| 1. |
- Mroz, Krystoffer, 1966, et al.
(författare)
-
Comparison of Hybrid III and human body models in evaluating thoracic response for various seat belt and airbag loading conditions
- 2010
-
Ingår i: IRCOBI Conference. - 9783033025509 ; , s. 265-279
-
Konferensbidrag (refereegranskat)abstract
- Thoracic responses between the Hybrid III model and the THUMS human body model were compared in three frontal impact severities for two belt (3-point and criss-cross), two belt load limiter (constant and degressive) and two airbag types (symmetric and non-symmetric). The thoracic responses were evaluated by measurements of chest deflections (mid-sternum and multi-point measured), chest excursions and, for the human body model, supplemented by maximum rib strains. For the 3-point belt, an overall correlation was found between Hybrid III and THUMS chest deflections and excursions as well as between THUMS multi-point chest deflections and rib strains. For the criss-cross belt, Hybrid III chest deflections increased and THUMS rib strains decreased. For the non-symmetric airbag, Hybrid III and THUMS chest deflections decreased.
|
|
| 2. |
- Andersson, Marianne, 1969, et al.
(författare)
-
Characteristics of crashes involving injured children in side impacts
- 2011
-
Ingår i: International Journal of Crashworthiness. - : Informa UK Limited. - 1358-8265 .- 1754-2111. ; 16:4, s. 365-373
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to define the crash characteristics of near-side impact crashes in which children seated in the rear rows are injured. The crash characteristics included the direction of force, heading angle, horizontal impact location, vertical impact location, extent of deformation and intrusion at the child occupant's seating position. Cases from in-depth crash investigation databases of the NASS-CDS (National Automotive Sampling System-Crashworthiness Data System), CIREN (Crash Injury Research and Engineering Network) and Chalmers University of Technology were reviewed. The principal direction of force was most frequently between 60° and 75°. The heading angle of the bullet vehicle was most commonly between 61° and 90°. The bullet vehicle hit the passenger compartment of the target vehicle, particularly the rear door. Often, one or both of the adjacent pillars to the rear door were involved, most commonly the B pillar. In 11 of 16 crashes, the car sill was not engaged. Most commonly, the deformation extent was into Zone 3 or more – about 40 cm – and the intrusion at the child's seating position was in the range 20–30 cm. This review of the crashes revealed differences between the current side impact test procedures and the actual side impact crashes in which children were injured.
|
|
| 3. |
- Andersson, Marianne, 1969, et al.
(författare)
-
Evaluation of the Head Kinematics of the Q3 Model and a Modified Q3 Model by Means of Crash Reconstruction
- 2012
-
Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 13:6, s. 600-611
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: One objective of this study is to evaluate the head kinematics of the Q3 model. Another objective is to evaluate the effect on head kinematics of increased thoracic spine flexibility; more humanlike mass distribution; and more humanlike body geometry in the Q3 model. The evaluations were based on the head kinematics of children deduced from real crashes and on new data of mass distribution and updated body dimensions for 3-year-olds. Methods: The head kinematics of the Q3 model was evaluated by comparing the Q3 model's head displacement response with the deduced response of 3-year-old children in real crashes. To do so, data from crashes were collected. The data were used to develop the mathematical vehicle and restraint system models (MADYMO, TASS, the Netherlands). Three crashes involving 3-year-old children in frontal impacts were reconstructed. The models were run 35 times each (one model per crash), each time with a different setting to each of the variables for which the exact value was not known. Examples of those variables include crash pulse, initial dummy position, and initial seat belt position. Two versions of the Q3 model were used: one that correlated with the Q3 ATD and one that was modified regarding anthropometry and thoracic flexibility. The basis for the updated anthropometry was new data regarding characteristic dimensions and mass distribution collected at a Swedish hospital. Results: In the anthropometry study, 26 children were measured. The main differences between the average of the measured children and the Q3 model were found in the mass distribution of the torso and thighs: the Q3's pelvis was too heavy and the thorax, abdomen/lumbar spine, and thighs were too light. Another difference was identified in the buttock-knee length. Two of the 3 reconstructed crashes had confirmed head impacts. The Q3 model responded with head kinematics that reflected the deduced courses of events for the real children in one of 3 crashes (the one without head impact). The modified Q3 model reflected the real children in 2 of 3 crashes. Conclusions: In high-severity, straight frontal crashes, the Q3 model predicted non-head impact adequately. However, in oblique frontal crashes, the Q3 model did not sufficiently predict the head impacts. The modified Q3 model predicted the head impacts better than the Q3 model did. Greater flexibility of the thorax and redistributed mass made a positive difference regarding the head kinematics.
