Simulation of flexible engine block, crank, and valvetrain effects using DADS

This paper discusses how DADS, Dynamic Analysis and Design System, is being applied to predict deformation of engine components due to structural flexibility. By combining multibody dynamics to account for large nonlinear part displacements and modal coordinates for each part from appropriate finite element analyses, a more sophisticated simulation model has been developed. The benefits of this improved simulation method are accurate prediction of loads acting between all parts in the assembly, as well as accurate prediction of local part deformations superimposed on their gross motion. These results provide insight into the interaction and coupling of multiple parts flexing under high engine loads and accelerations. Advanced flexible body animation methods allow visualization of the motion of the complete flexible system and convenient ways to focus on flexible behavior in specific locations. Position, velocity, and acceleration of all parts as well as individual finite element nodes are reported as are reaction forces in the kinematic constraints and loads in the force elements.