Fig 18 - uploaded by Christophe Bastien
Content may be subject to copyright.
Source publication
With dramatically rapid development of computing and modelling technology, occupant and pedestrian
safety models went through the development of crash test dummies and multi-body mathematical
dynamic modelling to finite element pedestrian human model (THUMS 4.0). THUMS 4.0 is a state of
art human model which includes a skeleton structure, as well a...
Similar publications
Human modelling is a rather new development in occupant and pedestrian safety simulations in the automotive industry and gained much importance and interest in recent years. However it is still in a very early development phase and the model development and validation is still under heavy development. The general intention of these models is to inc...
Purpose:
The purpose of the current study was to develop and validate a finite element (FE) pedestrian model with high computational efficiency and stability using a novel modeling approach.
Methods:
Firstly, a novel modeling approach of using hollow structures (HS) to simulate the mechanical properties of soft tissues under impact loading was p...
aDrive is a first Polish national project that aims to develop integrated simulation environment comprising realistic traffic scenarios, vehicle driving automation ADA systems models, HMI /human‐machine interfaces/ communications and control links, and HIL /Human in the loop/ simulator testing capabilities for the evaluation of the PRE‐CRASH phase....
![Threshold of stress for lower extremities [21].](publication/381568610/figure/tbl2/AS:11431281253508279@1718895682908/Threshold-of-stress-for-lower-extremities-21_Q320.jpg)
Pedestrians often suffer severe injuries in road traffic accidents. Therefore, pedestrian safety and, more precisely, analysis of injuries of the knee joint and lower limb bones were the focus of this research. A Vietnamese-sized human body model (HBM), named V-THUMS, scaled from the Total Human Model for Safety (THUMS) representing a walking pedes...
The present paper is the first of two companion papers on the investigations of wave overtopping flow striking a cylinder, which is the schematisation of a human body, on the crest of an impermeable sloped seawall with a deep foreshore. This paper presents the physical modelling part. The key measured physical quantities include the overtopping flo...
Citations
... THUMS has been extensively validated against cadaveric studies [6], showing excellent agreement with experimental injuries. Moreover, THUMS simulations have been compared with real-life accident data to show a good correlation in most body regions [7]; however, there are some reported discrepancies in lower limb injuries [8; 9]. This study aims to comprehensively review the THUMS lower limb model focusing on pedestrian impact applications and identify areas for future development. ...
The Total Human Model for Safety (THUMS) is widely used for biomechanics research and validated at the component and full-body levels. Nonetheless, some authors have reported differences in predictions between the model and real-life injuries, particularly in the lower limbs. This study aims to perform an extensive critique of the THUMS lower limb and identify areas for improvement. The THUMS model was assessed across quasi-static and dynamic validation tests to understand geometry, material properties and response to impact. The study has highlighted that the THUMS' geometry is comparable to published cadaveric data for bones and ligaments, but soft tissues (muscle, adipose and skin) and fascia have significant simplifications. The bones' material properties are evidence-based and vary appropriately according to anatomical site. Bone failure is permitted through element deletion; however, the unusually transverse fracture pattern predicted in THUMS is seldom seen in clinical practice. The simplified soft tissue model cannot fail, making it unable to replicate the extensive damage seen in high energy open fractures. Ligament injury is a frequent result of an impact to the pedestrian lower limb, often at the bone-tendon interface, yet the failure location seen in the THUMS model is mid-substance. In summary, THUMS makes an excellent attempt to model the lower limb; nonetheless, some work is still required to increase biofidelity. Improvements in soft tissue geometry and material properties and fracture pattern modelling represent apparent areas for development. 1 Background Injuries to pedestrians remain a significant source of morbidity and mortality. There are over 20,000 pedestrian casualties per year in the UK, with one-third of these resulting in death or severe injury [1]. Lower limb injuries are sustained in up to 30% of road traffic accidents involving pedestrians [2], and they are a source of significant disability and impairment [3]. There has, therefore, been much interest in modelling lower limb injuries. Contemporary advances in computational engineering have led to sophisticated human body models that accurately predict the site and nature of injuries following impact. Numerous models are currently available, exhibiting variation in posture, anthropometry, and age. At the turn of the twenty-first century, the Total Human Model for Safety (THUMS) was pioneered by Iwamoto et al. [4]. The model was based on the anthropometry of a 50 th percentile adult, using cross-sectional imaging to create a detailed mesh complete with skeleton, internal organs and soft tissue coverings. Further refinement has produced age and gender-specific models [4] and the capability to model active muscles [5]. THUMS has been extensively validated against cadaveric studies [6], showing excellent agreement with experimental injuries. Moreover, THUMS simulations have been compared with real-life accident data to show a good correlation in most body regions [7]; however, there are some reported discrepancies in lower limb injuries [8; 9]. This study aims to comprehensively review the THUMS lower limb model focusing on pedestrian impact applications and identify areas for future development. 