Janusz Kajzer - Academia.edu (original) (raw)
Papers by Janusz Kajzer
The purpose of this study was to investigate changes in the incidence and consequences of car-ped... more The purpose of this study was to investigate changes in the incidence and consequences of car-pedestrian accidents in urban traffic during a ten year period. The study compared the type and severity of the injuries recorded at the hospitals in Gothenburg (Sweden) during 1983-1986 and 1993-1996. The study focused on accidents where the pedestrian was hit by the front part of a car or taxi. The circumstances of the accidents and the impact speed were deduced from police reports. The shape and dimensions of the impacting structures were determined from standardized drawings of the vehicles. Comparing the two time periods, the number of accidents reduced by 38%. The average Injury Severity Score (ISS) reduced overall, especially in children (50%) and the elderly (39%). The occurrence of serious, severe, critical, and fatal injuries (Abbreviated Injury Scale (AIS) 3+) decreased in all regions of the body, and also the distribution of the injuries changed. Serious or more severe injuries ...
A mathematical breakable leg model was developed and implemented into the pedestrian lower extrem... more A mathematical breakable leg model was developed and implemented into the pedestrian lower extremity model. The leg model consists of two rigid-body elements connected by a "fracturable joint". The moment- deformation characteristics of the "fracturable joint" are described by the user subroutines, which were prepared and added to the MADYMO three-dimensional program system. The input data for the "fracturable joint" model originate from available biological specimen tests. Computer simulations of car-pedestrian impact with this modified pedestrian model were conducted at a speed of 31 km/h in four different configurations, and compared with previously performed human leg specimen tests. Different types of bumper compliance and bumper levels were simulated. The bumper force, the accelerations, the condyle contact forces and the ligament strains were calculated during simulations. The results showed that the modified model gave a higher biofidelity than ...
An experimental method for assessing the tolerance to bending moment in the lateral direction of ... more An experimental method for assessing the tolerance to bending moment in the lateral direction of the extended knee joint has been developed. The load response of the lower extremity was measured by means of force transducers. The bending moment transferred through the entire knee joint was calculated, and the motion of the specimen registered by high speed photography. The bending moment in the lateral direction at the first sign of damage of the entire extended knee joint was determined. Damages were assessed by both measuring the knee joint condition, and dissecting the knee region. Seventeen tests were carried out under dynamic conditions. The first and most common damage type to entire knee joint in this loading configuration was stretching and rupture or avulsion of the medial collateral ligament (MCL). These damages are generated by identical mechanisms, that is to say tensional forces acting on the medial knee structures. The mean peak moment correlated with this damage mecha...
In a study based on 200 motorcycle accidents it was shown that the existing protective clothing h... more In a study based on 200 motorcycle accidents it was shown that the existing protective clothing had no effect on the incidence of fractures to knees, elbows and shoulders. Based on the knowledge from those accidents a new motorcycle suit has been constructed. The main goal was to find a shock-absorbing material to protect knees, elbows and shoulders in case of an accident. Confor foam, a medium density urethane foam was tested and found to possess relevant characteristics. The material was tested under experimental conditions and was found to be sensitive to dampness and temperature with a good shock-absorbing effect at +10 to +30 deg C. Experimental studies on the protective effect of different kinds of leather indicated the importance of continuous tests of leather when manufacturing motorcycle suits. The protective effects of the safety suit have been studied in real-life accidents occurring during a two-year period. A preliminary study showed that the number of fractures decreas...
In this paper the mechanisms of injury and the injury tolerances of the lower extremity in car-pe... more In this paper the mechanisms of injury and the injury tolerances of the lower extremity in car-pedestrian accidents are described and analyzed. Based on the analyses of injury mechanisms, a three-dimensional (3D) mathematical model of lower extremity with human-like knee joint and breakable leg elements was developed. The mechanical properties of the model are based on available biomechanical data. Validation of the new developed model was made with results from previously performed experiments with biological specimens. The computer simulations of these experiments were carried out with the model using the MADYMO 3D program. The bumper impact force, the leg acceleration, the condyle interface forces, the ligament forces, and the ligament relative elongation were calculated and compared with the results from experiments with biological specimens. The calculated values from simulations correspond in general to measured parameters in experiments. The model showed a higher biofidelity ...
JSAE Review
Our previous report concerned an analysis of bicyclists struck laterally by cars, which is the mo... more Our previous report concerned an analysis of bicyclists struck laterally by cars, which is the most fatal type of accident. The current study compares the behavior of bicyclists struck frontally and from the rear by cars. Comparatively few bicyclist fatalities occur in frontal crash accidents. The comparison is based on accident analysis and MADYMO simulations using a humanlike model. Bicyclist impact behavior was made clear on the basis of computer simulations. It was found that the initial impact between a bicyclist's knee and the vehicle front structure is very important in reducing the impact velocity of the bicyclist's head.
The proceedings of the JSME annual meeting
The proceedings of the JSME annual meeting
The proceedings of the JSME annual meeting
The Proceedings of The Computational Mechanics Conference
The Proceedings of The Computational Mechanics Conference
Sae Special Publication Pt 56 Usa, 1996
Abstract: This paper generally reviews the following:(1) traffic accidents in India and Sweden; a... more Abstract: This paper generally reviews the following:(1) traffic accidents in India and Sweden; and (2) vehicle-pedestrian accidents in New Delhi and Gothenburg, with the main emphasis on the bus-pedestrian impact situation. Buses were involved in 193 (32%) out of ...
