Behavior Of Cyclist Under Collision Based On Large-scale Simulation

How to mitigate the injuries of human bodies in traffic accidents by improvingthe car structure is still an important question. Compared with pedestrian protection,which has been regulated by laws and regulations, cyclist protection has not drawnmuch attention. Studies by now are mostly based on analysis of limited cases, whilelarge-scale simulations are scarcely reported. This study set up a large database ofvirtual accidents, and analyzed the key factors influencing the cyclists’ head injury,aiming at providing reference for car design regarding cyclist protection.MADYMO was used to build the multibody model which simulated the collisioninvolving vehicle, cyclist and bicycle. An accident from literature was reconstructedas a verification of the model. A simulation platform was set up withmodeFRONTIER, which can manipulate input variables automatically, callMADYMO’s solver, and retrieve outputs finally. A database containing about13000cases were generated.Statistical analysis on the database was conducted for the purpose of studying thecyclist’s head injury. Parametric study and main effect analysis were carried out, anddescriptive statistics were given to reveal the influence of input variables on HIC. Allcases were divided into “ground-dominant” and “vehicle-dominant”, or “miss” and“contact”, and properties of each category were studied. It was shown that carvelocity and the type of cars are the most crucial factors influencing HIC, and theinfluence of other factors is relatively trivial.Kinematics of the cyclist’s head in typical cases was analyzed in detail. In thereference frame of vehicle, overall trajectory and velocity of the head wereinvestigated, and the motion of head was decomposed for a clearer physical picture.The influence of the bicycle offset before impact was studied; a simplified model forhead impact time was built; the head impact angle was investigated quantitatively.A new approach to solving the collision process was introduced. It applies to thesituation where contact stiffness is weakly nonlinear, and approximate analyticalsolution could be obtained. The theoretical framework was established, and a simpleexample was discussed.