Janusz Kajzer

Kabimec Consulting

The objectives of this research are to propose a new impact response corridor for the ISO legform impactor and to determine the biofidelity of the current legform impactor with rigid leg and thigh developed by the Transport Research Laboratory (TRL). The latest data obtained from Post Mortem Human Subject (PMHS) knee impact tests were analyzed in c...

In vehicle-pedestrian collisions, lower extremities of pedestrians are frequently injured by vehicle front structures. In this study, a finite element (FE) model of THUMS (total human model for safety) was modified in order to assess injuries to a pedestrian lower extremity. Dynamic impact responses of the knee joint of the FE model were validated...

Bicyclist and pedestrian injuries in collisions with vehicles in Japan were investigated based on national and in-depth accident data analyses and mathematical simulations. In an impact with a bonnet-type vehicle, a bicyclist slides over the bonnet of the vehicle, behavior that is not observed for pedestrians. As a result, the bicyclist's head tend...

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...

In the present study, a previously developed finite-element model of the neck was modified by adding the Hill-type muscle elements. The modified model was utilized to investigate the muscle effects on the kinematic responses of the head-neck complex in a frontal impact at a speed of around 60 km/h. The behavior of this model was consistent with the...

Myoelectric signals [electromyograms (EMGs)] can be collected using either surface or fine-wire electrodes. Application of the latter results in higher-frequency contents of EMG. In the field of impact biomechanics, surface electrodes are more often utilized than fine-wire ones. However, the removal of motion artefacts from EMG recorded under trans...

The kinematics and injury risks of occupants who are not standard size, such as small female driver and children were examined by using MADYMO. The child in the child restraint system with passenger airbag, and female on the driver seat were analyzed. The three-year-old child dummy, AM50th% dummy and AF5th% dummy were used in this study. The result...

The number of pedestrian fatalities accounts for about 1/3 of all traffic accident fatalities in Japan. Therefore, Many car to adult pedestrian accident analyses were carried out to propose countermeasure for protection of pedestrian. But, so far, the study of car to child pedestrian accident has not been conducted so much. So, In this paper, car t...

In this paper, in order to investigate strain distribution of MCL, maximum strain at insertion part and midsubstance of ligament was examined. There was no significant difference between the maximum strain at tibial insertion and the maximum strain at femoral insertion at 0.01mm/s, 0.3mm/s, 10mm/s. Although there were no significant differences, th...

In Japan, bicyclists account for approximately 10% of all the victims killed in traffic accidents annually. This indicates that, in addition to accidents involving pedestrians, attention should be paid to these involving bicyclists. This study compares the behavior of bicyclists and pedestrians struck laterally by cars. Comparison is made based on...

In vehicle-pedestrian impacts, the kinematics and severity of pedestrian injuries are affected by vehicle front shapes. Accident analyses and multibody simulations showed that for mini vans the injury risk to the head is higher, while that to the legs is lower than for bonnet-type cars. In mini-van pedestrian impacts, pedestrians ran high risks of...

Truck and bus frontal impacts account for a major proportion of pedestrian fatalities in many less motorized countries. To understand this phenomenon, we have collected injury data on pedestrian impacts with buses and trucks and performed computer simulations to identify critical design parameters at 15–45 km/h impact velocities for further investi...

A string of series-connected Hill-type bars is proposed for modeling the effect of muscle tension on human body kinematics in a car collision. The preliminary results indicated that such strings exhibit oscillations and instabilities when subjected to a large and transient stretch. A new algorithm for calculation of the force-velocity of the deform...

Although the effects of strain rate on the mechanical properties of ligaments and tendons has been one of the most popular subjects of investigation, many issues remain to be clarified. Moreover the strain rate conditions in most studies were not fast enough for the examination of injury prevention in traffic accidents. As for skeletal muscle, only...

In the current study, the finite element model of the cervical spine with muscles, previously applied to an investigation of the head-neck complex responses in frontal impacts, was modified in order to improve its biofidelity in low-speed rear-end impacts. The modified model of the cervical spine was utillized to investigate effects of muscle tensi...

