The two most common uses of multibody dynamic software are virtual prototyping and trouble shooting an existing design. The goal of employing a multibody dynamics code is often to reduce the number of physical prototypes that must be actually built. This will in turn limit design costs by reducing the amount of physical testing required. The other common use of multibody dynamics codes is in the analysis of a pre-existing design in a trouble shooting mode. In this trouble shooting context a design is already in production and problems with the design arise that a multibody code can diagnose. Both of these uses of a multibody dynamics code can significantly reduce the cost of an overall design and both point to the significant value of the use of multibody codes. However, for multibody dynamics codes to have an even bigger impact they need to be employed earlier in the design.
One tool that can help integrate multibody dynamics into the design process is sensitivity analysis. Combining sensitivity analysis with multibody dynamics tools allows exploration of the sensitivity of a design with respect to a large number of design variables. In particular, sensitivity analysis gives insight into how to change the parameters of a design that not only affect the motion of the resulting design, but also in the loads and reaction forces of the resulting mechanism.
This paper will describe the mathematical formulation and implementation of design sensitivity techniques into a commercial multibody dynamics code.
