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SIMON is a new vehicle dynamic simulation model. Applications for SIMON include single- and multi-unit vehicle handling simulation in severe limit maneuvers (including rollovers) and 3-dimensional environments. Applications also include vehicle-to-vehicle and vehicle-to-barrier collisions. This paper provides the technical background for the SIMON engineering model. The 3-dimensional equations of motion used by the model are presented and explained in detail. The calculations for suspension, tire, collision, aerodynamic and inter-vehicle connection forces and moments are also developed. The integration of features available in the HVE Simulation Environment, such as DyMESH, the Driver Model, Brake Designer and Steer Degree of Freedom, is also explained. Finally, assumptions and limitations of the model are presented.

A new three-dimensional collision simulation algorithm, called DyMESH (Dynamic MEchanical SHell) was recently introduced.[1]* This paper presents a validation of DyMESH for vehicle vs. barrier collisions. The derivation of the three-dimensional force vs. crush relationship was described previously.[1] Here the application of three-dimensional force vs. crush curves using the outlined methodology is shown to be effective. Nonlinear force versus crush relationships are introduced for use in DyMESH. Included are numerous DyMESH collision simulations of several types of vehicles (e.g., light and heavy passenger car and sport utility) compared directly with experimental collision test results from various types of barrier tests (e.g., full frontal, angled frontal, and offset frontal). The focus here is not on the vehicle’s change in velocity, but on the acceleration vs. time history.

Two-dimensional collision simulation has been used successfully for two decades. Two- and three-dimensional momentum methods are also well known. Three-dimensional collision simulation can be accomplished using finite element methods, but this is not practical for interactive collision simulation due to long mesh generation times and run times which may take several days. This paper presents an approach to collision simulation using a new algorithm to track interacting vehicle surface meshes. Three-dimensional forces due to vehicle crush are taken into account during the solution and the damage profile is visualized at run time. The new collision algorithm is portable in that it takes as input vehicle material properties and surface geometries and calculates from their interaction three-dimensional forces and moments at the vehicle center of gravity. Intervehicle mesh forces may be calculated from a user-defined force-deflection relationship. The derivation is discussed.