|
|
| 4. |
- Andersson, Marianne, 1969, et al.
(författare)
-
Parameter study for child injury mitigation in near side impacts through FE simulations
- 2012
-
Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 13:2, s. 182-192
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: The objective of this study is to investigate the effects by crash related car parameters on head and chest injury measures for 3- and 12-year-old children in near side impacts.Methods: The evaluation was made by using a model of a complete passenger car which was impacted laterally by a barrier. The car model was validated in two crash conditions: the IIHS and the USNCAP side impact tests. The SID-IIs and the HBM3 (THUMS 3-yo) finite element models were used for the parametric investigation (HBM3 on a booster). The car parameters were: vehicle mass, side impact structure stiffness, a head airbag, a thorax-pelvis airbag, and a seat belt with pretensioner. The studied dependent variables were: resultant head linear acceleration, resultant head rotational acceleration, chest viscous criterion, rib deflection, and relative velocity at head impact. The chest measurements were only considered for the SID-IIs.Results: The head airbag had the greatest effect on the head measurements for both of the occupant models. On average, it reduced the peak head linear acceleration by 54 g for the HBM3 and 78 g for the SID-IIs. The seat belt had the second greatest effect on the head measurements; the peak head linear accelerations were reduced on average by 39 g (HBM3) and 44 g (SID-IIs). The high stiffness side structure increased the SID-IIs head acceleration, while it had marginal effect on the HBM3. The vehicle mass had marginal effect on SID-IIs head accelerations, while the lower vehicle mass caused 18 g higher head acceleration for HBM3 and the greatest rotational acceleration. The thorax-pelvis airbag, the vehicle mass and the seat belt pretensioner affected the chest measurements the most. The presence of a thorax-pelvis airbag, high vehicle mass and a seat belt pretensioner all reduced the chest VC and peak rib deflection in the SID-IIs.Conclusions: The head and thorax-pelvis airbags have the potential to reduce injury measurements for both the SID-IIs and the HBM3, provided that the airbag properties are designed to consider these occupant sizes also. The seat belt pretensioner is also effective, provided that the lateral translation of the torso is managed by other features. The importance of lateral movement management is greater the smaller the occupant is. Light vehicles require interior restraint systems of higher performance than heavy vehicles do to achieve the same level of injury measures for a given side structure.
|
|
| 5. |
- Andersson, Marianne, 1969, et al.
(författare)
-
Rear Seat Child Safety in Near-Side Impacts: A Modeling Study of Common Sitting Positions
- 2013
-
Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 14:2, s. 198-208
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: The purpose of this study was to evaluate and propose improvements to the injury mitigation systems, in near-side impacts, for 6 common sitting positions of young adolescents using a previously validated model. Methods: The evaluation was made by using a model of a complete passenger car, including head and thorax–pelvis air bags, which was impacted laterally by a barrier in 2 load cases. The SID-IIs finite element model was used for the evaluations and was seated in 6 different positions in the rear outboard seat: the nominal anthropomorphic test device (ATD) position, 1 inboard position, 3 outboard positions, and 1 braking (forward) position. These positions have previously been identified as common sitting positions in awake and asleep children. The studied dependent variables were head injury criterion (HIC) 36, resultant head linear acceleration, resultant head rotational acceleration, chest viscous criterion, and chest deflection. Results: The lowest head injury measures were seen in the braking positions and in the nominal ATD position, and the highest were seen in the inboard and outboard positions. The lowest chest injury measures were recorded in the inboard and nominal ATD positions, and the highest were recorded in the outboard and braking positions. The occupant in the outboard positions interfered with the air bags during their deployment. The occupant in inboard and braking positions tended to push the curtain air bag over the windowsill. Conclusions: Studies that investigate the injury mitigation effects in common sitting positions, beyond the nominal ATD position, are essential to highlight means to provide improved and robust safety for child occupants. This study was based on the SID-IIs 5th percentile female, which has very similar anthropometry to a 50th percentile 12-year-old. Therefore, the conclusions of this study are applicable to many 11-year-olds up to young adolescents, as well as to small females.The outboard and inboard positions of this study resulted in the highest head injury measures. Although all of the injury measures were only slightly higher than the nominal position, the trends suggest that, in near-side impacts, these positions should be discouraged. The extensively outboard positions resulted in unfavorable air bag positioning during deployment. The inboard position resulted in head strikes further forward of the nominal one; the curtain air bags need inflated cells at all locations of head strike.