The purpose of this study was to investigate changes in the incidence and consequences of car-ped... more The purpose of this study was to investigate changes in the incidence and consequences of car-pedestrian accidents in urban traffic during a ten year period. The study compared the type and severity of the injuries recorded at the hospitals in Gothenburg (Sweden) during 1983-1986 and 1993-1996. The study focused on accidents where the pedestrian was hit by the front part of a car or taxi. The circumstances of the accidents and the impact speed were deduced from police reports. The shape and dimensions of the impacting structures were determined from standardized drawings of the vehicles. Comparing the two time periods, the number of accidents reduced by 38%. The average Injury Severity Score (ISS) reduced overall, especially in children (50%) and the elderly (39%). The occurrence of serious, severe, critical, and fatal injuries (Abbreviated Injury Scale (AIS) 3+) decreased in all regions of the body, and also the distribution of the injuries changed. Serious or more severe injuries ...
A mathematical breakable leg model was developed and implemented into the pedestrian lower extrem... more A mathematical breakable leg model was developed and implemented into the pedestrian lower extremity model. The leg model consists of two rigid-body elements connected by a "fracturable joint". The moment- deformation characteristics of the "fracturable joint" are described by the user subroutines, which were prepared and added to the MADYMO three-dimensional program system. The input data for the "fracturable joint" model originate from available biological specimen tests. Computer simulations of car-pedestrian impact with this modified pedestrian model were conducted at a speed of 31 km/h in four different configurations, and compared with previously performed human leg specimen tests. Different types of bumper compliance and bumper levels were simulated. The bumper force, the accelerations, the condyle contact forces and the ligament strains were calculated during simulations. The results showed that the modified model gave a higher biofidelity than ...
An experimental method for assessing the tolerance to bending moment in the lateral direction of ... more An experimental method for assessing the tolerance to bending moment in the lateral direction of the extended knee joint has been developed. The load response of the lower extremity was measured by means of force transducers. The bending moment transferred through the entire knee joint was calculated, and the motion of the specimen registered by high speed photography. The bending moment in the lateral direction at the first sign of damage of the entire extended knee joint was determined. Damages were assessed by both measuring the knee joint condition, and dissecting the knee region. Seventeen tests were carried out under dynamic conditions. The first and most common damage type to entire knee joint in this loading configuration was stretching and rupture or avulsion of the medial collateral ligament (MCL). These damages are generated by identical mechanisms, that is to say tensional forces acting on the medial knee structures. The mean peak moment correlated with this damage mecha...
In a study based on 200 motorcycle accidents it was shown that the existing protective clothing h... more In a study based on 200 motorcycle accidents it was shown that the existing protective clothing had no effect on the incidence of fractures to knees, elbows and shoulders. Based on the knowledge from those accidents a new motorcycle suit has been constructed. The main goal was to find a shock-absorbing material to protect knees, elbows and shoulders in case of an accident. Confor foam, a medium density urethane foam was tested and found to possess relevant characteristics. The material was tested under experimental conditions and was found to be sensitive to dampness and temperature with a good shock-absorbing effect at +10 to +30 deg C. Experimental studies on the protective effect of different kinds of leather indicated the importance of continuous tests of leather when manufacturing motorcycle suits. The protective effects of the safety suit have been studied in real-life accidents occurring during a two-year period. A preliminary study showed that the number of fractures decreas...
In this paper the mechanisms of injury and the injury tolerances of the lower extremity in car-pe... more In this paper the mechanisms of injury and the injury tolerances of the lower extremity in car-pedestrian accidents are described and analyzed. Based on the analyses of injury mechanisms, a three-dimensional (3D) mathematical model of lower extremity with human-like knee joint and breakable leg elements was developed. The mechanical properties of the model are based on available biomechanical data. Validation of the new developed model was made with results from previously performed experiments with biological specimens. The computer simulations of these experiments were carried out with the model using the MADYMO 3D program. The bumper impact force, the leg acceleration, the condyle interface forces, the ligament forces, and the ligament relative elongation were calculated and compared with the results from experiments with biological specimens. The calculated values from simulations correspond in general to measured parameters in experiments. The model showed a higher biofidelity ...
JSAE Review
Our previous report concerned an analysis of bicyclists struck laterally by cars, which is the mo... more Our previous report concerned an analysis of bicyclists struck laterally by cars, which is the most fatal type of accident. The current study compares the behavior of bicyclists struck frontally and from the rear by cars. Comparatively few bicyclist fatalities occur in frontal crash accidents. The comparison is based on accident analysis and MADYMO simulations using a humanlike model. Bicyclist impact behavior was made clear on the basis of computer simulations. It was found that the initial impact between a bicyclist's knee and the vehicle front structure is very important in reducing the impact velocity of the bicyclist's head.
The proceedings of the JSME annual meeting
The proceedings of the JSME annual meeting
The proceedings of the JSME annual meeting
The Proceedings of The Computational Mechanics Conference
The Proceedings of The Computational Mechanics Conference
Sae Special Publication Pt 56 Usa, 1996
Abstract: This paper generally reviews the following:(1) traffic accidents in India and Sweden; a... more Abstract: This paper generally reviews the following:(1) traffic accidents in India and Sweden; and (2) vehicle-pedestrian accidents in New Delhi and Gothenburg, with the main emphasis on the bus-pedestrian impact situation. Buses were involved in 193 (32%) out of ...