Human biomechanics is an important research field in achieving safety, health, comfort, and a high quality of life in a world where the older generation soon will outnumber the younger generation. Recently there have been significant developments in this new field ofresearch, addressing such issues as injury prevention in various types of accidents...

A mathematical model is formulated for activated muscles under stretching. "Yielding", which is characterized as the decrease in the rate of muscle force during stretching, is reported in the literature for activated cat soleus muscles. We hypothesize that such "yielding" mainly results from the change of an active state that is determined by step...

Compatibility problems in car-to-car frontal, side, single car and car-to-pedestrian collisions in Japan are discussed using traffic accident data. The number of serious and fatal injuries is investigated for the subject car and other cars, which are categorized by their class and mass. The aggressivity of the cars is calculated by the number of fa...

The compatibility problem for car-to-car frontal collision is discussed using traffic accident data and simulations of multibody dynamics. The accident analysis shows that the car with masses of 1150 kg is the most compatible in the current car population. The sports utility vehicle and mini car are found to be the most incompatible car types with...

A 2-dimensional multibody model of the head-neck complex with muscle elements was developed to estimate the influence of muscles on the kinematics of the head-neck complex in a frontal car collision. With this model the authors evaluated how strongly the calculated influence of muscles depends on 3 important factors: (a) impact severity, (b) reflex...

The safety of a driver in a mini car was analyzed using MADYMO in crashes into a rigid wall or a large car. The injury risk to the driver in the mini car is examined by investigating the stiffness and restraint system of the mini car. When the stiffness of the mini car is low, the injury risk to its driver is low in a crash into a rigid wall. Howev...

Twelve volunteers participated in the experiment under the supervision of Tsukuba University Ethics Committee. The subjects sat on a seat mounted on a sled that simulated actual car impact acceleration under different impact speeds, seat stiffness, neck muscle tension, and alignment of the cervical spine for the parameter study of the head-neck-tor...

The dynamic responses of the lower extremity to a lateral bumper impact were investigated using a finite element model of the human lower extremity skeleton. The model was implemented using the program LS-DYNA3D and consisted of the femur, the tibia, and the knee ligaments. The stress distribution in the lower extremity was analyzed during the late...

The shearing and bending responses of the knee joint to a lateral impact loading were studied using a 3D multibody system model of the lower extremity. In simulating the lateral shearing response, an impact shearing force was applied to the knee element and the shearing displacement between articular surfaces was calculated. In simulating the later...

Three-wheeled scooter taxis (TSTs) are being used in many Asian countries and along with buses are the main mode of public transport for the urban middle class population. The TST chassis is made by the manufacturer and the body is fabricated by local body-makers. The vehicle is not subject to any crash safety specifications. This work is the first...

The purpose of the present study is to perform mathematical modelling analysis of muscle effect on the kinematics of the human body in a car collision. The study is divided in two parts: 1) Multibody analysis of muscle effect on response of the human head-neck complex in a frontal car collision and 2) Development of finite element Hill-type muscle...

In present study, the computer simulation of dynamic response of the knee joint was carried out with a human lower extremity model to analyze the injury mechanism of this body region, and to predict the risk of injury to the knee joint in extended position from lateral impact shearing and bending loads. A 3D mathematical model of the lower extremit...

Sled impact tests on mechanical substitutes for a pedestrian were conducted as a preliminary study for the purpose of developing a subsystem test procedure for the assessment of car-front aggressiveness to pedestrian legs. Four mechanical substitutes for a pedestrian were used in the test: the leg of a rotationally symmetrical pedestrian dummy (RSP...

A 3D pedestrian knee joint model was developed as a first step towards a new description of the whole pedestrian body for computer simulations. Computer simulations were performed using the MADYMO 3D program to study the influence of the upper body mass on the distribution of the forces in the simulated knee structures. Body mass had an influence o...

The compatibility problems of the mini car in car-to-car frontal collision and car-pedestrian accident are discussed using accident data and computer simulations. In our analysis of the accident data in Japan, the number of fatalities was investigated using the vehicle masses and classes. It was found that the cars with identical mass are most comp...

Paper for presentation at the 10th International Conference on Experimental Safety Vehicles, 1985 Session on Safety Design of 2 Wheeled Vehicles