The DFG project focuses on the development of adjustable impedance elements (AIE) for applications in dynamic test rigs. One of the investigated test environments is the DFG-funded multiaxial hexapod at the TUHH. Realistic test environments are to be generated by AIE for aircraft cabin systems and lightweight structures.

Motivation

The dynamic behavior of a system is influenced by the boundary conditions at the system boundary between the test object and the environment. In particular, the dynamic behavior of systems under vibration load depends on the mechanical properties, such as stiffness and damping characteristics, at the system boundaries. In dynamic test engineering, the mechanical properties of the system boundary must be replicated as realistically as possible to enable reliable and accurate test results. Mapping the properties of the system boundaries that are not static for all test scenarios is extremely time-consuming, since individual connecting elements have to be designed for each scenario to map the real mechanical properties.

One approach to address this issue is the development of connecting elements with adjustable stiffness and damping behavior. The aim of the presented AIProVE project is to develop adjustable impedance elements (AIE). Adjustable impedance elements are passive machine elements which consist of an adjustable stiffness element (ASE) and an adjustable damping element (ADE) and thus allow the adjustment of their dynamic properties at the interface. 

Adjustable Impedance Element (AIE) Requirements

Systems and structures in the aerospace sector, as studied at PKT, and products in the power tools sector, as studied at IPEK, are examples where the dynamic behavior is significantly dependent on the mechanical properties of the system boundaries. Lightweight structures in the passenger cabin of an aircraft, such as galleys, lavatories and overhead bins, must sustain dynamic loads. Currently, the difficulty is that attachment elements are designed to be as stiff as possible for the validation of lightweight aerospace structures. In order to investigate realistic dynamic behavior, individual connection elements must be used for each test case, which entails a high testing effort.
 

figure: Schematic of the adjustalble impedance elements between the hexapod and the aircraft galley on the PKT.

Procedure for the development of the AIEs

1.definition of requirements in terms of stiffness, damping, load and frequency.
2.development of adjustable stiffness and damping elements and their mechanical analysis
3.synthesis to adjustable impedance elements
4.Improvement of test conditions in the field of lightweight structures and power tools.

Principal Investigator: Prof. Dr.-Ing. Dieter Krause

Co-Investigator: Emil Heyden, M.Sc.

Funding and Partners

The project AIProVE is funded at the PKT (TUHH), IPEK (KIT) and pd|z (ETHZ) by the deutschen Forschungsgemeinschaft (DFG) and Schweizer Nationalfonds (SNF). The project period is from July 2018 to December 2021.