This chapter discusses and demonstrates how to use the “Static” module In SolidWorks Simulation to run an FEA simulation on assemblies. The procedure and skills discussed in Chap. 3 can be directly implemented in this chapter except that there are interfaces on an assembly. First, three types of contact interactions on an interface of assembly in SolidWorks Simulation are discussed and explained. They are “Bonded”, “Contact” and “Free”. They can be defined by three different approaches which are “Global interaction (default)”, “Local interaction” and “Component interaction”. Several examples with step-by-step instructions are provided to demonstrate how to define the type of contacts and run FEA simulation on an assembly. Second, if some components in an assembly are designed by other specific approaches such as pins and bolts, they can be simplified as mathematical models (connectors) in the assembly. Several typical connectors such as pin, bolt, and interference fit are presented and demonstrated. Third, examples of truss elements and beam elements will be discussed in this chapter because they are typically assemblies. Fourth, there is a mixture of different elements in an FEA simulation on an assembly because different components can be meshed by different types of elements. One example is presented to demonstrate a mixture of solid, beam, and shell elements in FEA simulation on an assembly. Finally, a major design project in FEA simulation on a real product will be presented.