2 Methodology The critique was conducted by a mechanical engineer with extensive experience in automotive engineering and crash safety as well as a Trauma and Orthopaedic and Plastic and Reconstructive Surgeon, both with experience in managing lower limb trauma. THUMS AM50 version 4.02 was used as the model for evaluation, and an assessment was performed using the Oasys LS-DYNA software suite [10]. The analysis began by assessing the geometry of the model in relation to published anthropometric and cadaveric measurements. Material properties were then assessed in detail alongside a review of contemporary attempts to model biological tissues in regional and full human body models. THUMS kinematic response to impact was reviewed using the validation tests available from Toyota [11]. Specific injury patterns were then analysed, considering physical outputs from each
... The accident reconstruction focused on re-creating the vehicle and the accident circumstances. In order to capture the pedestrian kinematics, the THUMS human model was scaled to match the height and weight of the deceased, and placed in the most likely gait [15] [16], based on of accident report, to replicate an accurate head landing position on the windscreen. ...
Traumatic injuries are measured using the Abbreviated Injury Scale (AIS), which is a risk to life scale. New human computer models use stresses and strains to evaluate whether serious or fatal injuries are reached, unfortunately these tensors bear no direct relation to AIS. This paper proposes to overcome this deficiency and suggests a unique Organ Trauma Model (OTM) able to calculate the risk to life based on the severity on any organ injury, focussing on real-life pedestrian accidents. The OTM uses a power method, named Peak Virtual Power (PVP), and calculates the risk to life of brain white and grey matters as a function of impact direction and impact speed. The OTM firstly calibrates PVP against the medical critical AIS threshold observed in each part of the head as a function of speed. This base PVP critical trauma function is then scaled and banded across all AIS levels using the confirmed property that AIS and the probability of death is statistically and numerically a cubic one. The OTM model has been tested against four real-life pedestrian accidents and proven to be able to predict pedestrian head trauma severity. In some cases, the method did however under-estimate the head trauma by 1 AIS level, because of post-impact haemorrhage which cannot be captured with the employed Lagrangian Finite Element (FE) solver. It is also shown that the location of the injury predictions using PVP coincide with the post mortem reports and are different to the predictions made using maximum principal strain.
... Utilisation of more detailed human model e.g. THUMS can be of high benefit as it enables for localisation of the single organ trauma [20]. Moreover, it enables for better representation of the human body kinematics. ...
High speed vessels can be injurious when crashing. This paper reviews potential passengers injuries and proposes a bracing position to mitigate head, neck and chest injuries.
Pedestrian accident reconstruction is necessary to establish cause of death, i.e. establishing vehicle collision speed as well as circumstances leading to the pedestrian being impacted and determining culpability of those involved for subsequent court enquiry. Understanding the complexity of the pedestrian attitude during an accident investigation is necessary to ascertain the causes leading to the tragedy. A generic new method, named Pedestrian Crossing Speed Calculator (PCSC), based on vector algebra, is proposed to compute the pedestrian crossing speed at the moment of impact. PCSC uses vehicle damage and pedestrian anthropometric dimensions to establish a combination of head projection angles against the windscreen; this angle is then compared against the combined velocities angle created from the vehicle and the pedestrian crossing speed at the time of impact. This method has been verified using one accident fatality case in which the exact vehicle and pedestrian crossing speeds were known from Police forensic video analysis. PCSC was then applied on two other accident scenarios and correctly corroborated with the witness statements regarding the pedestrians crossing behaviours. The implications of PCSC could be significant once fully validated against further future accident data, as this method is reversible, allowing the computation of vehicle impact velocity from pedestrian crossing speed as well as verifying witness accounts.
