Option 1: 3pc BeamFor this option, a trailing arm is assumed to be a 3 piece beam element. The user has to enter 4 geometry point to describe the beam element. The four geometry point is described in the figure below.
Option 2: Rev Joint with Rotational StiffnessIf the user selects this option, Adams/Chassis will create a rev. joint and a spring rotational stiffness between a trailing arm and a spindle. The following figure shows how a trailing arm is connected to a spindle and a body when this option is selected.
To construct a trailing arm part, Adams/Chassis looks for "trailing_arm_body", "trailing_arm_spindle" and "trailing_arm_spindle_ori" in a geometry table. It is also required to enter a "trailing arm rot. spring rate (N/mm/rad)".
In this option, one side of a trailing arm is connected to an upper and a lower spindle and the other side of a trailing arm is connected to a body as shown below. Adams/Chassis will look for"trailing_arm_body","trailing_arm_spindle" and "trailing_arm_to_spindle".
In this option, one side of a trailing arm is connected to an upper and lower control arms and the other side of a trailing arm is connected to a body as shown below. Adams/Chassis looks for "trailing_arm_body","trailing_arm_spindle" and "trailing_arm_to_spindle".
To use this option, it is also required to enter a trailing arm rotational spring rate, cross sectional configuration, tube thickness, height and base. 
You can enter the user defined c.g. location in a PART table. If you choose to use "default c.g." option, the trailing arm c.g. point is assigned as the "trailing_arm_body". 
