension Parameters Matching to Enhance Vehicle Ride Comfort on Bump Road

In this study, the parameters of the MacPherson front suspension and the E-type multilink rear suspension are matched to enhance the vehicle ride comfort on bump road. Vehicle vibration and suspension stiffness are analyzed theoretically. In the simulation study, the influence of the front and rear wheels on the vehicle vibration is considered, so the time-domain curves of the front and rear seat rail accelerations are processed by adding windows with two different window functions. The resulting ΔRmsLocal and ΔRmsGlobal are used as evaluation indexes of the vehicle ride comfort. The sensitivity analysis yields the magnitude of the influence of the suspension parameters on the evaluation indexes. In addition, the trends of ΔRmsLocal and ΔRmsGlobal with bushing stiffness at different vehicle speeds are discussed. The results show that longitudinal ΔRmsLocal and ΔRmsGlobal of the seat rails are influenced by the bushings mostly, while the vertical ΔRmsLocal and ΔRmsGlobal of the seat rails are influenced by the spring and shock absorber mostly. The trends of ΔRmsLocal and ΔRmsGlobal with bushing stiffness are influenced by the speed of the vehicle. Finally, the vehicle ride comfort is enhanced after optimization and matching of the suspension parameters by NSGA-II optimization algorithm.

Research and Analysis of the Propagation of Vertical Vibrations in the Arrangement of a Vehicle Seat—A Child’s Seat

This paper deals with the issues of the impact of vertical vibrations on a child seated in a child seat during a journey. Its purpose was to assess the impact of fastening the child seats and road conditions on the level of vibrations recorded on child seats. The paper describes the tested child seats, the methodology of the tests and the test apparatus included in the measuring track. The tests were carried out in real road conditions where the child seats were located on the rear seat of a passenger vehicle. One was attached with standard seat belts, and the other with the ISOFIX base. When driving on roads with three types of surface, the following vertical accelerations were measured: seat of the child seats, the rear seat of the vehicle and the ISOfix base. The recorded accelerations were first analyzed in the time domain and then in the frequency domain. Three indexes (r.m.s, rmq and VDV) were used to assess the vibration comfort. Research has shown that the classic method of fastening a child seat with standard seat belts is more advantageous in terms of vibration comfort. Calculated indicators confirmed the negative impact of separating the child seat from the rear seat of the vehicle using the IQ ISOFIX base.

Injury Risks of Rear Occupant in Typical Four-door Type of Pick-up Truck under Vehicle Collision

This research explores the injury risks of occupants in four-door type of pick-up truck using experimental based collision with Hybrid III dummy for occupant injury indicators. The full-sized crash laboratory was developed to conduct full frontal impact based on standard regulation. To verify performance of full-sized crash laboratory and vehicle deceleration, low and high speed tests were conducted at the same vehicle. The Hybrid III dummy with head and chest sensors was used at the rear outboard seat during high speed test. Consequently, the deflection and thoracic viscous criteria, which represent the chest injuries, are up to 93 mm and 3.96 m/s, respectively, high beyond the standard requirement. Moreover, the most important finding of this research is that the four-door pickup truck is subjected to the 2nd impact up to 116.51 G at dummy head with higher resultant acceleration than the 1st impact (65.62 G) due to the limited space behind the rear headrest and thinner backrest of rear seat. This research also investigates the post-crash results to illustrate the suggestive idea for improving crashworthiness of future design resulting in mitigation of occupant injuries.

Comparison of Motor Vehicle Collision Injuries between Pregnant and Non-Pregnant Women: A Nationwide Collision Data-Based Study

We compared the independent predictive factors for moderate and severe injuries, along with characteristics and outcomes of motor vehicle collisions, between pregnant and non-pregnant women. Using 2001–2015 records from the National Automotive Sampling System/Crashworthiness Data System, we selected 736 pregnant women and 21,874 non-pregnant women having any anatomical injuries. Pregnant women showed less severe collisions, fewer fatalities, and less severe injuries in most body regions than non-pregnant women. In pregnant women, the rate of sustaining abbreviated injury scale (AIS) scores 2+ injuries was higher for the abdomen only. For non-pregnant women, rear seat position, airbag deployment, multiple collisions, rollover, force from the left, and higher collision velocity had a positive influence on the likelihood of AIS 2+ injuries, and seatbelt use and force from the rear had a negative influence. There is a need for further development of passive safety technologies for restraint and active safety features to slow down vehicles and mitigate collisions. The influencing factors identified may be improved by safety education. Therefore, simple and effective interventions by health professionals are required that are tailored to pregnant women.

Effects of sedan wheelbase size on left rear-seat occupant injury risk in small offset crashes

The objective of this study was to investigate the effect of sedan wheelbase size on the kinematics and injury severity of left rear-seat occupants by using the finite element (FE) modeling method. A total of 270 cases with detailed accidental information records were analyzed to define the influence laws of wheelbase size and impact speed on the injury of left rear-seat occupants. First, the THUMS (Ver. 4.0.2) FE model was used to reconstruct two small offset collisions with different wheelbases size and unbelted left rear-seat occupants, and the effectiveness of the accident model was verified. Then, seatbelts were added to the left rear-seat occupant models. Finally, LS-DYNA software was used to study the correlation among head and chest injury and five sedan wheelbases sizes (2300, 2450, 2600, 2750, and 2905 mm) at three impact velocities (54, 64, and 74 km/h). The results showed that the occupants’ chest injuries showed an upward trend at the impact velocity of 64 and 74 km/h when the wheelbases sizes was reduced to 2300 mm. This research illustrated that at higher impact velocities, excessively small wheelbases might increase the chest injury severity of left rear-seat occupants.

Characteristics of bodily injuries of the pelvic girdle and lower extremities in car trauma

Background. Fractures of the pelvic girdle and lower extremities as a result of a road traffic accident are the most frequent localization of injuries in victims, however, the structure of pedestrian and intra-salon injuries has not been sufficiently studied. Objective - to study the nature of injuries in victims of a car injury to the pelvic girdle and lower extremities. Methods. Research material - 170 acts of primary forensic medical examinations of victims with fractures of the pelvic bones and long bones of the lower extremities, received as a result of a non-lethal automobile injury. An expert assessment of the nature of bodily injuries was carried out at the Kharkiv Regional Bureau of Forensic Medicine (KRBSFM) within a period of no more than 1 month after injury. Acts of primary forensic medical examinations were selected at random for the period February - June 2018. Research methods - retrospective analysis, descriptive statistics. Results. Among the injured as a result of a car injury - 129 (75.9%) pedestrians, 23 (13.5%) drivers, 14 (8.2%) front seat passengers and 4 (2.4%) rear seat passengers. Thus, pedestrians and car drivers are the most vulnerable to road traffic injuries; the most protected rear seat passengers. Men predominated among the drivers; in the remaining groups of victims, the gender distribution was generally even. Among the participants in the accident were mainly people of working age. Injuries to the chest (26.5%), head (25.9%), abdomen (16.5%) prevailed among the associated injuries. Conclusion. A distinctive feature of injuries sustained as a result of a collision of a pedestrian or a car with another car with a relatively low speed of movement was an isolated injury to the bones of the pelvic girdle or lower extremities, both during pedestrian and intra-salon trauma. All the victims had injuries of the integumentary system of various localization in the form of subcutaneous hematomas and abrasions (158; 92.9%), bruised lacerations (96; 56.5%), stamp injuries (62; 36.5%). The main mechanism of pedestrian injury is the direct impact of the traumatic force with the formation of primary injuries in the form of bumper fractures of the shin bones (35.9%), hip (22.4%) and pelvis (10%).