|
|
| 6. |
- Brynskog, Erik, 1989, et al.
(författare)
-
Population Variance in Pelvic Response to Lateral Impacts - A Global Sensitivity Analysis
- 2022
-
Ingår i: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - 2235-3151. ; 2022-September, s. 173-196
-
Konferensbidrag (refereegranskat)abstract
- Pelvic fracture remains the third most common moderate to severe injury in motor vehicle crashes, and the dominating lower extremity injury in lateral impacts. An essential tool for analysis of injury, and real-world occupant protection, are finite element human body models. However, today's state-of-the-art pelvis models do not adequately consider the variability in shape and size naturally occurring in human populations. In this study, we developed a new detailed pelvis finite element model, morphable to enable representation of the population shape variance. The model was validated using force-displacement data from post-mortem human subjects, in lateral loading of the denuded pelvis, followed by a global sensitivity analysis. The results suggests that in lateral impacts to the pelvis, pelvic shape contributes to the model response variance by the same magnitude as pelvic bone material stiffness, and that each of these contributions are approximately twice that of the cortical bone thickness. Hence, to model pelvic response for a general population accurately, future studies must consider both pelvic shape and the material properties in the analysis. Increased knowledge about population variability, and inclusion in safety evaluations, can result in more robust systems that reduce the risk of pelvic injuries in real-world accidents.
|
|
| 7. |
- Corrales, M. A., et al.
(författare)
-
Explaining and predicting the increased thorax injury in aged females: age and subject-specific thorax geometry coupled with improved bone constitutive models and age-specific material properties evaluated in side impact conditions
- 2024
-
Ingår i: Frontiers in Public Health. - 2296-2565. ; 12
-
Tidskriftsartikel (refereegranskat)abstract
- Predicting and understanding thorax injury is fundamental for the assessment and development of safety systems to mitigate injury risk to the increasing and vulnerable aged population. While computational human models have contributed to the understanding of injury biomechanics, contemporary human body models have struggled to predict rib fractures and explain the increased incidence of injury in the aged population. The present study enhanced young and aged human body models (HBMs) by integrating a biofidelic cortical bone constitutive model and population-based bone material properties. The HBMs were evaluated using side impact sled tests assessed using chest compression and number of rib fractures. The increase in thoracic kyphosis and the associated change in rib angle with increasing age, led to increased rib torsional moment increasing the rib shear stress. Coupled with and improved cortical bone constitutive model and aged material properties, the higher resulting shear stress led to an increased number of rib fractures in the aged model. The importance of shear stress resulting from torsional load was further investigated using an isolated rib model. In contrast, HBM chest compression, a common thorax injury-associated metric, was insensitive to the aging factors studied. This study proposes an explanation for the increased incidence of thorax injury with increasing age reported in epidemiological data, and provides an enhanced understanding of human rib mechanics that will benefit assessment and design of future safety systems.
|
|
| 8. |
- Corrales, M. A., et al.
