# Improvement of Boeing Bump Method Considering Aircraft Vibration Superposition Effect
## 3 Simulation of Aircraft Dynamic Response  
### ADAMS/Aircraft Virtual Propotype  
The modeling logic applied in ADAMS/Aircraft is bottom-up, which means that it combines the basic components through several levels to form a complete machine model [15]. The aircraft model structure includes the following components:  
* Part: A part is the smallest unit and is built by referring to the Hardpoint (for spatial positioning) and the Construction Frame (for spatial positioning and orientation). The geometric type (Link or Arm), size, material, mass, and moment of inertia of the component can be set using the dialog box in ADAMS/Aircraft.
* Template: The separate parts are assembled into a template by setting Attachments or Forces. The template defines the topological structure of the aircraft model, which is the underlying structure of the prototype model and cannot be used directly for simulation analysis.
* Subsystem: The subsystem is a higher level of the model that is based on the creation of the template. Users can invoke the template to generate the subsystem in Standard mode and then modify the parameters of the subsystem, such as the coordinates of the Hardpoint, the position and direction of the Construction Frame, and the parameters of the property file. However, the subsystem is not used directly for simulation analysis.
* Communicator: The Communicator is used mainly to exchange information between subsystems and includes an Input Communicator or Output Communicator. For example, the Output Communicator that is responsible for the tire installation position and rolling direction in the landing gear subsystem must correspond to the Input Communicator in the Tire subsystem. During assembly, the software will automatically pair the appropriate Communicators.
* Test Rig: The Test Rig is an equipment that is used to store a simulation controller and test the structure of the model. It includes the whole machine simulation test rig, landing gear dynamic simulation test rig, landing gear structure simulation test rig, and wheel simulation test rig. The Test Rig controls the simulation parameters and calculation process during simulation analysis.
* Assembly: The Assembly is the only component that can be used directly for simulation analysis in ADAMS/Aircraft. The Assembly consists of the Test Rig and one or more subsystems and is divided into the following components. The wheel assembly consists only of a single wheel subsystem. The landing gear structure assembly includes the landing gear suspension subsystem and the structure test rig. The landing gear dynamic assembly includes the landing gear suspension subsystem, wheel subsystem, and dynamic simulation test rig. The assembly of the whole machine includes five basic subsystems, i.e., the fuselage subsystem, the nose landing gear suspension subsystem, the front wheel system, the main landing gear suspension subsystem, and the main wheel system, as well as the whole machine simulation test rig.  
ADAMS/Aircraft supports both Template Builder and Standard modes. After building the aircraft components and generating templates in Template Builder mode, users can call the template in Standard mode to complete the assembly of the whole machine model and carry out simulation analysis. Figures 2 presents the specific modeling and assembly processes in ADAMS/Aircraft in the order of 'template-subsystem-assembly' [10].