摘要:

The survivability of soldiers in the rear of military vehicles when involved in a crash has been identified as an area of major concern. The Australian Army via Project TRANSAFE has developed and evaluated a range of side facing Seat and Seat Belt Systems (SSBS) for the Perentie 4x4 to improve crash survivability. Options which have been evaluated include; bench seat with lap seat belt, bench seat with lap sash seat belt, individual seat with harness, wooden seat with lap sash seat belt and a plastic seat with lap sash seat belt. Tests were conducted on isolated single seating systems and on multiple seating systems simulating the internal structure of the Perentie 4x4. Wooden and plastic prototype SSBS demonstrated a low probability for life threatening head, neck and chest injuries while the bench seat options and individual seat and harness SSBS have a high probability of serious, if not life threatening, head, neck and chest injuries.

ISSN:1358-8265    

DOI:10.1533/cras.1999.0103

出版商:Woodhead Publishing Ltd    

年代:1999

数据来源: Taylor

摘要:

The simulation of impact and run over of a pedestrian by a bus is presented here to demonstrate the fundamentals of the use of integrated multibody based methodologies as accident reconstruction tools. The equations of motion for the pedestrian and bus models are generated in a systematic way and described using a set of natural coordinates. These equations are solved using the augmented Lagrange formulation which accounts for the existence of redundant kinematic constraint equations, arising from the choice of coordinates used in most of the multibody formulations. These constraint equations have a linear-quadratic nature and are therefore simple to evaluate. The pedestrian physical characteristics are scaled parametrically from a biomechanical database with standard anthropometric data In order to prevent the biomechanical model' to achieve physical unacceptable positions, a circumduction cone of control is defined in each articulation. When a relative position between two segments is detected outside the control cone, a penalty resistance torque, representing reaction moments in that articulation, is applied to both segments. The contact between the pedestrian, bus and ground is modeled using a continuous force model. This model evaluates the nonlinear contact force as function of the pseudo-penetration between the two surfaces in contact, their physical characteristics including the materials of the bodies and relative impact velocity between them. The contact surfaces, for the ground, biomechanical model and bus are modeled using planes and second and higher order ellipsoids respectively. The methodology is finally applied to the impact of a pedestrian by a bus in order to illustrate its use. The initial position of the pedestrian, impact angle and bus forward velocity are defined according to data collected on the field The pedestrian kinematics, the potential for injury and the relative motion between the bus and pedestrian after the impact are evaluated as examples of the results available.

ISSN:1358-8265    

DOI:10.1533/cras.1999.0104

出版商:Woodhead Publishing Ltd    

年代:1999

数据来源: Taylor

摘要:

Classical and non-classical implicit time integration schemes are presented for the transient response of highly nonlinear problems of large deformation analysis exhibiting important material behaviour. These schemes have shown to lead to excellent convergence properties that make them cost efficient alternative to explicit schemes generally advocated as the best choice for these problems. To qualify the theory, examples are presented, whereby performance of the crushed shock-absorber devices, as well as their resolution based on the dynamic buckling of thin steel cylinder phenomenon are given. In these examples, it is shown that implicit schemes are more efficient (less CPU-cost for a given precision of the contact situation and capable of reaching higher precision) than the explicit scheme, despite that both use the Penalty method for the treatment of contact problems.

ISSN:1358-8265    

DOI:10.1533/cras.1999.0105

出版商:Woodhead Publishing Ltd    

年代:1999

数据来源: Taylor

摘要:

The history of public domain finite element models of the side impact anthropometric test dummy are summarized and recent improvements are briefly discussed. The perfomance of the two most recent public domain finite element models are discussed with respect to the predictions of acceleration time histories as compared to standard bench calibration tests as well as an in-vehicle full-scale vehicle crash test. The thoracic trauma indices and the maximum pelvis accelerations are calculated based on the finite element models and are compared to the results obtained in physical calibration tests. The responses and fidelity of the finite element models are discussed and recommendations for further improvements are provided.

ISSN:1358-8265    

DOI:10.1533/cras.1999.0106

出版商:Woodhead Publishing Ltd    

年代:1999

数据来源: Taylor

摘要:

An in-depth analysis of 200 Abbreviated Injury Score (AIS) 2+ injuries to the lower extremity in frontal collisions has been performed using impairment scales devised by the American Orthopaedic Foot and Ankle Society. The most important subgroup of injuries were identified as ankle/hindfoot injuries. There were 63 such injuries sustained by 53 occupants and these were analyzed in greater depth. Inversion or eversion was identified as the mechanism of injury for 40% of injuries. However in 70% of these fractures caused by inversion or eversion, minimal or no long term impairment would be expected. Injuries associated with significant long-term impairment were attributed to axial forces (i.e. loads perpendicular to the foot). Combined vehicle/injury analysis demonstrated a strong association between toe-pan intrusion and these injuries. Interaction between the occupant and the pedals was identified as a probable injury source in only 25% of injuries to the ankle and hindfoot. The results of this study are being used to plan a program of biomechanical research to establish injury risk functions for the ankle and hindfoot.

ISSN:1358-8265    

DOI:10.1533/cras.1999.0107

出版商:Woodhead Publishing Ltd    

年代:1999

数据来源: Taylor

摘要:

Environmental conditions such as temperature and humidity influence both mechanical material properties and crash behaviour of composite structures in service. This paper investigates the effect of temperature on the crash behaviour of tubes made of polyamide 12 reinforced with twill 1/3 glass fibre textile. These composite tubes, manufactured from two hat shaped half-tubes welded together. were impact tested at temperatures between −30°C and 90°C using a 45 kg impactor mass released at an average velocity of 10 m/s. Crash characteristics such as mean force and specific absorbed energy arc shown to decrease significantly with rising temperature. The specific absorbed energy dropped almost linearly with respect to temperature changes. The main observed failure mode of the impacted tubes is lamina bending. Furthermore, material samples were tested under three-point-flexural tests employing similar temperature conditions in order to understand the temperature dependency phenomenon. The results were then checked for correlation between crash characteristics and flexural strength. Both crash tests and flexural tests show similar behaviour in relation to the temperature.

ISSN:1358-8265    

DOI:10.1533/cras.1999.0108

出版商:Woodhead Publishing Ltd    

年代:1999

数据来源: Taylor

ISSN:1358-8265    

DOI:10.1533/cras.1999.0109

出版商:Woodhead Publishing Ltd    

年代:1999

数据来源: Taylor