(författare)
-
Methodology to geometrically age human body models to average and subject-specific anthropometrics, demonstrated using a small stature female model assessed in a side impact
- 2023
-
Ingår i: Computer Methods in Biomechanics and Biomedical Engineering. - : Informa UK Limited. - 1476-8259 .- 1025-5842. ; 26:10, s. 1208-1219
-
Tidskriftsartikel (refereegranskat)abstract
- The aged population has been associated with an increased risk of injury in car-crash, creating a critical need for improved assessment of safety systems. Finite element human body models (HBMs) have been proposed, but require representative geometry of the aged population and high mesh quality. A new hybrid Morphing-CAD methodology was applied to a 26-year-old (YO) 5th percentile female model to create average 75YO and subject-specific 86YO HBMs. The method achieved accurate morphing targets while retaining high mesh quality. The three HBMs were integrated into a side sled impact test demonstrating similar kinematic response but differing rib fracture patterns.
|
|
| 9. |
- Forman, Jason, et al.
(författare)
-
Variability in Body Shape, Superficial Soft Tissue Geometry, and Seatbelt Fit Relative to the Pelvis in Automotive Postures—Methods for Volunteer Data Collection With Open Magnetic Resonance Imaging
- 2024
-
Ingår i: Journal of Biomechanical Engineering. - 0148-0731 .- 1528-8951. ; 146:3
-
Tidskriftsartikel (refereegranskat)abstract
- Variability in body shape and soft tissue geometry have the potential to affect the body’s interaction with automotive safety systems. In this study, we developed a methodology to capture information on body shape, superficial soft tissue geometry, skeletal geometry, and seatbelt fit relative to the skeleton—in automotive postures—using Open Magnetic Resonance Imaging (MRI). Volunteer posture and belt fit were first measured in a vehicle and then reproduced in a custom MRI-safe seat (with an MR-visible seatbelt) placed in an Open MR scanner. Overlapping scans were performed to create registered three-dimensional reconstructions spanning from the thigh to the clavicles. Data were collected with ten volunteers (5 female, 5 male), each in their self-selected driving posture and in a reclined posture. Examination of the MRIs showed that in the males with substantial anterior abdominal adipose tissue, the abdominal adipose tissue tended to overhang the pelvis, narrowing in the region of the Anterior Superior Iliac Spine (ASIS). For the females, the adipose tissue depth around the lower abdomen and pelvis was more uniform, with a more continuous layer superficial to the ASIS. Across the volunteers, the pelvis rotated rearward by an average of 62% of the change in seatback angle during recline. In some cases, the lap belt drew nearer to the pelvis as the volunteer reclined (as the overhanging folds of adipose tissue stretched). In others, the belt-to-pelvis distance increased as the volunteer reclined. These observations highlight the importance of considering both interdemographic and intrademographic variability when developing tools to assess safety system robustness.
|
|
| 10. |
- Genzel, Jonny, et al.
(författare)
-
An Open-Source Finite Element Model of a Generic Car Seat: Development and Validation for Low-Severity Rear Impact Evaluations
- 2022
-
Ingår i: Conference proceedings International Research Council on the Biomechanics of Injury, IRCOBI. - : IRCOBI. - 2235-3151. ; 2022-September, s. 229-242, s. 229-242
-
Konferensbidrag (refereegranskat)abstract
- A Finite Element model of a generic Laboratory Seat was developed to replicate a physical counterpart used in rear-impact volunteer tests. The Laboratory Seat has a simplified design, developed to facilitate replication in computational models. The seat has a flat rigid base and the seatback consists of four horizontal panels attached to side posts by coil springs. The seat model was validated with results from component tests and sled tests, including the Anthropomorphic Test Device, BioRID II. An initial test series was carried out to generate data for component validation: the first set of tests to characterise the coil spring properties; and the second set comprising Impactor Tests on Head Restraint Foam to assess the head restraint material properties. For system level validation, sled tests were conducted both with the empty Laboratory Seat and with the BioRID II. The BioRID II tests were conducted in conjunction with an earlier volunteer test study. Both the component and the sled tests were reproduced in a virtual environment. Good agreement was achieved between the mechanical tests and the computational simulations. The seat model is freely available to use: https://openvt.eu/fem/open-access-laboratory-seat-model.
|
|
